Genetic testing and prenatal diagnosis for a Chinese pedigree affected with Waardenburg syndrome type 4C due to heterozygous deletion of SOX10 gene / 中华医学遗传学杂志

OBJECTIVE@#To explore the genetic basis for a Chinese pedigree featuring congenital profound syndromic deafness and chronic constipation, and provide prenatal diagnosis for a high-risk fetus.@*METHODS@#Whole-exome sequencing was carried out to analyze the sequences of genes associated with hereditary deafness, and multiplex ligation-dependent probe amplification (MLPA) was used to verify the candidate variant in the proband's parents and the fetus.@*RESULTS@#The proband was found to have harbored a heterozygous deletion of SOX10, a pathogenic gene associated with Waardenburg syndrome type 4C (WS4C). The same deletion was found in her mother (with profound syndromic deafness and chronic constipation) and the fetus, but not in her father with normal hearing. Based on the guidelines from the American College of Medical Genetics and Genomics (ACMG) and Association for Molecular Pathology (AMP), the SOX10 gene deletion was predicted to be a pathogenic variant (PVS1+PM2_Supporting+PP1+PP4).@*CONCLUSION@#The pedigree was diagnosed with WS4C, which has conformed to an autosomal dominant inheritance. Deletion of the entire SOX10 gene, as a loss-of-function variant, probably underlay its pathogenesis. Above finding has facilitated genetic counseling and prenatal diagnosis for this family.

Analysis of genetic characteristics in two Chinese children of type Ⅱ Waardenburg syndrome / 中华耳鼻咽喉头颈外科杂志

Objective: To screen and analyze the mutations of MITF gene in two children of type Ⅱ Waardenburg syndrome (WS2) from different families in Yunnan,China,and to explore the possible molecular pathogenesis. Methods: With informed consent, medical history collection, physical examinations, audiological evaluation, and high resolution computer tomography (HRCT) scan of temporal bone were performed on the two WS2 probands and their family members. Genomic DNA was extracted from peripheral blood of all individuals. The coding regions including all exons, part of introns and promoters of MITF, PAX3, SOX10, SNAI2, END3, ENDRB, and KITLG genes were sequenced by high-throughput sequencing. According to the results of high-throughput sequencing, pathogenic mutations detected in the probands and their parents were verified by Sanger sequencing. Results: The proband 1 carried c.641_643delGAA mutation in the 7th exon of MITF gene, which was a frame-shift mutation resulting in an amino acid change of p.214delR. It was a de novo mutation as the parents of proband 1 showed no variation on this site. The proband 2 carried heterozygous loss of the large fragment ranging from exon 1 to exon 9 of MITF gene, which defected the function of MITF protein. Conclusion: Genetic examinations provide important evidence for diagnosis of Waardenburg syndrome. Heterozygous mutation c.641_643delGAA and heterozygous loss of the large fragment ranging from exon 1 to exon 9 of MITF gene might be the molecular pathogenesis of the two WS2 probands in this study.

Síndrome Waardenburg. Presentación de una familia afectada / Syndrome Waardenburg. Presentation of an affected family

Fundamento: El síndrome de Waardenburg es una enfermedad genética caracterizada por anomalías de la pigmentación y sordera neurosensorial. Se describen varios tipos clínicos, con gran heterogeneidad genética, la mayoría de los casos publicados presentan un patrón de herencia autosómico dominante, aunque se describen otras formas de herencia. Objetivo: Mostrar una familia con varios miembros afectados representativa de expresividad variable. Presentación de caso: Se presenta una familia con siete enfermos donde predomina la hipoacusia de grado variable al igual que las alteraciones de la pigmentación de la piel, el pelo y el iris. El adecuado diagnóstico y asesoramiento genético, unido a la oportuna intervención con el implante coclear ha permitido la incorporación adecuada en la enseñanza normal a estos enfermos. Conclusiones: Es importante el diagnóstico oportuno para realizar acciones con la finalidad de mejorar la calidad de vida y la correcta incorporación social de estos pacientes.

Background: The syndrome of Waardenburg is a genetic illness characterized by anomalies of the pigmentation and neurosensory deafness. Several clinical types are described, with great genetic heterogeneity; most of the published cases present a pattern of autos’omico dominant inheritance, although other inheritance forms are described Objective: To show a representative family with several affected members of variable expression. Case presentation: A family is presented with seven sick persons where the hypo acoustic of variable grade prevail the same as the alterations of the pigmentation of the skin, the hair and the iris. The appropriate diagnose and genetic advice, together to the opportune intervention with the cochlear implants has allowed the adapted incorporation in the normal teaching to these sick persons Conclusions: It is important the opportune diagnosis to carry out actions with the purpose of improving the quality of life and the correct social incorporation of these patients.

