Novel Insights from Clinical Practice
HOR MON E RE SE ARCH I N PÆDIATRIC S
Horm Res Paediatr 2015;83:67–72 DOI: 10.1159/000367711
Received: April 7, 2014 Accepted: August 18, 2014 Published online: January 6, 2015
Successful Intermittent Intravenous Calcium Treatment via the Peripheral Route in a Patient with Hereditary Vitamin D-Resistant Rickets and Alopecia Betul Ersoy a Seniha Kiremitci a Tsuyoshi Isojima b Sachiko Kitanaka b a b
Division of Pediatric Endocrinology and Metabolism, Celal Bayar University, School of Medicine, Manisa, Turkey; Department of Pediatrics, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
Established Facts • Hereditary vitamin D-resistant rickets (HVDRR) is a disorder with different biochemical and clinical features caused by different defects within vitamin D receptor gene. • Effective treatment of HVDRR is still controversial.
Novel Insights
Key Words Hereditary vitamin D-resistant rickets · Vitamin D receptor · Intermittent peripheral i.v. calcium therapy
Abstract Background: Hereditary vitamin D-resistant rickets (HVDRR) is a rare genetic disorder caused by mutations in the vitamin D receptor (VDR) gene, which result in end-organ resistance to 1,25-(OH)2D3. Patients with HVDRR are mostly treated using i.v. calcium therapy with a central catheter. However, central catheter-related complications have been reported. Patient: The patient was a 3-year-old boy presenting with
© 2015 S. Karger AG, Basel 1663–2818/15/0831–0067$39.50/0 E-Mail [email protected] www.karger.com/hrp
waddling gait and alopecia. He had hypocalcemia [8 mg/dl (2 mmol/l)], hyperparathyroidism (1,232 ng/l), and elevated 1,25-(OH)2D3 levels (>250 pmol/l). DNA sequence analyses of the VDR gene showed a homozygous C–T transition at codon 152, resulting in a non-sense mutation in exon 5. Interventions and Outcomes: The patient was initially treated with calcitriol (80 ng/kg/day) and high-dose oral calcium (150 mg/kg/day) for one year. At the end of the first year, intermittent (5 days per month) i.v. calcium therapy without a central catheter was initiated because of insufficient clinical and radiological improvement. After 2 years of intermittent i.v. calcium therapy, there was a clear improvement based on clinical progress and on X-ray and biochemical findings. No
Seniha Kiremitci, MD Celal Bayar University, School of Medicine Uncubozköy Mahallesi, Mimar Sinan Bulvarı TR–45030 Manisa (Turkey) E-Mail senihakiremitci @ yahoo.com
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• We report the phenotypic features of a patient with HVDRR linked with homozygous C–T transition at codon 152, in exon 5 of the vitamin D receptor gene, which was previously described. • The patient was treated successfully with i.v. calcium via a peripheral line using a novel method (5 consecutive days a month) without any complications or adverse effects.
Introduction
The rare recessive genetic disease hereditary vitamin D-resistant rickets (HVDRR) is caused by mutations in the vitamin D receptor (VDR) gene which results in endorgan resistance to the 1,25-(OH)2D3 action. The major defect caused by the mutant VDR gene is a decrease in intestinal calcium and phosphate absorption, which leads to decreased bone mineralization, and rickets [1]. Some patients also have total body alopecia [1, 2]. Alopecia has been thought to be associated with increased severity of the disease, although there have also been severe cases without alopecia [3, 4]. Several different types of mutations, such as non-sense mutations, insertions/substitutions, insertions/duplications, deletions, and splice site mutations have been identified in the VDR gene as the cause of HVDRR [5]. Most of these mutations occur at the DNA-binding domain (DBD) of the VDR, but few are located at the ligand-binding domain (LBD) [6]. Many patients with mutations in the DBD have alopecia [5]. Treatment for patients with HVDRR is not standardized. Studies have shown successful treatment results with i.v. [7] and/or oral calcium therapy [8, 9]. However, i.v. calcium therapy requires a central catheter and prolonged hospitalization [10]. One report has described successful therapy with enteral calcium using a nasogastric tube [11]. To our knowledge, there are no studies to date in which peripheral administration of i.v. calcium has been used. In this report, we describe a patient with a homozygous non-sense mutation in the LBD of the VDR gene, which resulted in the syndrome of HVDRR with alopecia. We also demonstrate the success of intermittent i.v. calcium therapy without the need for prolonged hospitalization. Case Description A 3.4-year-old male patient presenting with gait disorder, was admitted to our Pediatric Endocrinology and Metabolism outpatient clinic. He was born full term via normal spontaneous vaginal delivery, with a birth weight of 3.3 kg, and no complications. Birth
