PAX3 mutations and clinical characteristics in Chinese patients with Waardenburg syndrome type 1

Purpose: To detect paired box gene 3 (PAX3) mutations and associated phenotypes in Chinese patients with Waardenburg syndrome type 1 (WS1). Methods: Five unrelated families with suspected WS1 were selected from our Genomic DNA Repository for Hereditary Eye Diseases. The coding and adjacent intronic regions of PAX3 were amplified by polymerase chain reaction and the amplicons were then analyzed by cycle sequencing. Variations detected were further evaluated in available family members as well as one hundred controls with heteroduplex-single strand conformational polymorphism (heteroduplex-SSCP) analysis and/or clone sequencing. Results: Three novel and two known mutations in PAX3 were detected in five patients, respectively: c. 567_586+17del (p.Asp189_Gln505delinsGluGlyGlyAlaLeuAlaGly), c.456_459dupTTCC (p.Ile154PhefsX162), c.795_800delCTGGTT (p.Trp266_Phe267del), c.799T>A (p.Phe267Ile), and c.667C>T (p.Arg223X). Two novel mutations proved to be de novo as their parents did not carry the mutations. All five patients with PAX3 mutations had dystopia canthorum and different iris color and fundi between their two eyes. However, none had white forelock, skin hypopigmentation, and deafness. Conclusions: Our findings expand the frequency and spectrum of PAX3 mutations and ethnic-related phenotypes in Chinese patients with WS1. De novo mutations in PAX3 have not been reported before.