Analysis in mutation in MITF gene in type Ⅱ Waardenburg syndrome

  Objective   To explore the genetic factors of a hereditary disease named Waardenburg syndrome (WS) in one case so as to achieve the goal of its prevention by genetic counseling.

  Methods   Five family members (Han nationality) of three generations were included in the study. Peripheral venous blood samples were collected and DNA was extracted after a detailed medical history inquiry. Mutation screening of all exons for three common deaf genes and six WS candidate genes was performed by Sanger sequencing.

  Results   The c.C763T (p.R255X) in MITF truncated mutation segregated with the phenotypes within the family.

  Conclusion   The truncated mutated p.R255X results in the mutation of the 255th arginine codon into termination codon, leading to premature termination of protein synthesis, which is probably the hereditary pathogenic factor of this family. The lack of haploid dose caused by the normal function loss of MITF protein is likely to be the pathogenic mechanism of this mutation. Genetic counseling, marital guidance and prenatal diagnostic techniques can prevent deafness in offspring caused by the mutation.