45,X 46,XX MOSAICISM IN PATIENTS WITH IDIOPATHIC PREMATURE OVARIAN FAILURE/

Objective: To determine whether low-level 45,X/46,XX mosaicism may be present in some women with premature ovarian failure (POF). Design: Sl ide preparations were made from lymphocyte cultures stimulated with ph ytohemagglutinin, and fluorescence in situ hybridization (FISH) was th en performed using a biotin-labeled X-chromosome probe. Setting: Cytog enetics laboratory. Patient(s): Fifteen women with idiopathic POF, 20 age-matched controls, and an additional 10 older control women with no rmal reproductive histories. Intervention(s): Blood samples were colle cted. Main Outcome Measure(s): The number of X chromosomes present in each cell. Result(s): In patients with POF, the percentage of cells wi th a single X chromosome (mean, 5.50) was significantly greater than i n the controls of similar age (mean, 2.42). For control subjects, ther e appeared to be a linear correlation between the number of cells with a single X chromosome and age. Conclusion(s): Some cases of POF may b e attributable to low-level 45,X/46,XX mosaicism, which can be detecte d using FISH. In the lymphocytes from normal women, the rate of accumu lation of cells with a single X chromosome was approximately 700 per 1 0(6) cells per year. (Fertil Steril(R) 1998;70:89-93. (C)1998 by Ameri can Society for Reproductive Medicine.).