Síndrome de Waardenburg: aspectos oftalmológicos e critérios de diagnóstico: relatos de casos / Waardenburg syndrome: ophthalmic findings and criteria for diagnosis: case reports

OBJETIVO: Descrever as características clínicas e imaginológicas de duas famílias com a síndrome de Waardenburg, sendo uma do tipo I e outra do tipo II, enfatizando as manifestações oftalmológicas, bem como o padrão de herança genética. MÉTODO: Realizou-se um estudo clínico envolvendo as duas famílias afetadas pela síndrome de Waardenburg, sendo, através dos heredogramas, determinado o padrão de herança genética presente. Também foram realizadas análises oftalmológicas abordando a medida da acuidade visual, a presença de distopia cantorum (telecanto), a avaliação da coloração da íris e o mapeamento de retina, além de exames otológicos e dermatológicos. RESULTADOS: O heredograma da família afetada pela síndrome de Waardenburg tipo I revelou um modo autossômico dominante de transmissão. A condição estava presente em 85,71% dos pacientes. A distopia cantorum foi a alteração mais frequente, seguida pela mecha branca na pele da fronte, hipopigmentação da íris e da retina e surdez neurossensorial. A família com síndrome de Waardenburg tipo II apresentou 33,33% dos familiares com a alteração. Nenhum membro apresentou distopia cantorum e hipopigmentação de íris. Três pacientes apresentaram surdez neurossensorial (12,5%), associada ao topete branco e manchas acrômicas confluentes pelo corpo. CONCLUSÃO: O presente estudo mostra a importância do oftalmologista no auxílio do diagnóstico desta rara condição genética, uma vez que inclui alterações oftalmológicas como telecanto, hipopigmentação da íris e retina. A distopia cantorum é o principal critério diagnóstico para diferenciar o tipo I do II e deve ser feita por oftalmologista treinado. As famílias encontram-se em acompanhamento multiprofissional, tendo recebido orientações genéticas e os cuidados referentes à proteção ocular.

PURPOSE: To describe the clinical and imaginological features of two families with Waardenburg syndrome: type I and II, with emphasis on ophthalmic manifestations, as well as the pattern of genetic inheritance. METHODS: We conducted a clinical study involving two families affected by Waardenburg syndrome, and through the pedigree, determined the present pattern of genetic inheritance. Analyses were performed including the measurement of visual acuity, the presence of dystopia cantorum (telecanthus), evaluation of iris color and retinal mapping, as well as dermatological and otological examinations. RESULTS: The pedigree of the family affected by the Waardenburg syndrome type I showed an autosomal dominant mode of transmission. The syndrome was present at 85.71% of patients. The dystopia cantorum was the most frequent feature, followed by the white streak on the skin of the forehead, hypopigmentation of the iris and retina and deafness. The Waardenburg syndrome family type II had 33.33% of family members affected by the syndrome. No member had dystopia cantorum and hypopigmentation of the iris. Three patients had sensorineural hearing loss (12.5%), associated with white forelock and achromatic spots confluent by the body. CONCLUSION: This study shows the importance of the ophthalmologist in aiding the diagnosis of this rare genetic condition, since it includes ocular disorders such as telecanthus, hypopigmentation of the iris and retina. The cantorum dystopia is the main diagnostic criterion to differentiate type I and II syndrome and should be done by a trained ophthalmologist. The families are in medical monitoring, receiving genetic guidelines and care related to eye protection.

Three Cases of Waardenburg Syndrome Type 2 in a Korean Family

Waardenburg syndrome (WS) is a rare, autosomal dominant disorder characterized by sensorineural hearing loss, pigmentary disturbances of the skin, hair, and iris, and other developmental defects such as lateral displacement of both medial canthi and lacrimal puncta called dystopia canthorum. While mutations of the PAX3 (paired box) gene have been identified in about 99% of WS type 1 cases, WS type 2 is a heterogeneous group, with about 15% of cases caused by mutations in microphthalmia associated transcription factor (MITF). We have experienced three cases of typical WS type 2 in a Korean family, for whom full ocular examination and genetic studies were performed. The genetic studies revealed no mutation in either PAX3 or MITF genes. The genetic basis, as yet unknown for most cases of WS type 2, might be found with further investigation.

