Acta Neurol Belg DOI 10.1007/s13760-014-0405-9
LETTER TO THE EDITOR
A novel NTRK1 mutation in a patient with congenital insensitivity to pain with anhidrosis Uluc¸ Yis¸ • Ine`s Mademan • Salih Kavukc¸u Jonathan Baets
•
Received: 25 October 2014 / Accepted: 4 December 2014 Ó Belgian Neurological Society 2014
Congenital insensitivity to pain with anhidrosis (CIPA), also known as Hereditary Sensory and Autonomic Neuropathy type IV (HSAN IV), is a rare autosomal recessive disorder which affects the peripheral nervous system. CIPA is caused by mutations in the NTRK1 gene located on chromosome 1 (1q21-q22) [1]. Mutations cause a loss of function with subsequent failure of Trk-A/ß-NGF signaling. In this report, we describe the case of a Turkish patient with CIPA with a novel homozygous mutation in NTRK1 gene. The patient is a 7-year-old male, who was diagnosed clinically with CIPA at the age of 10 months while being investigated for episodes of high fever and anhidrosis. He had history of numerous hospitalizations due to fever of unknown origin, chronic otitis media and febrile convulsion at the age of 6 months. Results of extensive examinations including karyotype, blood and urine amino acids,
U. Yis¸ (&) Division of Child Neurology, Department of Pediatrics, School of Medicine, Dokuz Eylu¨l University, Izmir, Turkey e-mail: [email protected] I. Mademan J. Baets Neurogenetics Group, VIB-Department of Molecular Genetics, Institute Born-Bunge, University of Antwerp, Antwerp, Belgium I. Mademan J. Baets Laboratory of Neurogenetics, Institute Born-Bunge, University of Antwerp, Antwerp, Belgium S. Kavukc¸u Division of Child Nephrology, Department of Pediatrics, School of Medicine, Dokuz Eylu¨l University, Izmir, Turkey J. Baets Department of Neurology, Antwerp University Hospital, Antwerp, Belgium
TANDEM mass spectrometry, urinary organic acids, uric acid, lactate, pyruvate, ammonia, humoral and cellular immunity, ophthalmic examination, electromyography, brain magnetic resonance imaging and gene analysis for familial Mediterranean fever all were normal. He also had surgery for a tibial fracture that occurred after falling while playing at the age of 5 years. He had a prior history of multiple fractures of the tibia and ankles. These were after minor trauma and there were no signs of pain subsequent to these fractures. Examination at the age of 7 years revealed wide-based ataxic gait, severely delayed speech (produced only simple single words), absent corneal reflex, tongue bleeding due to self-inflicted bites, eczematous lesions in skin folds, generalized xerosis and hyperkeratosis in palms and soles (Fig. 1). Genomic DNA was extracted from peripheral blood, obtained from the patient and his parents after informed consent. We analyzed NTRK1 in a genomic DNA sample of the Turkish CIPA patient and discovered a novel homozygous splice-site variation c.2206-11G[A. Segregation analysis revealed that both his asymptomatic parents were heterozygous carriers. To evaluate the consequences of the c.2206-11G[A mutation on splicing, we extracted mRNA from lymphoblasts derived from the patient and his parents and reverse transcribed it into cDNA; subsequent sequencing revealed an intron retention of 9 base pairs. As a consequence, at the predicted protein level this alteration results in an in-frame insertion of 3 amino acids (Trp, Pro and Gln) between exon 16 and 17 creating a slightly larger protein (Fig. 2a, b). CIPA is an autosomal recessive condition characterized by a wide spectrum of clinical symptoms. The clinical signs are generally evident in neonates and infants presenting with apathy, hypotonia, feeding difficulties,
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Acta Neurol Belg
Fig. 1 Eczematous lesions in skin folds, generalized xerosis and hyperkeratosis in palms
frequent episodes of unexplained hyperprexia and anhidrosis. Patients may also present with convulsions and coma due to heat stroke. Mild mental retardation and delay in motor developmental milestones may be observed and are considered an integral part of the phenotype. Growth retardation, biting and scarring of the lips and tongue, autoextraction of teeth, maxillofacial problems, dystrophic nails, corneal ulcers, complicated fractures, dislocations, neuropathic joints and infection necessitating amputation are also common. Immunodeficiency has been described as well in CIPA patients, possibly contributing to infectious complications of the disease [2]. CIPA is caused by recessive mutatuions in NTRK1, leading to a loss of function of the neurotrophic tyrosine kinase receptor (Trk-A). Trk-A is phosphorylated in response to nerve growth factor ß (NGFB). The survival of
A
B
