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Preconceptional and prenatal screening for fragile X syndrome: Experience with 40 000 tests
Author(s) -
Berkenstadt Michal,
RiesLevavi Liat,
Cuckle Howard,
Peleg Leah,
Barkai Gad
Publication year - 2007
Publication title -
prenatal diagnosis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.956
H-Index - 97
eISSN - 1097-0223
pISSN - 0197-3851
DOI - 10.1002/pd.1815
Subject(s) - fragile x syndrome , family history , fragile x , medicine , prenatal diagnosis , fetus , obstetrics , pediatrics , pregnancy , genetics , biology , psychiatry , gene
Abstract 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. Copyright © 2007 John Wiley & Sons, Ltd.