Síndrome de Waardenburg: presentación de un caso y revisión de los diferentes tipos / Waardenburg syndrome type I: a case presentation

Introducción. En 1951 Waardenburg describió un nuevo padecimiento de etiología hereditaria, con características clínicas específicas; a partir de entonces, se han publicado más de 1,500 pacientes similares. Caso clínico. Paciente masculino de 14 años de edad, hijo de padres consanguíneos (primos en primer grado), con antecedentes de retardo en el desarrollo psicomotor. A la exploración física se le encontró: talla de 1.58 m, peso de 81.5 kg; con telecanto, heterocromía de iris, sordera neurosensorial y alteraciones en la pigmentación del pelo, pestañas y cejas. Estudio citogenético: cariotipo en linfocitos de sangre periférica y con técnica de bandas G, sin obtenerse evidencias de alteraciones cromosómicas ni estructurales. Conclusión. A pesar de la existencia de consanguinidad de primer grado en la familiar, la herencia corresponde al tipo I del padecimiento. Además, es necesario realizar como complemento al estudio clínico los marcadores genéticos específicos en todos los casos para identificar la variedad y proceder al asesoramiento genético

Confluencia de sordera no sindromica autosomica recesiva y sindrome de Waardenburg en al isla de Providencia-Colombia / Non-sindromatic reseciv autosomic. Deafness and Waardenburg in Providence Island-Colombia

Los estudios genéticos en la isla de Providencia, Colombia, se originaron ante el conocimiento de una alta frecuencia de sordera. La característica principal del grupo es la de una población de raza negra en su mayoría, con alto grado de consanguinidad, que presenta sordera neurosensorial bilateral profunda, asociada con síndrome de Waardenburg (WS) en algunas personas. Este síndrome se caracteriza por anormalidades en la pigmentación en la piel, los ojos y el cabello, asociado en algunos individuos (pero no todos) con sordera neurosensorial. En la historia de la isla de Providencia -Colombia- han existido más de 34 sordos. En el momento residen 21 individuos sordos, de los cuales tuvimos la oportunidad de examinar a 17. Actualmente la población de "nativos" isleños es de 3,400 individuos, y dado que 21 de ellos son sordos, la frecuencia de sordera sería de aproximadamente 6.2 en 1,000 habitantes nativos; frecuencia considerablemente mayor a la de la población general que es de 1 en 1,000. Del total de 17 sordos estudiados encontramos que el 47 por ciento (8/17) presenta sordera no-sindrómica autosómica recesiva, el 29 por ciento (5/ 17) presenta síndrome de Waardenburg (ws) y el 24 por ciento restante (4/17) corresponde a sorderas aisladas o casos únicos. Existen además, cuatro individuos que la población considera como sordos pero nosotros no tuvimos la oportunidad de examinarlos. Tenemos entonces una población muy interesante, en la que se ha demostrado que todas las familias afectadas están relacionadas entre sí, dada la alta endogamia propia de esta población isleña, en donde hay ancestros comunes para la gran mayoría de los apellidos nativos. Lo más llamativo es la confluencia en la misma población, de individuos que presentan sordera únicamente e individuos con sordera asociada al síndrome de Waardenburg. Esto crea una condición única y extremadamente valiosa para los estudios de estas enfermedades en donde se pretende definir si todos los casos de sordera en la isla tienen una misma etiología genética, o si son dos enfermedades genéticas diferentes. Es decir, definir si el gen causante de la sordera no-sindrómica es el mismo gen causante de la sordera observada en el síndrome de Waardenburg

Síndrome de Waardenburg: estudo de uma família / Waardenburg syndrome: study of a family

A síndrome de Waardenbura, descrita em 1951, é uma condiçäo autossômica e dominante que apresenta penetrância e expressividade variáveis de seus caracteres, e é representada por: deslocamento lateral dos cantos internos dos olhos (dystopia canthorum), hiperplasia da porçäo medial dos supercílios, base nasal proeminente e alargada, heterocromia ou hipoisocromia de íris, surdez congênita neurossensorial uni ou bilateral, mecha branca frontal ou encanecimento precoce, e hipopigmentaçäo cutânea. Este estudo foi realizado a propósito de uma família em que a mäe e três dos seus quatro filhos apresentam quadro clínico típico da síndrome de Waardenbura,. Foram feitas avaliaçöes dermatológica, oftalmológica, otorrinolaringológica e odontológica, estudo dos cariótipos, determinaçäo do HLA e análise estrutural dos melanócitos da pele hipopigmentada e normal à microscopia eletrônica