Clin Exp Otorhinolaryngol.  2013 Mar;6(1):41-44.

A Novel Frameshift Mutation of the USH2A Gene in a Korean Patient with Usher Syndrome Type II

• Boo SH
• Song MJ
• Kim HJ
• Cho YS
• Chu H
• Ko MH
• Chung WH
• Kim JW
• Hong SH

Abstract

Usher syndrome type II (USH2) is the most common form of Usher syndrome, characterized by moderate to severe hearing impairment and progressive visual loss due to retinitis pigmentosa. It has been shown that mutations in the USH2A gene are responsible for USH2. The authors herein describe a 34-year-old Korean woman with the typical clinical manifestation of USH2; she had bilateral hearing disturbance and progressive visual deterioration, without vestibular dysfunction. Molecular genetic study of the USH2A gene revealed a novel frameshift mutation (c.2310delA; Glu771LysfsX17). She was heterozygous for this mutation, and no other mutation was found in USH2A, suggesting the possibility of an intronic or large genomic rearrangement mutation. To the best of our knowledge, this is the first report of a genetically confirmed case of USH2 in Korea. More investigations are needed to delineate genotype-phenotype correlations and ethnicity-specific genetic background of Usher syndrome.

Keyword

Usher syndrome type II; USH2A; Mutation; Frameshift; Korea

MeSH Terms

Female
Frameshift Mutation
Genetic Association Studies
Hearing
Hearing Loss
Humans
Introns
Korea
Molecular Biology
Retinitis Pigmentosa
Usher Syndromes

Figure

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  Fig. 1 Pure tone audiogram of the patient shows moderate hearing loss with a descending pattern (A). The fundoscopic finding of both eyes showed typical pigmentary degeneration with multiple bone spicule pigmentations in over the entire retina, attenuated retinal vessels, and a waxy yellowish optic disc. (B) Right, (C) Left. Reprinted from Boo et al. [5] with permission.

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  Fig. 2 Direct sequencing analysis of the USH2A gene revealed a novel frameshift mutation in exon 13 in the patient (arrow, c.2310delA; p.Glu771LysfsX17).

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