Visual Function in Carriers of XXXX .

@entity1 @entity227 @entity8105 @entity10289 @entity1939 @entity8099
PURPOSE: To determine the frequency and severity of visual function loss in female carriers of @entity8105 ( @entity8105 ). DESIGN: Case series. @entity1 : Two hundred seventy-six @entity8105 carriers with cross-sectional data (n  = 242) and longitudinal data (n  = 34; median follow-up, 16 years; follow-up range, 3-37 years). Half of the carriers were from @entity8099 - or @entity10289 -genotyped families. METHODS: Retrospective medical records review. MAIN OUTCOME MEASURES: Visual acuities, @entity227 , final dark adaptation thresholds, and full-field electroretinography (ERG) responses to 0.5-Hz and 30-Hz flashes. RESULTS: In genotyped families, 40% of carriers showed a baseline abnormality on at least 1 of 3 psychophysical tests. There was a wide range of function among carriers. For example, 3 of 121 (2%) genotyped carriers were @entity227 , some as young as 35 years. Visual fields were less affected than visual acuity. In all carriers, the average ERG amplitude to 30-Hz flashes was approximately 50% of normal, and the average exponential rate of amplitude loss over time was half that of @entity8105 males (3.7%/year vs. 7.4%/year, respectively). Among obligate carriers with affected fathers, sons, or both, 53 of 55 (96%) had abnormal baseline ERG results. Some carriers who initially had completely normal fundi in both eyes went on to experience moderately @entity227 , although not @entity1939 . Among carriers with @entity8099 mutations, those with mutations in @entity8099 , compared with those in exons 1-14, had worse final dark adaptation thresholds and lower 0.5-Hz and 30-Hz ERG amplitudes. CONCLUSIONS: Most carriers of @entity8105 had mildly or moderately reduced visual function but rarely became @entity1939 . In most cases, obligate carriers could be identified by ERG testing. Carriers of @entity8099 @entity8099 mutations tended to have worse visual function than carriers of @entity8099 exon 1 through 14 mutations. Because @entity8105 carrier ERG amplitudes and decay rates over time were on average half of those of affected @entity1 , these observations were consistent with the Lyon hypothesis of random X-inactivation.