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Horm Res Paediatr 2015;83:67–72 DOI: 10.1159/000367711
length and head circumference are not known. Alopecia was noted at birth. His mother’s pregnancy was uncomplicated. He is the first child of a nonconsanguineous Turkish family from the western part of Turkey. He received prophylactic vitamin D supplements from the age of 14 days to one year. At presentation, his height was 90 cm, height standard deviation score (SDS) was –2.08 and the weight was 12.5 kg (SDS: –1.9) according to national growth data [12]. Examination showed no scalp hair, scanty eyebrows and eyelashes, metaphyseal widening of his wrist and ankles, and bowing of his upper and lower extremities. He had a waddling gait and could not maintain his balance while walking. The initial biochemistry revealed a serum total calcium level of 8.0 mg/dl (normal range: 8.1–10.4 mg/dl), inorganic phosphorus 3.8 mg/dl (normal range: 2.5–4.5 mg/dl), alkaline phosphatase (ALP) 661 U/l (normal range: 145–420 U/l), and parathyroid hormone (PTH) 1,232 ng/l (normal range: 15–65 ng/l). His 25(OH)D level was 21 ng/ml (normal range: 9–37 ng/ml), and the 1,25(OH)2D3 was greatly elevated at >250 pmol/l (normal range: 39–102 pmol/l). The urine calcium to creatinine ratio was low at 0.02 (normal range: 0.05–0.2). Wrist X-ray revealed cupping and fraying of the metaphysis, and widening of the epiphysis. A skeletal survey showed a cystic lesion and a fracture in the upper part of the humerus due to hyperparathyroidism. While the initial biochemistry was suggestive of nutritional rickets, the elevated 1,25(OH)2D3 levels and the severity of rickets both clinically and radiologically raised the suspicion of a possible HVDRR. After obtaining informed consent from the parents, this diagnosis was subsequently confirmed by DNA sequencing. Genetic Analysis The study was performed with the approval from the Ethics Committee of The University of Tokyo and Celal Bayar University Faculty of Medicine. Genomic DNA was isolated from the peripheral blood at the genetic laboratories of Celal Bayar University Faculty of Medicine. The entire coding region and exonintron boundaries of the VDR gene were amplified from genomic DNA by polymerase chain reaction (PCR), using designed PCR primers. Information on the PCR primers and the PCR conditions will be provided on request. Subsequently, PCR products were sequenced using an ABI Prism BigDye Terminator Cycle Sequencing Ready Reaction Kit (PE Applied Biosystems, Foster City, Calif., USA), and the forward and reverse primers from the PCR amplification. Direct sequencing in both directions was performed on an autosequencer (PE for consistency Applied Biosystems 3130x1, Genetic Analyzer). Q152X, the VDR gene at exon 5 homozygous mutation was identified. The patient was found to have a homozygous C–T 140 transition at codon 152, resulting in a non-sense mutation, Q152X, in exon 5 of the VDR gene. Both parents were found to be heterozygous for this mutation (fig. 1). Clinical and biochemical analyses of the parents were normal. Treatment The patient was initially treated with calcitriol (80 ng/kg/day) and high-dose oral calcium (150 mg/kg/day) for one year. During the first year of treatment, the patient showed no improvement in the clinical, laboratory and radiological findings. His height velocity was 4 cm per year, and his height SDS fell to –2.46. Laboratory findings showed that the ALP (585 U/l) and PTH 148
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peripheral complications were reported either. Conclusion: HVDRR with a non-sense mutation in the ligand-binding domain and alopecia was successfully treated with intermittent i.v. calcium without a central catheter. © 2015 S. Karger AG, Basel
Fig. 1. DNA sequence of the patient, his father and mother in the VDR gene. The patient has a homozygous C–T transition at codon 152, resulting in a non-sense mutation, Q152X, in exon 5 of the VDR gene. Both mother and father were heterozygous for this mutation.
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tient. Biochemistry findings improved progressively during intermittent i.v. calcium therapy. A 5-day course of i.v. calcium treatment was administered 14 times during a 16-month period, during which time serum PTH and ALP levels returned to normal.
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tient is receiving only oral calcium (125 mg elemental calcium/ kg/day), and the most recent PTH level was 89 ng/l (normal range: 15–65 ng/l), and ALP 207 U/l (normal range 145–420 U/l).
