Cytogenetic and epidemiological profiles of Down syndrome in a Moroccan population: a report of 852 cases

Abstract

Introduction: Trisomy 21 or Down syndrome is the most common type of autosomal chromosome abnormality, with an incidence of one out of 700 live births. Down syndrome is associated with psychomotor delay, characteristic facial features, and sometimes, cardiac, digestive and ocular malformations. The aim of this study was to estimate the proportions of various cytogenetic types of trisomy 21, and to study the link between maternal age and trisomy 21 in the Moroccan population, in order to provide data on the cytogeneticity and epidemiology of Down syndrome in Morocco.

Methods: A retrospective analysis was performed on the case records of 852 patients who were confirmed as Down syndrome by cytogenetic analysis at the Department of Medical Genetics, National Institute of Health, Morocco.

Results: Among the 852 cases of Down syndrome presenting over a period of 15 years, free trisomy 21 was present in 820 cases (96.24 percent). 27 patients had translocation and five cases were mosaics. The median maternal age of the Moroccan mothers at the birth of the affected child was 35.39 years.

Conclusion: The identification of specific types of chromosomal abnormalities in Down syndrome children is important as it assists with patient management and family counselling.