Genetic testing and genotype-phenotype analysis for a child with X-linked hypohidrotic ectodermal dysplasia / 中华医学遗传学杂志

OBJECTIVE@#To carry out genetic testing for a Chinese patient with X-linked hypohidrotic ectodermal dysplasia (XLHED) and explore its genotype-phenotype correlation.@*METHODS@#Clinical data of the patient was collected. Peripheral blood samples were taken from the patient, his parents and 100 unrelated healthy controls. Genetic variants were detected by using next-generation sequencing using a skin-disease panel through targeted capture and next generation sequencing. Candidate variant was verified by Sanger sequencing. All literature related to genetic testing of XLHED patients in China was searched in the database, and the genotypes and phenotypes of patients in the literature and the correlation between them were statistically analyzed.@*RESULTS@#A novel splice site variant c.655_689del was detected in the patient but not among his parents and the 100 unrelated healthy controls. So far 61 variants of the EDA gene have been identified among Chinese patients with XLHED, which suggested certain degree of genotype-phenotype correlation.@*CONCLUSION@#A novel c.655_689del variant has been identified in the EDA gene, which has expanded the spectrum of EDA gene variant and facilitated delineation of the genotype-phenotype correlation of XLHED.

Clinical and genetic analysis of a child with X-linked hypohidrotic ectodermal dysplasia / 中华医学遗传学杂志

OBJECTIVE@#To explore the clinical and genetic characteristics of a child with X-linked hypohidrotic ectodermal dysplasia (XLHED).@*METHODS@#Clinical data of the child was collected. Peripheral blood samples were taken from the child and his parents with informed consent and subjected to copy number variation (CNV) analysis and whole exome sequencing (WES).@*RESULTS@#The male infant manifested sparse hair, anhidrosis, anuresis due to polycystic kidney dysplasia, external genital malformation and anal atresia. WES has revealed a 406 bp hemizygous deletion at Xq13 (68 836 147-68 836 553) in the proband, which encompassed exon 1 of the EDA gene. A heterozygous deletion at the same site was detected in the mother, while no deletion or duplication of the site was detected in the father.@*CONCLUSION@#The hemizygous deletion of EDA gene exon 1 probably underlay the ectodermal dysplasia in the proband. Above result has provided a basis for genetic counseling and prenatal diagnosis for the family.

Phenotypic and genetic analysis of a case with hypohidrotic ectodermal dysplasia due to Xq13.1 microdeletion / 中华医学遗传学杂志

OBJECTIVE@#To investigate the clinical phenotype and genetic characteristics of a patient with hypohidrotic ectodermal dysplasia (HED) due to partial deletion of EDA gene.@*METHODS@#The child has presented with HED complicated with epilepsy. Family trio whole exome sequencing (Trio-WES), copy number variation sequencing (CNV-seq), and karyotype analysis were carried out to explore the underlying genetic etiology.@*RESULTS@#The proband, a 7-year-and-8-month-old boy, presented with thin curly hair, thin and sparse eyebrow, xerosis cutis, susceptibility to hyperthermia from childhood, hypohidrosis, sharp/sparse/absent teeth, saddle nose, prominent forehead, auricle adulation and seizure. He was found to have a normal chromosomal karyotype, and no abnormality was found by Trio-WES. Genome-wide CNV-seq revealed a 341.90 kb deletion at Xq13.1q13.1 (chrX: 68 796 566-69 138 468). As verified by PCR-electrophoresis, the deletion has removed part of the EDA gene. The deletion was derived from his mother with normal hair, mild xerosis cutis, and sparse, decidulated and nail-like teeth. The mother was detected with a heterozygous 242.10 kb deletion at Xq13.1q13.1 (chrX: 68 836 154-69 078 250).@*CONCLUSION@#Both the proband and his mother have carried a Xq13.1 microdeletion involving part of the EDA gene. The clinical phenotypes of the mother and the proband were consistent with the clinical characteristics of X-linked recessive HED, for which partial deletion of the EDA gene is probably accountable.