(889 pg/ml) levels were still elevated. Moreover, he refused to take calcium tablets. Inpatient treatment was initiated with continuous i.v. infusion of calcium gluconate (50 mg elemental calcium/ kg/day) via a peripheral 22-gauge cannula for 5 consecutive days per month and 40 ng/kg/day calcitriol therapy at the age of 4 years. The cannula needed replacing on alternate days. A mild chemical burn was observed on only one occasion. The lesion, cleaned with 0.9% saline and alcohol regressed within a few days. Within 5 days of i.v. therapy, a significant decrease in the PTH level was observed. Calcium levels were maintained at approximately 9 mg/dl during i.v. therapy. After a 10-day stay in the hospital, he was discharged on oral calcium (40 mg/kg/day) and calcitriol (20 ng/kg/day). Following 12 months of i.v. therapy, there was significant improvement in clinical and radiological signs. A 5-day course of i.v. calcium treatment was administered 14 times during a 16- month period, during which time serum PTH and ALP levels returned to normal, and serial X-ray evaluation demonstrated a dramatic healing of the rickets (fig. 2, 3a), with shrinking of the cystic lesion of the humerus (fig. 3b). Marked acceleration in growth was seen and the patient gained a height of 8.5 cm (height SDS increasing to –1.82). However, there was no change in scalp hair (fig. 4). In view of the clinical improvement, intermittent i.v. calcium therapy was discontinued after 2 years when the boy was aged 5.8 years. During i.v. calcium treatment, a slight increase in urinary calcium creatinine ratio was observed, but there were no signs of nephrocalcinosis on renal ultrasound. After discontinuation of the intermittent i.v. calcium therapy, ALP and PTH levels slightly increased, so he was treated with i.v. calcium infusion twice during a 2-month period. Currently, the pa-
Our patient had a non-sense mutation in the LBD of the VDR gene. This mutation results in premature stop at codon 152, and causes a truncated receptor, and absent affinity to 1,25(OH)2D3. It also deletes a dimerization domain, which is essential for receptor binding to the VDR hormone response element. Mutations in the LBD may disrupt ligand binding or heterodimerization with RXR, or prevent coactivators from binding to the VDR and cause partial or total hormone resistance. Premature stop mutations are severe. The same mutation was previously identified by Kristjansson et al. [13], but this report did not give detailed information of the phenotypic features of their patient. Patients with non-sense mutations with introduced premature stop signals have both total hormone resistance and alopecia [4]. Our patient had total alopecia. Mutations of the LBD are associated with variable degrees of vitamin D resistance and alopecia because of gen-
Successful Calcium Treatment in a Patient with HVDRR and Alopecia
Horm Res Paediatr 2015;83:67–72 DOI: 10.1159/000367711
Discussion
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Fig. 2. Serial biochemistry values of the pa-
a
Before treatment
At the end of the first year of treatment
At the end of the 2nd year of treatment
Fig. 3. a The X-rays of the patient show
b
Before treatment
otype-phenotype variability. Patients with alopecia generally have a more severe resistance to therapy than those without alopecia [1, 5]. Our patient did not respond initially to oral calcium and high-dose calcitriol. However, his serum chemistry and bone abnormalities were reversed by intermittent i.v. calcium therapy. Normalization of the biochemistry and X-rays took approximately 28 months of i.v. therapy, with healing of the rickets and reversal of secondary hyperparathyroidism and hypophosphatemia. The suppression of hyperparathyroidism with calcium supplementation alone indicates that the major defect in HVDRR is an inability to absorb calcium in the gastrointestinal tract [1, 9, 14]. Our patient exhibited the classical clinical pattern of HVDRR such as metaphyseal widening of the wrist and ankles, and bowing of the lower extremities [1, 5]. He was also growth retarded as demonstrated by most patients with HVDRR [9]. He had hypocalcemia, elevated ALP, 70
Horm Res Paediatr 2015;83:67–72 DOI: 10.1159/000367711
After 28 months of treatment
and secondary hyperparathyroidism. Despite the latter, the serum phosphorus level was only at the lower limit of the normal range, in line with previous studies showing that serum phosphorus level may be within the normal range in some patients with HVDRR with non-sense mutations [15, 16]. As demonstrated in our patient, children with HVDRR do not usually require phosphorus supplementation [1, 9]. An interesting aspect in this case of HVDRR is that while the patient had severe rickets, as well as alopecia, the biochemistry findings were less severe than one would expect for the clinical findings. Several studies have reported i.v. calcium therapy to achieve normal serum calcium levels and healing of the rickets [1, 7, 10]. Most patients with HVDRR require prolonged hospitalization for i.v. calcium therapy in order to maintain normocalcemia. Additionally, placement of a central port is required for long-term administration of i.v. calcium. Unfortunately, i.v. calcium therErsoy/Kiremitci/Isojima/Kitanaka
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progressive healing of rickets with intermittent i.v. calcium therapy. b The cystic lesion on the humerus. The cystic lesion on the humerus shrunk after intermittent i.v. calcium therapy.
