Clin Genet 2015: 88: 593–596 Printed in Singapore. All rights reserved
© 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd CLINICAL GENETICS doi: 10.1111/cge.12595
Letter to the Editor
Novel homozygous ALX4 mutation causing frontonasal dysplasia-2 in a patient with meningoencephalocele To the Editor: Mutations in ALX4 gene have been associated with skull ossification defects including symmetrical parietal
foramina (1). While ALX4 heterozygous loss-of-function has been associated with symmetrical parietal ossification defects with vertical transmission (2, 3),
Fig. 1. Frontal facial appearance of the proband at 5 months of age (a). 3-D computerized tomographic (CT) scan of proband at 1 day old showing microcranium, brachycephaly, hypertelorism and meningoencephalocele in the high convexity of the skull extruding from the enlarged parietal foramen (b). 3-D CT scan of proband at 13 months showing bone defects abnormalities on cranial bone plate (c). Brain CT scan of the proband at 13 months showing corpus callosum agenesis, widened interhemispheric fissure and an occipital paramedian line cyst, lateral ventricles poorly characterized and probable cortical dysplasia (d). Partial sequencing electropherogram of the ALX4 gene’s exon 1 using specific intronic primers (list available on request). Control shows the ALX4 normal DNA reference (NG_015809.1) and its respective amino acids below codons; proband shows ALX4 p.Gly69fsX112 (c.205delG) homozygous mutation with the representation of the first eight altered amino acids (underlined) before the stop codon created downstream (X112) caused by a G-deletion frameshift in both alleles; mother showing heterozygous deletion (displayed as reverse sequencing) (e). Genomic array data for chromosome 11p showing a 20.8 Mb region of homozygosity (purple bar) at chr11:30,776,678–51,563,636 (GRCh37/hg19), which encompassed ALX4 gene (f). Frontal facial appearance of the patient’s mother (g).
593
594
793C>T homozygous
Mutation in ALX4 gene Complementary molecular research
− − Kinked CC, hypoplasia of Kinked CC cerebellar vermis
+ Lipoma of CC
793C>T homozygous
673C>G homozygous
Normal Left accessory nipple
− − − − − Preauricular skin tags −
+ Alopecia + + + Large lobules −
MR/DD
− − + + + +
+ + + + + +
(IVS+1755_*1503del2388) homozygous
Borderline normal Facial hypertrichosis
− − − − − − −
− − + − + NE
+ − − +
+ − + +
c.503delC in exon 2 homozygous
Normal
+ Hypoplastic occipital lobe and occipital cleft thin isthmus of kinked CC
− + + + + − −
− − + + + +
+ + + +
−
Absent nasal bone
−
Aplasia of nasal bones, underdevelopment of maxillary bones + + + −
Kariminejad et al. (4, 8) F 8 years Iran CB
Alanay et al. (6) F 9 years Turkey Calvarial defect
M 6, 5 years Turkey Parietal foramina
Kayserili et al. (7)
M 8 years Turkey Calvarial defects, coronal synostosis
Kayserili et al. (5) case 2
+, present; −, absent; CB, cranium bifidum; CC, corpus callosum; DD, developmental delay; F, female; M, male; MR, mental retardation; NE, not evaluated. a Adapted and modified table from Kariminejad et al., (8).