Displasia ectodérmica hipohidrótica ligada al cromosoma X de novo por variante recurrente en un paciente mexicano / X-linked hypohidrotic ectodermal dysplasia by a de novo recurrent variant in a Mexican patient

Resumen Introducción: Las displasias ectodérmicas son un grupo de genodermatosis que se caracterizan por distrofia de las estructuras derivadas del ectodermo. De ellas, la variedad más común es la hipohidrótica, con una incidencia de 7/100,000 nacidos vivos observada en todos los grupos étnicos. La displasia ectodérmica hipohidrótica tiene distintas etiologías. La presentación más frecuente es la asociada a un patrón de herencia ligado al cromosoma X, causada por variantes patogénicas del gen EDA en Xq13.1. EDA codifica a la ectodisplasina A, una molécula de señalización que participa en la comunicación epitelio-mesénquima durante el desarrollo de la piel y los anexos. Caso clínico: Varón de 6 años con las características clínicas cardinales de la displasia ectodérmica hipohidrótica ligada al cromosoma X (DEHLX), que incluyen hipotricosis, oligodoncia e hipohidrosis. El análisis del gen EDA por secuenciación directa mostró la presencia de la variante patogénica c.466C>T, p.Arg156Cys, rs132630313 con presentación de novo en el paciente. Esta variante ya ha sido reportada en diferentes poblaciones, incluyendo familias mexicanas, y constituye un punto caliente para mutación en EDA. Se analizaron los hallazgos clínicos, la etiología y el manejo de la DEHLX, en la que de manera reciente se ha planteado la posibilidad de otorgar tratamiento prenatal para prevenir sus manifestaciones clínicas. Conclusiones: Se pone de relevancia que el análisis molecular en pacientes con DEHLX corrobora el diagnóstico clínico y permite brindar asesoramiento genético con bases moleculares.

Abstract Background: Ectodermal dysplasias are a group of genodermatoses characterized by dystrophy of ectodermal derived structures. The most frequent presentation of the ectodermal dysplasias is the hypohidrotic type, which has an incidence of 7/100,000 newborns and has been described in all ethnic groups. The hypohidrotic ectodermal dysplasia (HED) has different etiologies, and it is more frequently associated with an X-linked pattern of inheritance caused by pathogenic variants of the EDA gene in Xq13.1. EDA encodes the protein ectodisplasin A, a signal molecule which participates in epithelium and mesenchymal development of the skin. Case report: A 6 year-old male patient with the main clinical characteristics of the X-linked HED including hypotrichosis, hypodontia and hypohidrosis. The direct sequencing analysis of EDA in our patient detected a de novo pathogenic variant, c.466C>T, p.Arg156Cys, rs132630313. This variant has been previously described in different ethnic groups, including Mexican families, and is considered a mutational hotspot. The clinical characteristics, etiology and management of the X-linked HED, including the possibility of prenatal therapy in order to avoid the clinical manifestations are discussed. Conclusions: The molecular analysis in patients with X-linked HED is of relevance, as it enables to confirm the clinical diagnosis and also, it allows a genetic assessment with molecular bases.

Detection of EDA gene mutation and phenotypic analysis in patients with hypohidrotic ectodermal dysplasia / 北京大学学报(医学版)

