Abstract
BACKGROUND: Fragile X is the most common cause of mental retardation after Down syndrome. It is the commonest inherited cause of mental retardation, and results from a dynamic mutation in a gene on the long arm of the X chromosome. Various strategies are used for prenatal screening. OBJECTIVES: To determine whether pre-conceptual or antenatal screening for Fragile X carrier status in apparently low risk women confers any additional benefit over the existing practice of offering testing to women thought to be at increased risk. SEARCH STRATEGY: We searched the Cochrane Pregnancy and Childbirth Group trials register (November 2001), the Cochrane Controlled Trials Register (The Cochrane Library Issue 3, 2001), MEDLINE (1980 to 2001), and reference lists of articles. SELECTION CRITERIA: Randomised clinical trials comparing women being tested regardless of family history (intervention group) with women tested only when there is a family history of either fragile X and/or other undiagnosed mental illness/impairment (control group). DATA COLLECTION AND ANALYSIS: Three reviewers independently assessed trial quality and extracted data. MAIN RESULTS: No trials were included. REVIEWER'S CONCLUSIONS: No information is available from randomised trials to indicate whether routine pre-conceptual or antenatal screening for fragile X carrier status confers any benefit over testing women thought to be at increased risk.