Juvenile X-linked retinoschisis from XLRS1 Arg213Trp mutation with preservation of the electroretinogram scotopic b-wave - 08/09/11
Abstract |
PURPOSE: To present an Arg213Trp missense mutation in the XLRS1 gene in a family with juvenile X-linked retinoschisis in which one affected male had a normal electroretinogram scotopic b-wave amplitude.
METHODS: Two affected males and one unaffected male from this family with X-linked retinoschisis underwent standard clinical examination including an electroretinogram. Mutations in the XLRS1 gene were detected by sequence analysis and by restriction enzyme assay for loss of an MSP-I restriction site.
RESULTS: A missense mutation of C to T at nucleotide position 637 was identified in exon 6 of the XLRS1 gene. This changed the positively charged arginine to a nonpolar tryptophan (Arg213Trp) within the biologically important discoidin domain. Clinical examination revealed intraretinal cysts in a spoke-wheel distribution and early macular atrophy of the retinal pigment epithelium. Whereas the older affected patient had an “electronegative” electroretinogram typical of retinoschisis, the 13-year-old grandson with the same XLRS1 mutation had a normal electroretinogram scotopic b-wave.
CONCLUSION: Although the electroretinogram is a key diagnostic test for X-linked retinoschisis, this report of a normal electroretinogram scotopic b-wave in a male with molecularly confirmed X-linked retinoschisis indicates that caution is advised in relying on the electroretinogram in differential diagnosis of this condition.
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This study was supported by grants R01EY10259, P30-EY07003 (Vision Research Core), and M01RR00042 from the National Institutes of Health, Bethesda, Maryland; The Foundation Fighting Blindness, Hunt Valley, Maryland; a gift from the DiMattia family, Farmington Hills, Michigan; and an RPB Senior Scientific Investigator Award (Dr Sieving), Research to Prevent Blindness, Inc, New York, New York. |
Vol 128 - N° 2
P. 179-184 - août 1999 Retour au numéroBienvenue sur EM-consulte, la référence des professionnels de santé.
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