Association between nondisjunction and maternal age in meiosis-II human oocytes

Journal Article · Mon Jul 01 04:00:00 EDT 1996 · American Journal of Human Genetics

OSTI ID:443750

Dailey, T; Cohen, J; Munne, S; Dale, B

The relationship between advanced maternal age and increased risk of trisomic offspring is well know clinically but not clearly understood at the level of the oocyte. A total of 383 oocytes that failed fertilization from 107 patients undergoing in vitro fertilization were analyzed by FISH using X-, 18-, and 13/21-chromosome probes simultaneously. The corresponding polar bodies were also analyzed in 188 of these oocytes. The chromosomes in the oocyte and first polar body complement each other and provide an internal control to differentiate between aneuploidy and technical errors. Two mechanisms of nondisjunction were determined. First, nondisjunction of bivalent chromosomes resulting in two univalents going to the same pole and, second, nondisjunction by premature chromatid separation (predivision) of univalent chromsomes producing either a balanced (2 + 2) or unbalanced (3 + 1) distribution of chromatids into the first polar body and M-II oocytes. Balanced predivision of chromatids, previously proposed as a major mechanism of aneuploidy, was found to increase significantly with time in culture (P < .005), which suggests that this phenomenon should be interpreted carefully. Unbalanced predivision and classical nondisjunction were unaffected by oocyte aging. In comparing oocytes from women <35 years of age with oocytes from women {ge}40 years of age, a significant increase (P < .001) in nondisjunction of full dyads was found in the oocytes with analyzable polar bodies and no FISH errors. Premature predivision of chromatids was also found to cause nondisjunction, but it did not increase with maternal age. 44 refs., 3 figs., 2 tabs.

• OSTI ID: 443750
• Journal Information: American Journal of Human Genetics, Journal Name: American Journal of Human Genetics Journal Issue: 1 Vol. 59; ISSN AJHGAG; ISSN 0002-9297
• Country of Publication: United States
• Language: English

Related Subjects

55 BIOLOGY AND MEDICINE
BASIC STUDIES
AGE DEPENDENCE
ANEUPLOIDY
CELL DIVISION
CHROMATIDS
DNA HYBRIDIZATION
FLUORESCENCE
HUMAN CHROMOSOMES
KARYOTYPE
MEIOSIS
NON-DISJUNCTION
OOCYTES
STRUCTURE-ACTIVITY RELATIONSHIPS