Background: Cytogenetic analysis is a valuable investigation in the diagnostic work up of children with suspected chromosomal disorders. The objective of this study was to describe the prevalence of various types of chromosomal abnormalities in Sri Lankan children undergoing cytogenetic analysis.
Methods: Cytogenetic reports of 1554 consecutive children with suspected chromosomal disorders who underwent karyotyping in two genetic centers in Sri Lanka from January 2006 to December 2011 were reviewed retrospectively.
Results: A total of 1548 children were successfully karyotyped. Abnormal karyotypes were found in 783 (50.6%) children. Numerical and structural abnormalities accounted for 90.8% and 9.2%, respectively. Down syndrome was the commonest aneuploidy identifi ed. Other various autosomal and sex chromosomal aneuploidies as well as micro-deletion syndromes were also detected.
Conclusions: The prevalence of chromosomal abnormalities in Sri Lankan children undergoing cytogenetic analysis for suspected chromosomal disorders was relatively higher than that in Caucasian and otherAsian populations.

Key words: aneuploidy;  chromosome aberrations; cytogenetic analysis; karyotypes