Fig. 2 a Segregation analysis of the identified mutation in family CMT-1038. Patient CMT-1038.01 has the c.2206-11G[A mutation [p.Glu735_Ala736insTrpProGln] in homozygous state. Both unaffected parents are heterozygous carriers. b Primer design for mRNA studies. The intronic c.2206-11G[A mutation resides 11 bp from exon 17. To confirm the in silico-predicted effects on splicing caused
123
by this mutation, lymphoblast mRNA was transcribed to c.DNA and assayed using two different primer pairs. Primer pair 1 contains a forward primer in exon 15 and reverse primer situated on the exon 16–17 boundary. Primer pair 2 contains a forward primer located in exon 14 and reverse primer in exon 17. Ex, exon; asterisk, stop codon
Acta Neurol Belg
the sympathetic ganglion neurons and nociceptive sensory neurons in the dorsal root ganglions is dependent on NGFB [1, 3]. Therefore, NTRK1 mutations lead to the absence of small-diameter afferent neurons and sympathetic neuron innervation of sweat glands. Limited cases have been reported from Turkish population. One report with six families from Northern Central Turkey with different mutations in the NTRK1 gene was reported in 2008 [4]. All patients were products of consanguineous families. NTRK1 mutation screening demonstrated one novel frameshift mutation [exon 3 (c.353_359 ? 2TdelGTCGCCTGT)], two novel nonsense mutations [exon 5 (c.496G[T; p.Gly166X) and exon 17 (c.2308C[T; p.Gln770X)] and three unrelated kindreds with the same splice-site mutation [exon 14 (c.1633-1G[T)]. These three patients were unrelated though they originated from the same geographic area. Loss of heterozygosity was observed in these cases and they shared the same haplotype across a 6-Mbp region on chromosome 1. This finding suggested a founder effect within the Turkish population. Founder mutations of NTRK1 gene have also been described in Japanese and Israeli-Negev Bedouin populations [5, 6]. Interestingly, the three patients carrying the same mutation had different clinical findings without genotype–phenotype correlation. However, the clinical variability of the CIPA phenotype is thought to be fairly limited compared to that of other subtypes of inherited peripheral neuropathy. The parents of our case were not known to be consanguineous and the patient had a novel homozygous splice-site mutation c.2206-11G[A [p.Glu735_Ala736insTrpProGln] in the NTRK1 gene. Both of his parents were in good health and were heterozygous mutation carriers. In conclusion, CIPA is a rare autosomal recessive disorder and should be considered in the differential diagnosis of children with episodes of hyperprexia, anhidrosis, developmental delay and self-mutilating behavior. As this clinical syndrome is stereotypical in most patients and also given the fact that CIPA is genetically fairly homogeneous,
NTRK1 mutation screening should be initiated in all CIPA patients. Acknowledgments We would like to thank the family for their willingness to participate in this study. The work was funded in part by the Association Belge contre les Maladies Neuromusculaires (ABMM), the agency for Innovation by Science and Technology (IWT), the Fund for Scientific Research Flanders (FWO-Flanders) and the European Community’s Seventh Framework Programme (FP7/2007–2013) under grant agreement number 2012–305121,’’ Integrated European—omics research project for diagnosis and therapy in rare neuromuscular and neurodegenerative diseases (NEUROMICS)’’. Conflict of interest The authors declared no potential conflicts of interest with respect to the search, authorship, and/or publication of this article.
References 1. Indo Y, Tsuruta M, Hayashida Y et al (1996) Mutations in the TRKA/NGF receptor gene in patients with congenital insensitivity to pain with anhidrosis. Nat Genet 13:485–488 2. Kilic SS, Ozturk R, Sarisozen B, Rotthier A, Baets J, Timmerman V (2009) Humoral immunodeficiency in congenital insensitivity to pain with anhidrosis. Neurogenetics 10:161–165 3. Beigelman A, Levy J, Hadad N et al (2009) Abnormal neutrophil chemotactic activity in children with congenital insensitivity to pain with anhidrosis (CIPA): the role of nerve growth factor. Clin Immunol 130:365–372 4. Tu¨ysu¨z B, Bayrakli F, DiLuna ML et al (2008) Novel NTRK1 mutations cause hereditary sensory and autonomic neuropathy type IV: demonstration of a founder mutation in the Turkish population. Neurogenetics 9:119–125 5. Miura Y, Mardy S, Awaya Y et al (2000) Mutation and polymorphism analysis of the TRKA (NTRK1) gene encoding a high-affinity receptor for nerve growth factor in congenital insensitivity to pain with anhidrosis (CIPA) families. Hum Genet 106:116–124 6. Shatzky S, Moses S, Levy J et al (2000) Congenital insensitivity to pain with anhidrosis (CIPA) in Israeli-Bedouins: genetic heterogeneity, novel mutations in the TRKA/NGF receptor gene, clinical findings, and results of nerve conduction studies. Am J Med Genet 92:353–360
