Cytogenetic analysis and genetic counseling of patients with Down syndrome

V. Plaiaşu, G. Motei, F. Nedelea, E. Neagu, A. Costin

Abstract: The aim of this study was to confirm the presence of Down syndrome (DS) using cytogenetic testing and to assess the inheritance using parental karyotype, as a basis for predicting the risk of recurrence and for genetic counseling. A total of 114 cases suspected to have Down syndrome were included during a period of 18 months from the Department of Medical Genetics of IOMC “Prof Dr Alfred Rusescu”. All this 114 cases suspected to have Down syndrome undergo clinical assessment. Samples were collected and cytogenetic analysis was performed in 96 patients. Chromosomal abnormalities were confirmed in all of the patients that were analyzed by cytogenetic techniques. Most of the children with DS were born to mothers under 35 years old and were the second born in the birth order. Though advanced maternal age is an established risk factor for DS, this study revealed an increased number of DS babies born to the young mothers. Karyotypes collected from children and their parents, family history and parental ages had a crucial contribution in providing genetic counseling, prenatal diagnosis and estimating the risk for the next conception. Prenatal diagnosis should be offered to all mothers at risk: > 35 years or younger mothers, if the karyotype analysis indicates an altered chromosomal pattern. Prenatal cytogenetic analysis from chorionic villi or amniotic fluid could provide early and reliable diagnosis, and help the family to avoid the recurrence.
Keywords: Down syndrome, karyotype, trisomy, mosaicism, translocation, counseling