MR/DD
Cognition Other
M 3 years Turkey CB, calvarial defects, ethmoid aplasia, coronal synostosis Facial skeletal defects Aplasia of nasal bones, underdevelopment of maxillary bones Hypertelorism + Telecanthus + Blepharophimosis + Upslanting palpebral − fissures Microphthalmia + Strabismus + Wide nasal bridge + Broad columella + Notched nares + Broad and depressed + nasal tip Broad philtrum + Sparse hair Alopecia Absent eyelashes + Absent eyebrows + Absent body hair + Ears abnormalities Low set, large ears Genitalia Bilateral cryptorchidism abnormalities Microcephaly + Brain abnormalities Lipoma of CC, partial CC agenesis, partial vermian agenesis
Sex Age at examination Country of origin Skull defects
Kayserili et al. (5) case 1
Table 1. Comparison between patients described in literature with ALX4 homozygous mutations and the case reported hereina
Affymetrix CytoScan HD SNP-array arr(1–22)×2,(XY)×1
+ Median parietal meningoencephalocele, CC agenesis, occipital paramedian line cyst, cortical dysplasia and lateral ventricles poorly characterized DD Umbilical hernia, dermatite, floppy infant c.205delG in exon 1 homozygous
+ Alopecia + + + Low set, large ears Bilateral cryptorchidism, hypospadia
− + + + + +
Posterior cleft palate, nasal bone hipoplasia and underdevelopment of maxillary bones + − + −
M 5 months Brazil Calvarian defects, enlarged parietal foramina
Present case
Letter to the Editor
Letter to the Editor homozygous mutations are associated with frontonasal dysplasia spectrum with alopecia and characteristic phenotype (4–8). In 2008, Kariminejad et al. (4) reported a patient with skull defects and alopecia in whom later a homozygous ALX4 mutation (c.503delC) was found (8). A homozygous ALX4 nonsense mutation (c.793C>T) was found in two patients with similar phenotype and intellectual disability, suggesting a novel malformation syndrome named frontonasal dysplasia-2 (FND-2, MIM #613451) (5). Another homozygous missense mutation (c.673C>G) in the ALX4 was described in a patient with mild facial phenotype, parietal foramina and brain malformation, but normal cognition (7). Here, we report on a Brazilian boy with a novel homozygous mutation in the ALX4 (c.207delG) causing FND-2 syndrome and parietal meningoencephalocele. The patient (Fig. 1a–d) is the second child of a young healthy mother and unknown father. He was born at 38 weeks gestation by cesarean section due to prenatal diagnosis of meningoencephalocele, weight 2795 g (−1 SD), length 48 cm (−1 SD), and head circumference (HC) uncharted. At 1 month, surgical resection of the meningoencephalocele was performed. The first genetic evaluation was at 5 months and his measurements were weight 4640 g (−3 SD), length 57.2 cm (−3 SD) and HC 32 cm (−3 SD). He presented with microsomia, microcephaly, total alopecia, hypertelorism, short palpebral fissures, bilateral horizontal nystagmus, depressed nasal bridge, bifid nasal tip, posterior medial palatine fissure, bilateral cryptorchidism, hypospadia, anteriorly placed anus, atopic dermatitis, hypotonia and severe neurodevelopmental delay. The three-dimensional craniofacial computerized tomographic scan (3-D CT) with bone and brain windows showed microcranium, skull defects and meningoencephalocele extruding from the enlarged parietal foramina (Fig. 1b,c). The brain CT scan showed corpus callosum agenesis, widened interhemispheric fissure, an occipital paramedian line cyst and cortical dysplasia (Fig. 1d). The characteristic facial phenotype prompted us to sequence the ALX4 related to FND-2 syndrome. Genomic DNA from the proband and his mother was extracted and the entire coding region of the ALX4 was sequenced by Sanger sequencing method (ABI_PRISM 3130 Genetic Analyzer (Applied Biosystems® , Waltham, MA USA)). A homozygous c.205delG mutation in exon 1 (Fig. 1e) was found in the proband, causing a frameshift from codon 69 and leading to a premature termination codon at 112th position (p.Gly69fsX112). The premature stop codon is predicted to cause the removal of 232 amino acids, including the homeodomain encoded by exons 2 and 3, which may have caused the protein total loss-of-function and might be related to the patient’s severe phenotype. The mutation was found in heterozygote state in the mother. CytoScan® HD array (Affymetrix Santa Clara, CA USA), performed both in proband and his mother, revealed large segments of homozygous stretches (total 12.5%), highly suggestive of parental consanguinity (second degree). One of these segments of homozygosity affected a 20.8 Mb region in 11p11.12p14.1 and encompassed the ALX4 gene (Fig. 1f). These data
reinforce an autosomal recessive transmission to FND-2 syndrome. The clinical and molecular findings of the other six patients from literature are summarized in Table 1. Our patient, the first with FND-2 reported in Latin America, displays meningoencephalocele as an additional syndrome feature. The contribution of other factors leading to this additional anomaly could not be excluded, including the possibility of unmasking another recessive mutation due to parental consanguinity. No parietal foramina was detected in the patient’s mother, but she presents with mild craniofacial findings: hypertelorism, broad nasal tip, and diastema (Fig. 1g), similar to the heterozygous patients reported (2, 3). Our Brazilian patient carries a novel homozygous ALX4 mutation showing meningoencephalocele, which can be an additional finding in FND-2 syndrome.