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LETTER TO THE EDITOR
A novel NTRK1 mutation in a patient with congenital insensitivity to pain with anhidrosis Uluc¸ Yis¸ • Ine`s Mademan • Salih Kavukc¸u Jonathan Baets
•
Received: 25 October 2014 / Accepted: 4 December 2014 Ó Belgian Neurological Society 2014
Congenital insensitivity to pain with anhidrosis (CIPA), also known as Hereditary Sensory and Autonomic Neuropathy type IV (HSAN IV), is a rare autosomal recessive disorder which affects the peripheral nervous system. CIPA is caused by mutations in the NTRK1 gene located on chromosome 1 (1q21-q22) [1]. Mutations cause a loss of function with subsequent failure of Trk-A/ß-NGF signaling. In this report, we describe the case of a Turkish patient with CIPA with a novel homozygous mutation in NTRK1 gene. The patient is a 7-year-old male, who was diagnosed clinically with CIPA at the age of 10 months while being investigated for episodes of high fever and anhidrosis. He had history of numerous hospitalizations due to fever of unknown origin, chronic otitis media and febrile convulsion at the age of 6 months. Results of extensive examinations including karyotype, blood and urine amino acids,
U. Yis¸ (&) Division of Child Neurology, Department of Pediatrics, School of Medicine, Dokuz Eylu¨l University, Izmir, Turkey e-mail: [email protected] I. Mademan J. Baets Neurogenetics Group, VIB-Department of Molecular Genetics, Institute Born-Bunge, University of Antwerp, Antwerp, Belgium I. Mademan J. Baets Laboratory of Neurogenetics, Institute Born-Bunge, University of Antwerp, Antwerp, Belgium S. Kavukc¸u Division of Child Nephrology, Department of Pediatrics, School of Medicine, Dokuz Eylu¨l University, Izmir, Turkey J. Baets Department of Neurology, Antwerp University Hospital, Antwerp, Belgium
TANDEM mass spectrometry, urinary organic acids, uric acid, lactate, pyruvate, ammonia, humoral and cellular immunity, ophthalmic examination, electromyography, brain magnetic resonance imaging and gene analysis for familial Mediterranean fever all were normal. He also had surgery for a tibial fracture that occurred after falling while playing at the age of 5 years. He had a prior history of multiple fractures of the tibia and ankles. These were after minor trauma and there were no signs of pain subsequent to these fractures. Examination at the age of 7 years revealed wide-based ataxic gait, severely delayed speech (produced only simple single words), absent corneal reflex, tongue bleeding due to self-inflicted bites, eczematous lesions in skin folds, generalized xerosis and hyperkeratosis in palms and soles (Fig. 1). Genomic DNA was extracted from peripheral blood, obtained from the patient and his parents after informed consent. We analyzed NTRK1 in a genomic DNA sample of the Turkish CIPA patient and discovered a novel homozygous splice-site variation c.2206-11G[A. Segregation analysis revealed that both his asymptomatic parents were heterozygous carriers. To evaluate the consequences of the c.2206-11G[A mutation on splicing, we extracted mRNA from lymphoblasts derived from the patient and his parents and reverse transcribed it into cDNA; subsequent sequencing revealed an intron retention of 9 base pairs. As a consequence, at the predicted protein level this alteration results in an in-frame insertion of 3 amino acids (Trp, Pro and Gln) between exon 16 and 17 creating a slightly larger protein (Fig. 2a, b). CIPA is an autosomal recessive condition characterized by a wide spectrum of clinical symptoms. The clinical signs are generally evident in neonates and infants presenting with apathy, hypotonia, feeding difficulties,
123
Acta Neurol Belg
Fig. 1 Eczematous lesions in skin folds, generalized xerosis and hyperkeratosis in palms
frequent episodes of unexplained hyperprexia and anhidrosis. Patients may also present with convulsions and coma due to heat stroke. Mild mental retardation and delay in motor developmental milestones may be observed and are considered an integral part of the phenotype. Growth retardation, biting and scarring of the lips and tongue, autoextraction of teeth, maxillofacial problems, dystrophic nails, corneal ulcers, complicated fractures, dislocations, neuropathic joints and infection necessitating amputation are also common. Immunodeficiency has been described as well in CIPA patients, possibly contributing to infectious complications of the disease [2]. CIPA is caused by recessive mutatuions in NTRK1, leading to a loss of function of the neurotrophic tyrosine kinase receptor (Trk-A). Trk-A is phosphorylated in response to nerve growth factor ß (NGFB). The survival of
A
B
