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.