Clinical phenotype in an Usher syndrome family with compound heterozygous mutations of CDH23

Objective To study the phenotypic characteristics and clinical classification of Usher syndrome (USH) in a Chinese family, and screen the disease-causing mutation(s). Methods A family of 3 generations with 9 members (2 patients, 7 healthy members) was included in this study. A pedigree figure was drawn after the history was recorded in detail. Ophthalmologic examinations were performed in all the members except Ⅲ2, who was too young to be examined, including BCVA, IOP, biomicroscopy of the anterior eye segment, color photo of fundus, OCT and ERG. In addition, audiometric tests and vestibular function tests, including pure tone audiometry, tympanometry, acoustic reflex, cold and hot reaction, eye movement and nystagmus were performed. Then the clinical data were analyzed to determine the clinical classification of USH and to screen the suspected mutation (s). Results Usher syndrome type Ⅰ was found in two patients (Ⅱ1, Ⅱ4) based on clinical features. The other members in USH family did not show the characteristics of this disease. USH was autosomal recessive inherited in this family and two novel compound heterozygous mutations (c.6253G> A and c.287_288insG) of CDH23 were identified. Conclusion In this study, we have confirmed the clinical classification by studying the phenotypic characteristics of USH family, and indentified pathogenic gene mutations of USH.