Acknowledgements This work was supported by Fundação de Amparo a Pesquisa do Estado de São Paulo (FAPESP), Brazil. This study was approved by the Research Ethical Committee of Federal University of São Paulo/São Paulo Hospital (CEP 0394/10).
V.A. Melonia M. Moysés-Oliveiraa M.C.C. Melob T.P. Caneloia A.G. Dantasa M.F.F. Soaresc R. Focka P.D. Rodrigues de Nicolaa M.R. Dias-da-Silvab M.I. Melaragnoa a Department of Morphology and Genetics, Genetics Division b Department of Medicine, Division of Endocrinology c Department of Imaging Diagnosis Universidade Federal de São Paulo, São Paulo, Brazil References 1. Mavrogiannis LA, Antonopoulou I, Baxová A et al. Haploinsufficiency of the human homeobox gene ALX4 causes skull ossification defects. Nat Genet 2001: 27: 17–18. 2. Bertola DR, Rodrigues MG, Quaio CRDC, Kim CA, Passos-Bueno MR. Vertical transmission of a frontonasal phenotype caused by a novel ALX4 mutation. Am J Med Genet 2013: 161: 600–604. 3. Altunoglu U, Satkin B, Uyguner ZO, Kayserili H. Mild nasal clefting may be predictive for ALX4 heterozygotes. Am J Med Genet 2014: 164: 2054–2058. 4. Kariminejad A, Bozorgmehr B, Ashrafi MR, Kariminejad MH. Skull defects, alopecia and distinctive facies: a new syndrome? Clin Dysmorphol 2008: 17: 203–205. 5. Kayserili H, Uz E, Niessen C et al. ALX4 dysfunction disrupts craniofacial and epidermal development. Hum Mol Genet 2009: 18: 4357–4366. 6. Alanay Y, Uz E, Eda Utine G, Tuncbilek G, Boduroglu K, Akarsu NA. 22nd –25th October 2012. Disruption of OAR Domain in ALX4 results in Autosomal Recessive Severe Frontonasal Dysplasia with Facial Hypertrichosis. Abstract book: 15th Manchester Dysmorphology Conference, University of Manchester. p.12.
595
Letter to the Editor 7. Kayserili H, Altunoglu U, Ozgur H, Basaran S, Uyguner ZO. Mild nasal malformations and parietal foramina caused by homozygous ALX4 mutations. Am J Med Genet 2012: 158: 236–244. 8. Kariminejad A, Bozorgmehr B, Alizadeh H et al. Skull defects, alopecia, hypertelorism, and notched alae nasi caused by homozygous ALX4 gene mutation. Am J Med Genet 2014: 164: 1322–1327.