Color version available online
Fig. 4. Patient with alopecia. There was no change in alopecia during intermittent i.v. calcium therapy.
apy can cause complications such as central line infection due to indwelling catheters and, often nosocomial infections leading to prolonged hospitalizations [2, 9]. Owing to previously reported complications of the therapy [2, 9], i.v. calcium therapy was administered via a peripheral cannula to our patient, with a pattern of short-term (4 h), and intermittent (5 consecutive days per month)
infusions. No catheter was inserted during infusion. When extravasation of a calcium gluconate infusion occurs, there may be rapid and marked swelling and erythema, with signs of soft-tissue necrosis or infection, and ensuing extensive local calcification, called calcinosis cutis [17]. Extravasation of calcium gluconate occurred only once in our patient, leading to slight local tissue necrosis which regressed within several days. In a previous study, some children with HVDRR were managed with intermittent i.v. calcium regimens using oral calcium during intervals. However, infection as a complication occurred due to prolonged hospitalization (4.5 months), and the central port for i.v. calcium therapy [2]. In the literature, there is no report of any patients with HVDRR being administered i.v. calcium via a peripheral cannula. Malloy et al. [2] reported three important clinical concepts in an HVDRR patient treated with i.v. calcium. Firstly, the PTH is again elevated prior to the next infusion. We also observed similar results in our patient, but PTH levels decreased progressively during 28 months. Secondly, the risk for nephrocalcinosis increased due to elevated urinary calcium at the end of the infusion. Despite slightly elevated urinary calcium levels, nephrocalcinosis did not develop. Thirdly, during the early course of i.v. calcium therapy, serum phosphorus is suppressed. As mentioned earlier, serum phosphorus levels in our patients were not suppressed. In conclusion, we described a patient with HVDRR with a non-sense mutation in the LBD of the VDR gene and alopecia. Despite alopecia and findings of severe rickets, the patient was successfully treated with short-term i.v. calcium infusion without a central catheter, prolonged hospitalization or development of nephrocalcinosis.
Disclosure Statement There is no conflict of interest.
1 Malloy PJ, Pike JW, Feldman D: The vitamin D receptor and the syndrome of hereditary 1,25 dihydroxy vitamin D-resistant rickets. Endocr Rev 1999;20:156–188. 2 Malloy PJ, Wang J, Srivastava T, Feldman D: Hereditary 1,25-dihydroxyvitamin D-resistant rickets with alopecia resulting from a novel missense mutation in the DNA-binding domain of the vitamin D receptor. Mol Genet Metab 2010; 99: 72–79.
Successful Calcium Treatment in a Patient with HVDRR and Alopecia
3 Al-Khenaizan S, Vitale P: Vitamin D-dependent rickets type II with alopecia: two case reports and review of the literature. Int J Dermatol 2003;42:682–685. 4 Malloy PJ, Feldman D: The role of vitamin D receptor mutations in the development of alopecia. Mol Cell Endocrinol 2011; 347: 90– 96. 5 Malloy PJ, Feldman D: Genetic disorders and defects in vitamin D action. Endocrinol Metab Clin North Am 2010; 39: 333–346.
6 Kittaka A, Kurihara M, Suhara Y, Takayama H: 2a-(3-hydroxypropyl)- and 2a-(3hydroxypropoxy)-1a,25-dihydroxyvitamin D3 accessible to vitamin D receptor mutant related to hereditary vitamin D-resistant rickets. Chem Pharm Bull 2003;51:357–358. 7 Al-Aqeel A, Ozand P, Sobki S, Sewairi W, Marx S: The combined use of intravenous and oral calcium for the treatment of vitamin D dependent rickets type II (VDDRII). Clin Endocrinol (Oxf) 1993;39:229–237.
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11 Huang K, Malloy P, Feldman D, Pitukcheewanont P: Enteral calcium infusion used successfully as treatment for a patient with hereditary vitamin D resistant rickets (HVDRR) without alopecia: a novel mutation. Gene 2012;512:554–559. 12 Neyzi O, Furman A, Bundak R, Bundak R, Gunoz H, Darendeliler F, Bas F: Growth references for Turkish children aged 6 to 18 years. Acta Paediatr 2006;95:1635–1641. 13 Kristjansson K, Rut AR, Hewison M, O’Riordan JL, Hughes MR: Two mutations in the hormone binding domain of the vitamin D receptor cause tissue resistance to 1, 25 dihydroxyvitamin D3. J Clin Invest 1993; 92: 12–16. 14 Chaturverdi D, Garabedian M, Carel JC, Léger J: Different mechanisms of intestinal calcium absorption at different life stages: therapeutic implications and long-term responses to treatment in patients with hereditary vitamin D-resistant rickets. Horm Res Paediatr 2012;78:326–331.