Fig. 2 a Segregation analysis of the identified mutation in family CMT-1038. Patient CMT-1038.01 has the c.2206-11G[A mutation [p.Glu735_Ala736insTrpProGln] in homozygous state. Both unaffected parents are heterozygous carriers. b Primer design for mRNA studies. The intronic c.2206-11G[A mutation resides 11 bp from exon 17. To confirm the in silico-predicted effects on splicing caused
123
by this mutation, lymphoblast mRNA was transcribed to c.DNA and assayed using two different primer pairs. Primer pair 1 contains a forward primer in exon 15 and reverse primer situated on the exon 16–17 boundary. Primer pair 2 contains a forward primer located in exon 14 and reverse primer in exon 17. Ex, exon; asterisk, stop codon
Acta Neurol Belg
the sympathetic ganglion neurons and nociceptive sensory neurons in the dorsal root ganglions is dependent on NGFB [1, 3]. Therefore, NTRK1 mutations lead to the absence of small-diameter afferent neurons and sympathetic neuron innervation of sweat glands. Limited cases have been reported from Turkish population. One report with six families from Northern Central Turkey with different mutations in the NTRK1 gene was reported in 2008 [4]. All patients were products of consanguineous families. NTRK1 mutation screening demonstrated one novel frameshift mutation [exon 3 (c.353_359 ? 2TdelGTCGCCTGT)], two novel nonsense mutations [exon 5 (c.496G[T; p.Gly166X) and exon 17 (c.2308C[T; p.Gln770X)] and three unrelated kindreds with the same splice-site mutation [exon 14 (c.1633-1G[T)]. These three patients were unrelated though they originated from the same geographic area. Loss of heterozygosity was observed in these cases and they shared the same haplotype across a 6-Mbp region on chromosome 1. This finding suggested a founder effect within the Turkish population. Founder mutations of NTRK1 gene have also been described in Japanese and Israeli-Negev Bedouin populations [5, 6]. Interestingly, the three patients carrying the same mutation had different clinical findings without genotype–phenotype correlation. However, the clinical variability of the CIPA phenotype is thought to be fairly limited compared to that of other subtypes of inherited peripheral neuropathy. The parents of our case were not known to be consanguineous and the patient had a novel homozygous splice-site mutation c.2206-11G[A [p.Glu735_Ala736insTrpProGln] in the NTRK1 gene. Both of his parents were in good health and were heterozygous mutation carriers. In conclusion, CIPA is a rare autosomal recessive disorder and should be considered in the differential diagnosis of children with episodes of hyperprexia, anhidrosis, developmental delay and self-mutilating behavior. As this clinical syndrome is stereotypical in most patients and also given the fact that CIPA is genetically fairly homogeneous,
NTRK1 mutation screening should be initiated in all CIPA patients. Acknowledgments We would like to thank the family for their willingness to participate in this study. The work was funded in part by the Association Belge contre les Maladies Neuromusculaires (ABMM), the agency for Innovation by Science and Technology (IWT), the Fund for Scientific Research Flanders (FWO-Flanders) and the European Community’s Seventh Framework Programme (FP7/2007–2013) under grant agreement number 2012–305121,’’ Integrated European—omics research project for diagnosis and therapy in rare neuromuscular and neurodegenerative diseases (NEUROMICS)’’. Conflict of interest The authors declared no potential conflicts of interest with respect to the search, authorship, and/or publication of this article.
References 1. Indo Y, Tsuruta M, Hayashida Y et al (1996) Mutations in the TRKA/NGF receptor gene in patients with congenital insensitivity to pain with anhidrosis. Nat Genet 13:485–488 2. Kilic SS, Ozturk R, Sarisozen B, Rotthier A, Baets J, Timmerman V (2009) Humoral immunodeficiency in congenital insensitivity to pain with anhidrosis. Neurogenetics 10:161–165 3. Beigelman A, Levy J, Hadad N et al (2009) Abnormal neutrophil chemotactic activity in children with congenital insensitivity to pain with anhidrosis (CIPA): the role of nerve growth factor. Clin Immunol 130:365–372 4. Tu¨ysu¨z B, Bayrakli F, DiLuna ML et al (2008) Novel NTRK1 mutations cause hereditary sensory and autonomic neuropathy type IV: demonstration of a founder mutation in the Turkish population. Neurogenetics 9:119–125 5. Miura Y, Mardy S, Awaya Y et al (2000) Mutation and polymorphism analysis of the TRKA (NTRK1) gene encoding a high-affinity receptor for nerve growth factor in congenital insensitivity to pain with anhidrosis (CIPA) families. Hum Genet 106:116–124 6. Shatzky S, Moses S, Levy J et al (2000) Congenital insensitivity to pain with anhidrosis (CIPA) in Israeli-Bedouins: genetic heterogeneity, novel mutations in the TRKA/NGF receptor gene, clinical findings, and results of nerve conduction studies. Am J Med Genet 92:353–360
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