FMR1 CGG expansions: Prevalence and sex ratios. Issue 5 (5th June 2013)

• Record Type: Journal Article
• Authors: Maenner, Matthew J.; Baker, Mei W.; Broman, Karl W.; Tian, Jianan; Barnes, Janel K.; Atkins, Anne; McPherson, Elizabeth; Hong, Jinkuk; Brilliant, Murray H.; Mailick, Marsha R.
• Is Part Of: American journal of medical genetics. Volume 162:Issue 5(2013)
• Page Start: 466
• Page End: 473
• Publication Date: 2013-06-05
• Subjects: Neuropsychiatry -- Periodicals; Medical genetics -- Periodicals; 616.8904205
• DOI: 10.1002/ajmg.b.32176
• Languages: English
• ISSNs: 1552-4841

Abstract

<abstract abstract-type="main" xml:lang="en"> <title>Abstract</title> <sec id="ajmgb32176-sec-0001" sec-type="section"> <p>We have estimated the prevalence of FMR1 premutation and gray zone CGG repeat expansions in a population‐based sample of 19, 996 male and female adults in Wisconsin and compared the observed sex ratios of the prevalence of FMR1 CGG premutation and gray zone expansions to theoretical sex ratios. The female premutation prevalence was 1 in 148 and comparable to past research, but the male premutation prevalence of 1 in 290 is somewhat higher than most previous estimates. The female:male premutation prevalence ratio is in line with the theoretically predicted sex ratio. The prevalence of CGG repeats in the gray zone (45–54 repeats) was 1 in 33 females and 1 in 62 males. The prevalence of the "expanded" gray zone (defined here as 41–54 CGG repeats) was 1 in 14 females and 1 in 22 males, leading to a female:male ratio of 1.62 (95% confidence interval 1.39–1.90). This female:male ratio was significantly lower than the expected ratio of 2.0. We examined results from three previously published <italic>FMR1</italic> prevalence studies and found similar female:male ratios for CGG repeats in this "expanded" gray zone range (pooled female:male ratio across all four studies 1.66, 95% confidence interval 1.51–1.82). Further research is needed to understand the apparent excess prevalence of males with CGG repeats in this range. © 2013 Wiley Periodicals, Inc.</p> </sec> </abstract>