Correspondence: Vera Ayres Meloni Department of Morphology and Genetics Universidade Federal de São Paulo
596
Rua Botucatu 740, São Paulo 04023-900 Brazil Tel.: +55 11 5576 4260 fax: +55 11 5576 4260 e-mail: [email protected]
© 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd CLINICAL GENETICS doi: 10.1111/cge.12595
Letter to the Editor
Novel homozygous ALX4 mutation causing frontonasal dysplasia-2 in a patient with meningoencephalocele To the Editor: Mutations in ALX4 gene have been associated with skull ossification defects including symmetrical parietal
foramina (1). While ALX4 heterozygous loss-of-function has been associated with symmetrical parietal ossification defects with vertical transmission (2, 3),
Fig. 1. Frontal facial appearance of the proband at 5 months of age (a). 3-D computerized tomographic (CT) scan of proband at 1 day old showing microcranium, brachycephaly, hypertelorism and meningoencephalocele in the high convexity of the skull extruding from the enlarged parietal foramen (b). 3-D CT scan of proband at 13 months showing bone defects abnormalities on cranial bone plate (c). Brain CT scan of the proband at 13 months showing corpus callosum agenesis, widened interhemispheric fissure and an occipital paramedian line cyst, lateral ventricles poorly characterized and probable cortical dysplasia (d). Partial sequencing electropherogram of the ALX4 gene’s exon 1 using specific intronic primers (list available on request). Control shows the ALX4 normal DNA reference (NG_015809.1) and its respective amino acids below codons; proband shows ALX4 p.Gly69fsX112 (c.205delG) homozygous mutation with the representation of the first eight altered amino acids (underlined) before the stop codon created downstream (X112) caused by a G-deletion frameshift in both alleles; mother showing heterozygous deletion (displayed as reverse sequencing) (e). Genomic array data for chromosome 11p showing a 20.8 Mb region of homozygosity (purple bar) at chr11:30,776,678–51,563,636 (GRCh37/hg19), which encompassed ALX4 gene (f). Frontal facial appearance of the patient’s mother (g).
593
594
793C>T homozygous
Mutation in ALX4 gene Complementary molecular research
− − Kinked CC, hypoplasia of Kinked CC cerebellar vermis
+ Lipoma of CC
793C>T homozygous
673C>G homozygous
Normal Left accessory nipple
− − − − − Preauricular skin tags −
+ Alopecia + + + Large lobules −
MR/DD
− − + + + +
+ + + + + +
(IVS+1755_*1503del2388) homozygous
Borderline normal Facial hypertrichosis
− − − − − − −
− − + − + NE
+ − − +
+ − + +
c.503delC in exon 2 homozygous
Normal
+ Hypoplastic occipital lobe and occipital cleft thin isthmus of kinked CC
− + + + + − −
− − + + + +
+ + + +
−
Absent nasal bone
−
Aplasia of nasal bones, underdevelopment of maxillary bones + + + −
Kariminejad et al. (4, 8) F 8 years Iran CB
Alanay et al. (6) F 9 years Turkey Calvarial defect
M 6, 5 years Turkey Parietal foramina
Kayserili et al. (7)
M 8 years Turkey Calvarial defects, coronal synostosis
Kayserili et al. (5) case 2
+, present; −, absent; CB, cranium bifidum; CC, corpus callosum; DD, developmental delay; F, female; M, male; MR, mental retardation; NE, not evaluated. a Adapted and modified table from Kariminejad et al., (8).
