Frequencies of chromosomal abnormalities at amniocentesis : Over 20 years of cytogenetic analyses in one laboratory.
Prenatal diagnosis of chromosomal disorders has been performed for more than 20 years, mainly for advanced maternal age.
Chromosomal abnormality rates derived from second trimester amniocentesis have mainly come from a collection of small-scale studies from North America and Western Europe.
Accurate risk estimates for chromosomal abnormalities are important tools for the physician or obstetrician who would need to make referrals to a prenatal genetic center.
This paper presents amniocentesis rates of clinically significant cytogenetic abnormalities for various indications, including advanced maternal age, previous chromosomal abnormality, parental structural rearrangement and a family history of aneuploidy as defined in the text.
These data come from a Canadian prenatal diagnosis laboratory with more than 20 years experience in second trimester cytogenetic analysis.
They show that the overall frequency of chromosomal abnormalities for advanced maternal age (>=35 years) is 1.79%. In this group, 21% of all abnormalities are structural rearrangements (including markers) and less than half of all abnormalities are trisomy 21.
The advanced maternal age specific risk of aneuploidies at second trimester is 1.24%. Recurrence risk for aneuploidy after a previous one is 1.29%. However, it is much higher (4.84%) for women of >=35 years.
When a parent's brother, sister, nephew or niece is affected, the risk of occurrence of aneuploidies (0.24%) is not elevated. (...)
Mots-clés Pascal : Amniocentèse, Homme, Diagnostic, Prénatal, Conseil génétique, Aberration chromosomique, Exploration, Cytogénétique, Canada, Amérique du Nord, Amérique, Age mère 35, Incidence, Epidémiologie
Mots-clés Pascal anglais : Amniocentesis, Human, Diagnosis, Prenatal, Genetic counseling, Chromosomal aberration, Exploration, Cytogenetics, Canada, North America, America, Maternal age 35, Incidence, Epidemiology
Notice produite par :
Inist-CNRS - Institut de l'Information Scientifique et Technique
Cote : 99-0120423
Code Inist : 002B23A. Création : 16/11/1999.