De novo dominant mutation of SOX10 gene in a Chinese family with Waardenburg syndrome type II

Objective: Waardenburg syndrome is a rare genetic disorder, inherited as an autosomal dominant trait. The condition is characterized by sensorineural hearing loss and pigment disturbances of the hair, skin, and iris. The de novo mutation in the SOX10 gene, responsible for Waardenburg syndrome type II, is rarely seen. The present study aimed to identify the genetic causes of Waardenburg syndrome type II in a Chinese family.

Methods: Clinical and molecular evaluations were conducted in a Chinese family with Waardenburg syndrome type II.

Results: A novel SOX10 heterozygous c.259-260delCT mutation was identified. Heterozygosity was not observed in the parents and sister of the proband, indicating that the mutation has arisen de novo. The novel frameshift mutation, located in exon 3 of the SOX10 gene, disrupted normal amino acid coding from Leu87, leading to premature termination at nucleotide 396 (TGA). The high mobility group domain of SOX10 was inferred to be partially impaired.

Conclusion: The novel heterozygous c.259-260delCT mutation in the SOX10 gene was considered to be the cause of Waardenburg syndrome in the proband. The clinical and genetic characterization of this family would help elucidate the genetic heterogeneity of SOX10 in Waardenburg syndrome type II. Moreover, the de novo pattern expanded the mutation data of SOX10.