Macular Degeneration Associated With Aberrant Expansion of Trinucleotide Repeat of the SCA7 Gene in 2 Japanese Families

Abstract

To evaluate the macular function of Japanese patients with a trinucleotide repeat expansion in the spinocerebellar ataxia type 7 (SCA7) gene. Methods: Ophthalmic findings in patients whose DNA analysis revealed expanded alleles of the trinucleotide repeat in the SCA7 gene were evaluated. Results: Trinucleotide repeat was expanded from 40 to 48 in affected patients (control subjects, 12 repeats). Affected patients were characterized by different degrees of visual acuity decrease (0.09-0.9), a tritan axis color vision, a coarse granular appearance of the macular region on scanning laser ophthalmoscopy, depression of multifocal electroretinograms, and macular degeneration. However, pigmentary changes were not observed

Spinocerebellar Ataxia Type 7 (SCA7) Shows a Cone–Rod Dystrophy Phenotype

“…There have been many reports of the visual disturbances in hereditary spinocerebellar ataxias in the era before molecular diagnoses (reviewed in Harding (1982Harding ( , 1993) and more recent study of SCA7-associated retinopathy (Abe et al, 2000). To complement and extend these earlier investigations and increase understanding of the role that ataxin-7 may play in the human retina, we have characterized in detail with non-invasive tests the retinal function and structure of members of a family with mutations in the SCA7 gene.…”

Unusual Retinal Phenotypes in an SCA7 Family

“…After these reports, many genetic analyses have been performed in Japan. However, SCA7 is rare in Japan, and only three families with SCA7 have been identified to date (7,8). In this paper, we report the cases of the fourth Japanese family with SCA7 and unique retinal degeneration.…”

“…In Japan, SCA7 is a rare disease, and only three familial cases have been reported in the literature (7,8). SCA7 is…”

“…The mean age at onset ranged from 40 to 50 years of age (9)(10)(11) (12). In past reports of SCA7, macular degeneration has been the main clinical feature (8,13 …”

T2-hyperintensity of the Middle Cerebellar Peduncles in a Patient with SCA7

“…A 41-year-old man with spinocerebellar ataxia type 7 (SCA7) noticed a staggering gait at 21 years of age and deterioration of vision at 25 years of age (1). His past medical history revealed no other diseases.…”