Genetic counseling for a three-generation Chinese family with Waardenburg syndrome type II associated with a rare SOX10 mutation

Abstract

Objective: Waardenburg syndrome is clinically and genetically heterogeneous. The SOX10 mutation related with Waardenburg syndrome type II is rare in Chinese. This study aimed to uncover the genetic causes of Waardenburg syndrome type II in a three-generation family to improve genetic counseling.

Methods: Complete clinical and molecular evaluations were conducted in a three-generation Han Chinese family with Waardenburg syndrome type II. Targeted genetic counseling was provided to this family.

Results: We identified a rare heterozygous dominant mutation c.621C>A (p.Y207X) in SOX10 gene in this family. The premature termination codon occurs in exon 4, 27 residues downstream of the carboxyl end of the high mobility group box. Bioinformatics prediction suggested this variant to be disease-causing, probably due to nonsense-mediated mRNA decay. Useful genetic counseling was given to the family for prenatal guidance.

Conclusion: Identification of a rare dominant heterozygous SOX10 mutation c.621C>A in this family provided an efficient way to understand the causes of Waardenburg syndrome type II and improved genetic counseling.

Keywords: Genetic counseling; Hearing impairment; Nonsense-mediated mRNA decay; SOX10 mutation; Waardenburg syndrome.