USH2A mutations identified by massively parallel sequencing in 3 children with sensorineural hearing loss

～The importance of genetic counseling and genetic testing in Usher syndrome～

Abstract

　　With the widespread implementation of newborn hearing screening (NHS) in Japan, earlier diagnosis of mild to moderate, as well as severe to profound, congenital hearing loss (HL) has become possible. The genetic causes of HL in many cases have been identified even in early childhood by genetic testing for HL. We identified mutations in the USH2A gene that cause Usher syndrome, type 2 (USH2), in three siblings under 10 years old, by massively parallel DNA sequencing analysis. All the three children have non-progressive moderate to severe sensorineural HL with a high-frequency sloping configuration, which is the typical hearing pattern of USH2. None has exhibited any vestibular symptoms or visual abnormalities until now. USH2 cases usually have normal vestibular function, and onset of retinitis pigmentosa (RP) usually occurs in the second decade of life or later; we diagnosed all the children as having USH2. We could provide genetic counseling on the risk of future visual disturbance and the applicable educational support to these patients and their families. Early diagnosis of syndromic HL by genetic testing may be useful, in addition to the NHS program, for appropriate clinical management and educational guidance.