Usher综合征Ⅱ型患儿临床表型及USH2A基因突变分析OACSTPCD

Objective To investigate the phenotypes and USH2A gene mutation in children with Usher syndrome type Ⅱ.Methods Clinical data of 3 pediatric patients with Usher syndrome type Ⅱ diagnosed in Women and Children's Hospital Affiliated to Ningbo University from June 2022 to June 2023 were retrospectively analyzed.Whole exome sequencing was used for genetic diagnosis of patients,and Sanger sequencing technique was used to verify the suspected pathogenic mutations in patients and their family members.Results All three patients had mild to moderate hearing loss in both ears,normal vision,and no vestibular reactions.USH2A gene mutation was detected in patient 1:c.8559-2A＞G/c.1964G＞C(p.C655S)complex heterozygous mutation;in patient 2:c.1644+4A＞G/c.187C＞T(p.R63*)complex heterozygous mutation,and in patient 3:c.13877_13880del(p.Q4626Pfs*7)/c.7232A＞C(p.Q2411P)complex heterozygous mutation.Patient 1 and patient 2 were inherited from their parents,while in patient 3 family members did not receive gene tests.According to the American College of Medical Genetics and Genomics guidelines,USH2A gene c.8559-2A＞G,c.187C＞T(p.R63*)and c.13877_13880del(p.Q4626Pfs*7)were rated as pathogenic mutations;USH2A gene c.1644+4A＞G was rated as a possible pathogenic variation;USH2A gene c.1964G＞C(p.C655S)and c.7232A＞C(p.Q2411P)were rated as unknown mutations of clinical significance;while c.1964G＞C(p.C655S)variation was not reported or included in the literature and database.Conclusion USH2A gene complex heterozygous variation may be the cause of deafness in 3 patients.These studies not only enrich the variation spectrum of USH2A gene,but also provide reference for clinical diagnosis.