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15 Tiosano D, Schwartz Y, Braver Y, Hadash A, Gepstein V: The renin-angiotensin system, blood pressure, and heart structure in patients with hereditary vitamin D-resistance rickets (HVDRR). J Bone Miner Res 2011; 26: 2252– 2260. 16 Malloy PJ, Hochberg Z, Tiosano D, Pike JW, Hughes MR: The molecular basis of hereditary 1,25-dihydroxyvitamin D3 resistant rickets in seven related families. J Clin Invest 1990;86:2071–2079. 17 Celbek G, Gungor A, Albayrak H, Kir S, Guvenc SC, Aydin Y: Bullous skin reaction seen after extravasation of calcium gluconate. Clin Exp Dermatol 2013;38:154–155.
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8 Sakati N, Woodhouse NJ, Niles N, Harfi H, de Grange DA: Hereditary resistance to 1,25-dihydroxyvitamin D: clinical and radiological improvement during high-dose oral calcium therapy. Horm Res 1986;24:280–287. 9 Ma NS, Malloy PJ, Pitukcheewanont P, Dreimane D, Geffner ME: Hereditary vitamin D resistant rickets: identification of a novel splice site mutation in the vitamin D receptor gene and successful treatment with oral calcium therapy. Bone 2009;45:743–746. 10 Balsan S, Garabédian M, Larchet M, Gorski AM, Cournot G, et al: Long-term nocturnal calcium infusions can cure rickets and promote normal mineralization in hereditary resistance to 1,25-dihydroxyvitamin D. J Clin Invest 1986;77:1661–1667.
HOR MON E RE SE ARCH I N PÆDIATRIC S
Horm Res Paediatr 2015;83:67–72 DOI: 10.1159/000367711
Received: April 7, 2014 Accepted: August 18, 2014 Published online: January 6, 2015
Successful Intermittent Intravenous Calcium Treatment via the Peripheral Route in a Patient with Hereditary Vitamin D-Resistant Rickets and Alopecia Betul Ersoy a Seniha Kiremitci a Tsuyoshi Isojima b Sachiko Kitanaka b a b
Division of Pediatric Endocrinology and Metabolism, Celal Bayar University, School of Medicine, Manisa, Turkey; Department of Pediatrics, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
Established Facts • Hereditary vitamin D-resistant rickets (HVDRR) is a disorder with different biochemical and clinical features caused by different defects within vitamin D receptor gene. • Effective treatment of HVDRR is still controversial.
Novel Insights
Key Words Hereditary vitamin D-resistant rickets · Vitamin D receptor · Intermittent peripheral i.v. calcium therapy
Abstract Background: Hereditary vitamin D-resistant rickets (HVDRR) is a rare genetic disorder caused by mutations in the vitamin D receptor (VDR) gene, which result in end-organ resistance to 1,25-(OH)2D3. Patients with HVDRR are mostly treated using i.v. calcium therapy with a central catheter. However, central catheter-related complications have been reported. Patient: The patient was a 3-year-old boy presenting with
© 2015 S. Karger AG, Basel 1663–2818/15/0831–0067$39.50/0 E-Mail [email protected] www.karger.com/hrp
waddling gait and alopecia. He had hypocalcemia [8 mg/dl (2 mmol/l)], hyperparathyroidism (1,232 ng/l), and elevated 1,25-(OH)2D3 levels (>250 pmol/l). DNA sequence analyses of the VDR gene showed a homozygous C–T transition at codon 152, resulting in a non-sense mutation in exon 5. Interventions and Outcomes: The patient was initially treated with calcitriol (80 ng/kg/day) and high-dose oral calcium (150 mg/kg/day) for one year. At the end of the first year, intermittent (5 days per month) i.v. calcium therapy without a central catheter was initiated because of insufficient clinical and radiological improvement. After 2 years of intermittent i.v. calcium therapy, there was a clear improvement based on clinical progress and on X-ray and biochemical findings. No
Seniha Kiremitci, MD Celal Bayar University, School of Medicine Uncubozköy Mahallesi, Mimar Sinan Bulvarı TR–45030 Manisa (Turkey) E-Mail senihakiremitci @ yahoo.com
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• We report the phenotypic features of a patient with HVDRR linked with homozygous C–T transition at codon 152, in exon 5 of the vitamin D receptor gene, which was previously described. • The patient was treated successfully with i.v. calcium via a peripheral line using a novel method (5 consecutive days a month) without any complications or adverse effects.