OBJECTIVE@#To detect the ectodysplasin A (EDA) gene mutation in patients with hypohidro-tic ectodermal dysplasia (HED), and to analyze the distribution pattern of missing permanent teeth and the systemic manifestation of HED patients with EDA gene mutation.@*METHODS@#Twelve HED families were enrolled from clinic for genetic history collection, systemic physical examination and oral examination. Peripheral blood or saliva samples were collected from the probands and the family members to extract genomic DNA. PCR amplification and Sanger sequencing were utilized to detect the EDA gene variations, which were compared with the normal sequence (NM_001399.5). The functional impact of EDA gene variants was then evaluated by functional prediction of mutation, conservation analysis and protein structure prediction. The pathogenicity of each EDA gene variation was assessed according to the stan-dards and guidelines of the American College of Medical Genetics and Genomics (ACMG). The systemic phenotype and missing permanent tooth sites of HED patients with EDA gene mutations were summarized, and the missing rate of each tooth position was analyzed and compared.@*RESULTS@#Eight out of twelve HED families were identified to carry EDA gene mutations, including: c.164T>C(p.Leu55Pro); c.457C>T (p.Arg153Cys); c.466C>T(p.Arg156Cys); c. 584G>A(p.Gly195Glu); c.619delG(p.Gly207Profs*73); c.673C>T(p.Pro225Ser); c.676C>T(p.Gln226*) and c.905T>G(p.Phe302Cys). Among them, c.164T>C(p.Leu55Pro); c.619delG(p.Gly207Profs*73); c.673C>T(p.Pro225Ser); c.676C>T(p.Gln226*) and c.905T>G(p.Phe302Cys) were novel mutations. The HED patients with EDA gene mutations in this study were all male. Our results showed that the average number of missing permanent teeth was 13.86±4.49, the average number of missing permanent teeth in the upper jaw was 13.14±5.76, the missing rate was 73.02%. And in the lower jaw, the average number of missing permanent teeth was 14.57±3.05, the missing rate was 80.95%. There was no significant difference in the number of missing teeth between the left and right sides of the permanent dentition (P>0.05). Specifi-cally, the maxillary lateral incisors, the maxillary second premolars and the mandibular lateral incisors were more likely to be missing, while the maxillary central incisors, the maxillary and mandibular first molars had higher possibility of persistence.@*CONCLUSION@#This study detected novel EDA gene pathogenic variants and summarized the distribution pattern of missing permanent teeth of HED patients, thus enriched the variation and phenotype spectrum of EDA gene, and provided new clinical evidence for genetic diagnosis and prenatal consultation.

Prenatal diagnosis of a fetus with X-linked hypohidrotic ectodermal dysplasia / 中华医学遗传学杂志

OBJECTIVE@#To detect variant of EDA gene in a fetus with absence of germ teeth detected by prenatal ultrasonography.@*METHODS@#Clinical data and amniotic fluid and peripheral venous blood samples of the pregnant woman were collected for the analysis. Following extraction of genome DNA, the coding regions of the EDA gene were amplified by PCR and subjected to next-generation sequencing. Candidate variant was verified by Sanger sequencing.@*RESULTS@#The pregnant woman was found to carry a heterozygous c.574G>A variant in the EDA gene, for which the fetus was hemizygous. Bioinformatic analysis suggested the variant to be pathogenic.@*CONCLUSION@#Combined ultrasonographic and genetic findings suggested the fetus is affected with X-linked hypohidrotic ectodermal dysplasia due to pathogenic variant of the EDA gene.

Genetic analysis of a case with ectodermal dysplasia using whole exome sequencing / 中华医学遗传学杂志

OBJECTIVE@#To explore the genetic cause of a patient suspected for congenital ectodermal dysplasia with repeated hyperthermia and to assess the reproductive risk for his family.@*METHODS@#Medical whole-exome sequencing (WES) were used to detect single-nucleotide variations and low-coverage massively parallel copy number variation sequencing (CNV-seq) were employed to verify suspected CNVs. PCR and real-time quantitative PCR were applied to confirm the deletion of EDA gene.@*RESULTS@#The results of WES suggested that the patient carried a hemizygous deletion for chrX:69 243 016-69 395 730. CNV-seq indicated that the patient carried a deletion of approximately 0.12 Mb on Xq13.1, which encompassed the EDA gene. The PCR results confirmed that there was a hemizygous deletion of exons 3 to 8 of the EDA gene. The same deletion was not found in his mother.@*CONCLUSION@#The congenital ectodermal dysplasia of the patient may be attributed to deletion of exons 3 to 8 of the EDA gene, which could be de novo or derive from germline mosaicism of his mother. The WES and CNV-seq are of great value for the diagnosis of rare diseases.

