Targeted exome sequencing identified a novel USH2A mutation in a Chinese usher syndrome family: a case report

Abstract

Background Usher syndrome is a disease with a heterogeneous phenotype and genotype. Our purpose was to identify the gene mutation in a Chinese family with Usher syndrome type 2 and describe the clinical features. Case presentation A 23-year-old man complained of a 10-year duration of nyctalopia and a 3-year decline in visual acuity of both eyes accompanied by congenital dysaudia. To clarify the diagnosis, the clinical symptoms were observed and analysed in combination with comprehensive ophthalmologic examinations as well as genetic analysis (targeted exome sequencing, TES). A typical clinical presentation of Usher syndrome of the fundus was found, including a waxy yellow-like disc, bone-spicule formations and retinal vessel stenosis. Optical coherence tomography (OCT) and optical coherence tomography angiography (OCTA) showed loss of the ellipsoid zone and a reduction in paracaval vessel density in both eyes. Genetic analysis identified a novel homozygous c.8483_8486del (p.Ser2828*) mutation in USH2A. The mutation resulted in premature termination of translation and caused the deletion of 19 fibronectin type 3 domains (FN3), transmembrane (TM) region and PDZ-binding motif domain, which play an important role in protein binding. After combining the clinical manifestations and genetic results, the patient was diagnosed with Usher syndrome type 2. Conclusion We found a novel c.8483_8486del mutation in the USH2A gene through TES techniques. The results broaden the spectrum of mutations in Usher syndrome type 2 and suggest that a combination of clinical information and molecular diagnosis via TES could help Usher syndrome patients obtain a better diagnosis.

USH2A Mutation is Associated With Tumor Mutation Burden and Antitumor Immunity in Patients With Colon Adenocarcinoma

“…The protein exists in the basement membrane and may play an important role in the development and homeostasis of the inner ear and retina ( Weston et al, 2000 ). USH2A mutations are associated with Usher syndrome type IIa, retinitis pigmentosa ( Xing et al, 2020 ), and tongue squamous cell carcinoma ( Zhang et al, 2020 ). In lung adenocarcinoma, the USH2A mutation is one of the most frequently mutated genes for predicting neoantigens ( Cai et al, 2018 ).…”

Novel mutations of the USH2A gene cause Usher syndrome in five Chinese families

“…Considering that these genes contain a large number of coding exons, TES represents a rapid, high-throughput and efficient screening strategy for RP and USH [ 9 ]. We used TES to target 381 known causative genes of inherited retinal disorders as an efficient way to perform gene screening [ 5 ].…”

“…Targeted exome sequencing (TES) was performed for 5 study participants. A total of 381 known genes associated with inherited retinal diseases (IRDs), including USH, were selected by a gene capture strategy using the GenCap custom enrichment kit following the manufacturer’s protocol [ 5 ]. The biotinylated capture probes (80–120-mer) were designed to tile all of the exons with nonrepeated regions.…”

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“…The protein exists in the basement membrane and may play an important role in the development and homeostasis of the inner ear and retina (Weston et al, 2000). USH2A mutations are associated with Usher syndrome type IIa, retinitis pigmentosa (Xing et al, 2020), and tongue squamous cell carcinoma (Zhang et al, 2020). In lung adenocarcinoma, the USH2A mutation is one of the most frequently mutated genes for predicting neoantigens (Cai et al, 2018).…”