Introduction
The rare recessive genetic disease hereditary vitamin D-resistant rickets (HVDRR) is caused by mutations in the vitamin D receptor (VDR) gene which results in endorgan resistance to the 1,25-(OH)2D3 action. The major defect caused by the mutant VDR gene is a decrease in intestinal calcium and phosphate absorption, which leads to decreased bone mineralization, and rickets [1]. Some patients also have total body alopecia [1, 2]. Alopecia has been thought to be associated with increased severity of the disease, although there have also been severe cases without alopecia [3, 4]. Several different types of mutations, such as non-sense mutations, insertions/substitutions, insertions/duplications, deletions, and splice site mutations have been identified in the VDR gene as the cause of HVDRR [5]. Most of these mutations occur at the DNA-binding domain (DBD) of the VDR, but few are located at the ligand-binding domain (LBD) [6]. Many patients with mutations in the DBD have alopecia [5]. Treatment for patients with HVDRR is not standardized. Studies have shown successful treatment results with i.v. [7] and/or oral calcium therapy [8, 9]. However, i.v. calcium therapy requires a central catheter and prolonged hospitalization [10]. One report has described successful therapy with enteral calcium using a nasogastric tube [11]. To our knowledge, there are no studies to date in which peripheral administration of i.v. calcium has been used. In this report, we describe a patient with a homozygous non-sense mutation in the LBD of the VDR gene, which resulted in the syndrome of HVDRR with alopecia. We also demonstrate the success of intermittent i.v. calcium therapy without the need for prolonged hospitalization. Case Description A 3.4-year-old male patient presenting with gait disorder, was admitted to our Pediatric Endocrinology and Metabolism outpatient clinic. He was born full term via normal spontaneous vaginal delivery, with a birth weight of 3.3 kg, and no complications. Birth
68
Horm Res Paediatr 2015;83:67–72 DOI: 10.1159/000367711
length and head circumference are not known. Alopecia was noted at birth. His mother’s pregnancy was uncomplicated. He is the first child of a nonconsanguineous Turkish family from the western part of Turkey. He received prophylactic vitamin D supplements from the age of 14 days to one year. At presentation, his height was 90 cm, height standard deviation score (SDS) was –2.08 and the weight was 12.5 kg (SDS: –1.9) according to national growth data [12]. Examination showed no scalp hair, scanty eyebrows and eyelashes, metaphyseal widening of his wrist and ankles, and bowing of his upper and lower extremities. He had a waddling gait and could not maintain his balance while walking. The initial biochemistry revealed a serum total calcium level of 8.0 mg/dl (normal range: 8.1–10.4 mg/dl), inorganic phosphorus 3.8 mg/dl (normal range: 2.5–4.5 mg/dl), alkaline phosphatase (ALP) 661 U/l (normal range: 145–420 U/l), and parathyroid hormone (PTH) 1,232 ng/l (normal range: 15–65 ng/l). His 25(OH)D level was 21 ng/ml (normal range: 9–37 ng/ml), and the 1,25(OH)2D3 was greatly elevated at >250 pmol/l (normal range: 39–102 pmol/l). The urine calcium to creatinine ratio was low at 0.02 (normal range: 0.05–0.2). Wrist X-ray revealed cupping and fraying of the metaphysis, and widening of the epiphysis. A skeletal survey showed a cystic lesion and a fracture in the upper part of the humerus due to hyperparathyroidism. While the initial biochemistry was suggestive of nutritional rickets, the elevated 1,25(OH)2D3 levels and the severity of rickets both clinically and radiologically raised the suspicion of a possible HVDRR. After obtaining informed consent from the parents, this diagnosis was subsequently confirmed by DNA sequencing. Genetic Analysis The study was performed with the approval from the Ethics Committee of The University of Tokyo and Celal Bayar University Faculty of Medicine. Genomic DNA was isolated from the peripheral blood at the genetic laboratories of Celal Bayar University Faculty of Medicine. The entire coding region and exonintron boundaries of the VDR gene were amplified from genomic DNA by polymerase chain reaction (PCR), using designed PCR primers. Information on the PCR primers and the PCR conditions will be provided on request. Subsequently, PCR products were sequenced using an ABI Prism BigDye Terminator Cycle Sequencing Ready Reaction Kit (PE Applied Biosystems, Foster City, Calif., USA), and the forward and reverse primers from the PCR amplification. Direct sequencing in both directions was performed on an autosequencer (PE for consistency Applied Biosystems 3130x1, Genetic Analyzer). Q152X, the VDR gene at exon 5 homozygous mutation was identified. The patient was found to have a homozygous C–T 140 transition at codon 152, resulting in a non-sense mutation, Q152X, in exon 5 of the VDR gene. Both parents were found to be heterozygous for this mutation (fig. 1). Clinical and biochemical analyses of the parents were normal. Treatment The patient was initially treated with calcitriol (80 ng/kg/day) and high-dose oral calcium (150 mg/kg/day) for one year. During the first year of treatment, the patient showed no improvement in the clinical, laboratory and radiological findings. His height velocity was 4 cm per year, and his height SDS fell to –2.46. Laboratory findings showed that the ALP (585 U/l) and PTH 148
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peripheral complications were reported either. Conclusion: HVDRR with a non-sense mutation in the ligand-binding domain and alopecia was successfully treated with intermittent i.v. calcium without a central catheter. © 2015 S. Karger AG, Basel
Fig. 1. DNA sequence of the patient, his father and mother in the VDR gene. The patient has a homozygous C–T transition at codon 152, resulting in a non-sense mutation, Q152X, in exon 5 of the VDR gene. Both mother and father were heterozygous for this mutation.
