OBJECTIVES: To determine the carrier frequency of fragile X syndrome, and the rate of expansion from premutation (PM) carrier to full mutation (FM) fetus. METHODS: Results were analyzed on women with no family history of fragile X syndrome, or who were PM/FM carriers, who were tested between January 1994 and June 2004. PM was defined 55-199 repeats, FM above 200. RESULTS: Out of 40 079 women screened, 5 FM and 255 PM carriers were detected. There was no significant difference in carrier frequency between those with versus those without family history of mental retardation or developmental abnormalities: 1 in 128 (28/3596) versus 1 in 157 (232/36 483). However, the median of repeats differed significantly: 58 and 66 repeats, respectively, (P < 0.0001). Invasive prenatal diagnosis was carried out in 370 pregnancies (7 FM and 363 PM). Thirty FM fetuses were detected. There was a lower expansion rate in cases without a family history: 10% (17/169 PMs) compared to 50% (11/22 PMs) in those with a history, but this could be accounted for by the difference in allele size. CONCLUSION: There is now sufficient information on screening parameters and prenatal diagnosis of fragile X syndrome to offer testing to women of reproductive age.
OBJECTIVES: To determine the carrier frequency of fragile X syndrome, and the rate of expansion from premutation (PM) carrier to full mutation (FM) fetus. METHODS: Results were analyzed on women with no family history of fragile X syndrome, or who were PM/FM carriers, who were tested between January 1994 and June 2004. PM was defined 55-199 repeats, FM above 200. RESULTS: Out of 40 079 women screened, 5 FM and 255 PM carriers were detected. There was no significant difference in carrier frequency between those with versus those without family history of mental retardation or developmental abnormalities: 1 in 128 (28/3596) versus 1 in 157 (232/36 483). However, the median of repeats differed significantly: 58 and 66 repeats, respectively, (P < 0.0001). Invasive prenatal diagnosis was carried out in 370 pregnancies (7 FM and 363 PM). Thirty FM fetuses were detected. There was a lower expansion rate in cases without a family history: 10% (17/169 PMs) compared to 50% (11/22 PMs) in those with a history, but this could be accounted for by the difference in allele size. CONCLUSION: There is now sufficient information on screening parameters and prenatal diagnosis of fragile X syndrome to offer testing to women of reproductive age.
Authors: Marsha Mailick Seltzer; Mei Wang Baker; Jinkuk Hong; Matthew Maenner; Jan Greenberg; Daniel Mandel Journal: Am J Med Genet B Neuropsychiatr Genet Date: 2012-05-22 Impact factor: 3.568
Authors: Alice G Ames; Alice Jaques; Obioha C Ukoumunne; Alison D Archibald; Rony E Duncan; Jon Emery; Sylvia A Metcalfe Journal: Health Expect Date: 2012-10-15 Impact factor: 3.377
Authors: Sarah L Nolin; Sachin Sah; Anne Glicksman; Stephanie L Sherman; Emily Allen; Elizabeth Berry-Kravis; Flora Tassone; Carolyn Yrigollen; Amy Cronister; Marcia Jodah; Nicole Ersalesi; Carl Dobkin; W Ted Brown; Raghav Shroff; Gary J Latham; Andrew G Hadd Journal: Am J Med Genet A Date: 2013-02-26 Impact factor: 2.802