Estudio clínico y molecular en un escolar con displasia ectodérmica hipohidrótica ligada al X / Clinical and molecular study in a child with X-linked hypohidrotic ectodermal dysplasia

Las displasias ectodérmicas comprenden más de 200 entidades clínicamente distintivas, las cuales afectan, al menos, dos estructuras derivadas del ectodermo, que incluyen la piel, el pelo, las unas, los dientes, las glándulas sudoríparas y sebáceas. La displasia ectodérmica hipohidrótica ligada al X es el tipo más frecuente y es causada por mutación del gen EDA, que codifica la ectodisplasina-A. Su frecuencia es menor de 1 en 100000 individuos y se caracteriza clínicamente por presentar hipodoncia, hipohidrosis, hipotricosis y alteraciones oculares. Se expone el caso de un escolar evaluado de forma multidisciplinaria con diagnóstico clínico y molecular de displasia ectodérmica hipohidrótica ligada al X con mutación tipo cambio de sentido c.1133C>,T, p.T378M, en el gen EDA.

Ectodermal dysplasia encompasses more than 200 clinically distinct entities, which affect at least two structures derived from the ectoderm, including the skin, hair, nails, teeth, sweat glands, and sebaceous glands. X-linked hypohidrotic ectodermal dysplasia is the most common type and is caused by mutation of the EDA gene that encodes Ectodysplasin-A. It occurs in less than 1 in 100 000 individuals and is clinically characterized by hypodontia, hypohidrosis, hypotrichosis, and eye dis orders. We present a child evaluated in a multidisciplinary manner with clinical and molecular diagnosis of X-linked hypohidrotic ectodermal dysplasia with type missense mutation c.1133C> T; p.T378M in EDA gene.

PAX9 polymorphism and susceptibility to sporadic non-syndromic severe anodontia: a case-control study in southwest China

Our research aimed to look into the clinical traits and genetic mutations in sporadic non-syndromic anodontia and to gain insight into the role of mutations of PAX9, MSX1, AXIN2 and EDA in anodontia phenotypes, especially for the PAX9. Material and Methods The female proband and her family members from the ethnic Han families underwent complete oral examinations and received a retrospective review. Venous blood samples were obtained to screen variants in the PAX9, MSX1, AXIN2, and EDA genes. A case-control study was performed on 50 subjects with sporadic tooth agenesis (cases) and 100 healthy controls, which genotyped a PAX9 gene polymorphism (rs4904210). Results Intra-oral and panoramic radiographs revealed that the female proband had anodontia denoted by the complete absence of teeth in both the primary and secondary dentitions, while all her family members maintained normal dentitions. Detected in the female proband were variants of the PAX9 and AXIN2 including A240P (rs4904210) of the PAX9, c.148C>T (rs2240308), c.1365A>G (rs9915936) and c.1386C>T (rs1133683) of the AXIN2. The same variants were present in her unaffected younger brother. The PAX9 variations were in a different state in her parents. Mutations in the MSX1 and EDA genes were not identified. No significant diferences were found in the allele and genotype frequencies of the PAX9 polymorphism between the controls and the subjects with sporadic tooth agenesis. Conclusions These results suggest that the association of A240P with sporadic tooth agenesis still remains obscure, especially for different populations. The genotype/phenotype correlation in congenital anodontia should be verified. .

Mutación en el gen EDA1, Ala349Thr en paciente con displasia ectodérmica hipohidrótica ligada a X / Mutation in the ED1, Ala349Thr in a patient with X-linked hypohidrotic ectodermal dysplasia

Hypohidrotic ectodermal dysplasia (HED) is a very rare disease characterized by the absence of eccrine glands, dry skin, scanty hair, and dental abnormalities. It is caused by mutations within the ED1 gene, which encodes a protein, ectodysplasin-A (EDA). Clinical characteristic are frontal bossing, saddle nose, pointed chin, a prominent supraorbital ridge with periorbital hyperpigmenta-tion, and anodontia. Those affected show great intolerance to heat. We report the first Mexican 2-year-old boy with an Ala349Thr missense mutation from Tamaulipas, México.