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tient. Biochemistry findings improved progressively during intermittent i.v. calcium therapy. A 5-day course of i.v. calcium treatment was administered 14 times during a 16-month period, during which time serum PTH and ALP levels returned to normal.
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tient is receiving only oral calcium (125 mg elemental calcium/ kg/day), and the most recent PTH level was 89 ng/l (normal range: 15–65 ng/l), and ALP 207 U/l (normal range 145–420 U/l).
(889 pg/ml) levels were still elevated. Moreover, he refused to take calcium tablets. Inpatient treatment was initiated with continuous i.v. infusion of calcium gluconate (50 mg elemental calcium/ kg/day) via a peripheral 22-gauge cannula for 5 consecutive days per month and 40 ng/kg/day calcitriol therapy at the age of 4 years. The cannula needed replacing on alternate days. A mild chemical burn was observed on only one occasion. The lesion, cleaned with 0.9% saline and alcohol regressed within a few days. Within 5 days of i.v. therapy, a significant decrease in the PTH level was observed. Calcium levels were maintained at approximately 9 mg/dl during i.v. therapy. After a 10-day stay in the hospital, he was discharged on oral calcium (40 mg/kg/day) and calcitriol (20 ng/kg/day). Following 12 months of i.v. therapy, there was significant improvement in clinical and radiological signs. A 5-day course of i.v. calcium treatment was administered 14 times during a 16- month period, during which time serum PTH and ALP levels returned to normal, and serial X-ray evaluation demonstrated a dramatic healing of the rickets (fig. 2, 3a), with shrinking of the cystic lesion of the humerus (fig. 3b). Marked acceleration in growth was seen and the patient gained a height of 8.5 cm (height SDS increasing to –1.82). However, there was no change in scalp hair (fig. 4). In view of the clinical improvement, intermittent i.v. calcium therapy was discontinued after 2 years when the boy was aged 5.8 years. During i.v. calcium treatment, a slight increase in urinary calcium creatinine ratio was observed, but there were no signs of nephrocalcinosis on renal ultrasound. After discontinuation of the intermittent i.v. calcium therapy, ALP and PTH levels slightly increased, so he was treated with i.v. calcium infusion twice during a 2-month period. Currently, the pa-
Our patient had a non-sense mutation in the LBD of the VDR gene. This mutation results in premature stop at codon 152, and causes a truncated receptor, and absent affinity to 1,25(OH)2D3. It also deletes a dimerization domain, which is essential for receptor binding to the VDR hormone response element. Mutations in the LBD may disrupt ligand binding or heterodimerization with RXR, or prevent coactivators from binding to the VDR and cause partial or total hormone resistance. Premature stop mutations are severe. The same mutation was previously identified by Kristjansson et al. [13], but this report did not give detailed information of the phenotypic features of their patient. Patients with non-sense mutations with introduced premature stop signals have both total hormone resistance and alopecia [4]. Our patient had total alopecia. Mutations of the LBD are associated with variable degrees of vitamin D resistance and alopecia because of gen-
Successful Calcium Treatment in a Patient with HVDRR and Alopecia
Horm Res Paediatr 2015;83:67–72 DOI: 10.1159/000367711
Discussion
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Fig. 2. Serial biochemistry values of the pa-
a
Before treatment
At the end of the first year of treatment
At the end of the 2nd year of treatment
Fig. 3. a The X-rays of the patient show
b
Before treatment
otype-phenotype variability. Patients with alopecia generally have a more severe resistance to therapy than those without alopecia [1, 5]. Our patient did not respond initially to oral calcium and high-dose calcitriol. However, his serum chemistry and bone abnormalities were reversed by intermittent i.v. calcium therapy. Normalization of the biochemistry and X-rays took approximately 28 months of i.v. therapy, with healing of the rickets and reversal of secondary hyperparathyroidism and hypophosphatemia. The suppression of hyperparathyroidism with calcium supplementation alone indicates that the major defect in HVDRR is an inability to absorb calcium in the gastrointestinal tract [1, 9, 14]. Our patient exhibited the classical clinical pattern of HVDRR such as metaphyseal widening of the wrist and ankles, and bowing of the lower extremities [1, 5]. He was also growth retarded as demonstrated by most patients with HVDRR [9]. He had hypocalcemia, elevated ALP, 70
Horm Res Paediatr 2015;83:67–72 DOI: 10.1159/000367711
After 28 months of treatment
and secondary hyperparathyroidism. Despite the latter, the serum phosphorus level was only at the lower limit of the normal range, in line with previous studies showing that serum phosphorus level may be within the normal range in some patients with HVDRR with non-sense mutations [15, 16]. As demonstrated in our patient, children with HVDRR do not usually require phosphorus supplementation [1, 9]. An interesting aspect in this case of HVDRR is that while the patient had severe rickets, as well as alopecia, the biochemistry findings were less severe than one would expect for the clinical findings. Several studies have reported i.v. calcium therapy to achieve normal serum calcium levels and healing of the rickets [1, 7, 10]. Most patients with HVDRR require prolonged hospitalization for i.v. calcium therapy in order to maintain normocalcemia. Additionally, placement of a central port is required for long-term administration of i.v. calcium. Unfortunately, i.v. calcium therErsoy/Kiremitci/Isojima/Kitanaka
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progressive healing of rickets with intermittent i.v. calcium therapy. b The cystic lesion on the humerus. The cystic lesion on the humerus shrunk after intermittent i.v. calcium therapy.