MR/DD
Cognition Other
M 3 years Turkey CB, calvarial defects, ethmoid aplasia, coronal synostosis Facial skeletal defects Aplasia of nasal bones, underdevelopment of maxillary bones Hypertelorism + Telecanthus + Blepharophimosis + Upslanting palpebral − fissures Microphthalmia + Strabismus + Wide nasal bridge + Broad columella + Notched nares + Broad and depressed + nasal tip Broad philtrum + Sparse hair Alopecia Absent eyelashes + Absent eyebrows + Absent body hair + Ears abnormalities Low set, large ears Genitalia Bilateral cryptorchidism abnormalities Microcephaly + Brain abnormalities Lipoma of CC, partial CC agenesis, partial vermian agenesis
Sex Age at examination Country of origin Skull defects
Kayserili et al. (5) case 1
Table 1. Comparison between patients described in literature with ALX4 homozygous mutations and the case reported hereina
Affymetrix CytoScan HD SNP-array arr(1–22)×2,(XY)×1
+ Median parietal meningoencephalocele, CC agenesis, occipital paramedian line cyst, cortical dysplasia and lateral ventricles poorly characterized DD Umbilical hernia, dermatite, floppy infant c.205delG in exon 1 homozygous
+ Alopecia + + + Low set, large ears Bilateral cryptorchidism, hypospadia
− + + + + +
Posterior cleft palate, nasal bone hipoplasia and underdevelopment of maxillary bones + − + −
M 5 months Brazil Calvarian defects, enlarged parietal foramina
Present case
Letter to the Editor
Letter to the Editor homozygous mutations are associated with frontonasal dysplasia spectrum with alopecia and characteristic phenotype (4–8). In 2008, Kariminejad et al. (4) reported a patient with skull defects and alopecia in whom later a homozygous ALX4 mutation (c.503delC) was found (8). A homozygous ALX4 nonsense mutation (c.793C>T) was found in two patients with similar phenotype and intellectual disability, suggesting a novel malformation syndrome named frontonasal dysplasia-2 (FND-2, MIM #613451) (5). Another homozygous missense mutation (c.673C>G) in the ALX4 was described in a patient with mild facial phenotype, parietal foramina and brain malformation, but normal cognition (7). Here, we report on a Brazilian boy with a novel homozygous mutation in the ALX4 (c.207delG) causing FND-2 syndrome and parietal meningoencephalocele. The patient (Fig. 1a–d) is the second child of a young healthy mother and unknown father. He was born at 38 weeks gestation by cesarean section due to prenatal diagnosis of meningoencephalocele, weight 2795 g (−1 SD), length 48 cm (−1 SD), and head circumference (HC) uncharted. At 1 month, surgical resection of the meningoencephalocele was performed. The first genetic evaluation was at 5 months and his measurements were weight 4640 g (−3 SD), length 57.2 cm (−3 SD) and HC 32 cm (−3 SD). He presented with microsomia, microcephaly, total alopecia, hypertelorism, short palpebral fissures, bilateral horizontal nystagmus, depressed nasal bridge, bifid nasal tip, posterior medial palatine fissure, bilateral cryptorchidism, hypospadia, anteriorly placed anus, atopic dermatitis, hypotonia and severe neurodevelopmental delay. The three-dimensional craniofacial computerized tomographic scan (3-D CT) with bone and brain windows showed microcranium, skull defects and meningoencephalocele extruding from the enlarged parietal foramina (Fig. 1b,c). The brain CT scan showed corpus callosum agenesis, widened interhemispheric fissure, an occipital paramedian line cyst and cortical dysplasia (Fig. 1d). The characteristic facial phenotype prompted us to sequence the ALX4 related to FND-2 syndrome. Genomic DNA from the proband and his mother was extracted and the entire coding region of the ALX4 was sequenced by Sanger sequencing method (ABI_PRISM 3130 Genetic Analyzer (Applied Biosystems® , Waltham, MA USA)). A homozygous c.205delG mutation in exon 1 (Fig. 1e) was found in the proband, causing a frameshift from codon 69 and leading to a premature termination codon at 112th position (p.Gly69fsX112). The premature stop codon is predicted to cause the removal of 232 amino acids, including the homeodomain encoded by exons 2 and 3, which may have caused the protein total loss-of-function and might be related to the patient’s severe phenotype. The mutation was found in heterozygote state in the mother. CytoScan® HD array (Affymetrix Santa Clara, CA USA), performed both in proband and his mother, revealed large segments of homozygous stretches (total 12.5%), highly suggestive of parental consanguinity (second degree). One of these segments of homozygosity affected a 20.8 Mb region in 11p11.12p14.1 and encompassed the ALX4 gene (Fig. 1f). These data
reinforce an autosomal recessive transmission to FND-2 syndrome. The clinical and molecular findings of the other six patients from literature are summarized in Table 1. Our patient, the first with FND-2 reported in Latin America, displays meningoencephalocele as an additional syndrome feature. The contribution of other factors leading to this additional anomaly could not be excluded, including the possibility of unmasking another recessive mutation due to parental consanguinity. No parietal foramina was detected in the patient’s mother, but she presents with mild craniofacial findings: hypertelorism, broad nasal tip, and diastema (Fig. 1g), similar to the heterozygous patients reported (2, 3). Our Brazilian patient carries a novel homozygous ALX4 mutation showing meningoencephalocele, which can be an additional finding in FND-2 syndrome.