Color version available online
Fig. 4. Patient with alopecia. There was no change in alopecia during intermittent i.v. calcium therapy.
apy can cause complications such as central line infection due to indwelling catheters and, often nosocomial infections leading to prolonged hospitalizations [2, 9]. Owing to previously reported complications of the therapy [2, 9], i.v. calcium therapy was administered via a peripheral cannula to our patient, with a pattern of short-term (4 h), and intermittent (5 consecutive days per month)
infusions. No catheter was inserted during infusion. When extravasation of a calcium gluconate infusion occurs, there may be rapid and marked swelling and erythema, with signs of soft-tissue necrosis or infection, and ensuing extensive local calcification, called calcinosis cutis [17]. Extravasation of calcium gluconate occurred only once in our patient, leading to slight local tissue necrosis which regressed within several days. In a previous study, some children with HVDRR were managed with intermittent i.v. calcium regimens using oral calcium during intervals. However, infection as a complication occurred due to prolonged hospitalization (4.5 months), and the central port for i.v. calcium therapy [2]. In the literature, there is no report of any patients with HVDRR being administered i.v. calcium via a peripheral cannula. Malloy et al. [2] reported three important clinical concepts in an HVDRR patient treated with i.v. calcium. Firstly, the PTH is again elevated prior to the next infusion. We also observed similar results in our patient, but PTH levels decreased progressively during 28 months. Secondly, the risk for nephrocalcinosis increased due to elevated urinary calcium at the end of the infusion. Despite slightly elevated urinary calcium levels, nephrocalcinosis did not develop. Thirdly, during the early course of i.v. calcium therapy, serum phosphorus is suppressed. As mentioned earlier, serum phosphorus levels in our patients were not suppressed. In conclusion, we described a patient with HVDRR with a non-sense mutation in the LBD of the VDR gene and alopecia. Despite alopecia and findings of severe rickets, the patient was successfully treated with short-term i.v. calcium infusion without a central catheter, prolonged hospitalization or development of nephrocalcinosis.
Disclosure Statement There is no conflict of interest.
1 Malloy PJ, Pike JW, Feldman D: The vitamin D receptor and the syndrome of hereditary 1,25 dihydroxy vitamin D-resistant rickets. Endocr Rev 1999;20:156–188. 2 Malloy PJ, Wang J, Srivastava T, Feldman D: Hereditary 1,25-dihydroxyvitamin D-resistant rickets with alopecia resulting from a novel missense mutation in the DNA-binding domain of the vitamin D receptor. Mol Genet Metab 2010; 99: 72–79.
Successful Calcium Treatment in a Patient with HVDRR and Alopecia
3 Al-Khenaizan S, Vitale P: Vitamin D-dependent rickets type II with alopecia: two case reports and review of the literature. Int J Dermatol 2003;42:682–685. 4 Malloy PJ, Feldman D: The role of vitamin D receptor mutations in the development of alopecia. Mol Cell Endocrinol 2011; 347: 90– 96. 5 Malloy PJ, Feldman D: Genetic disorders and defects in vitamin D action. Endocrinol Metab Clin North Am 2010; 39: 333–346.
6 Kittaka A, Kurihara M, Suhara Y, Takayama H: 2a-(3-hydroxypropyl)- and 2a-(3hydroxypropoxy)-1a,25-dihydroxyvitamin D3 accessible to vitamin D receptor mutant related to hereditary vitamin D-resistant rickets. Chem Pharm Bull 2003;51:357–358. 7 Al-Aqeel A, Ozand P, Sobki S, Sewairi W, Marx S: The combined use of intravenous and oral calcium for the treatment of vitamin D dependent rickets type II (VDDRII). Clin Endocrinol (Oxf) 1993;39:229–237.
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