Acknowledgements This work was supported by Fundação de Amparo a Pesquisa do Estado de São Paulo (FAPESP), Brazil. This study was approved by the Research Ethical Committee of Federal University of São Paulo/São Paulo Hospital (CEP 0394/10).
V.A. Melonia M. Moysés-Oliveiraa M.C.C. Melob T.P. Caneloia A.G. Dantasa M.F.F. Soaresc R. Focka P.D. Rodrigues de Nicolaa M.R. Dias-da-Silvab M.I. Melaragnoa a Department of Morphology and Genetics, Genetics Division b Department of Medicine, Division of Endocrinology c Department of Imaging Diagnosis Universidade Federal de São Paulo, São Paulo, Brazil References 1. Mavrogiannis LA, Antonopoulou I, Baxová A et al. Haploinsufficiency of the human homeobox gene ALX4 causes skull ossification defects. Nat Genet 2001: 27: 17–18. 2. Bertola DR, Rodrigues MG, Quaio CRDC, Kim CA, Passos-Bueno MR. Vertical transmission of a frontonasal phenotype caused by a novel ALX4 mutation. Am J Med Genet 2013: 161: 600–604. 3. Altunoglu U, Satkin B, Uyguner ZO, Kayserili H. Mild nasal clefting may be predictive for ALX4 heterozygotes. Am J Med Genet 2014: 164: 2054–2058. 4. Kariminejad A, Bozorgmehr B, Ashrafi MR, Kariminejad MH. Skull defects, alopecia and distinctive facies: a new syndrome? Clin Dysmorphol 2008: 17: 203–205. 5. Kayserili H, Uz E, Niessen C et al. ALX4 dysfunction disrupts craniofacial and epidermal development. Hum Mol Genet 2009: 18: 4357–4366. 6. Alanay Y, Uz E, Eda Utine G, Tuncbilek G, Boduroglu K, Akarsu NA. 22nd –25th October 2012. Disruption of OAR Domain in ALX4 results in Autosomal Recessive Severe Frontonasal Dysplasia with Facial Hypertrichosis. Abstract book: 15th Manchester Dysmorphology Conference, University of Manchester. p.12.
595
Letter to the Editor 7. Kayserili H, Altunoglu U, Ozgur H, Basaran S, Uyguner ZO. Mild nasal malformations and parietal foramina caused by homozygous ALX4 mutations. Am J Med Genet 2012: 158: 236–244. 8. Kariminejad A, Bozorgmehr B, Alizadeh H et al. Skull defects, alopecia, hypertelorism, and notched alae nasi caused by homozygous ALX4 gene mutation. Am J Med Genet 2014: 164: 1322–1327.
Correspondence: Vera Ayres Meloni Department of Morphology and Genetics Universidade Federal de São Paulo
596
Rua Botucatu 740, São Paulo 04023-900 Brazil Tel.: +55 11 5576 4260 fax: +55 11 5576 4260 e-mail: [email protected]
