Endocrine Abstracts

Trisomy 21 or Down syndrome is the most common autosomal aneuploidy and the leading genetic cause of intellectual disability worldwide. It is a genetic disease, resulting from the presence of a supernumerary chromosome for the 21st chromosomal pair. It is responsible for a phenotype associating a dysmorphic syndrome, malformations (cardiac, digestive, urinary\..), psychomotor retardation, and can be accompanied by other pathologies and complications (epilepsy, leukemia\..). We report here the results of a retrospective study conducted at the Medical Genetics Department of the Ibn Rochd University Hospital in Casablanca, from January 2003 to December 2018, with the aim of studying the clinical and cytogenetic aspects of trisomy 21, assessing the risk factors, and highlighting the role of genetic counseling and medical and paramedical management of this syndrome. The study identified 262 cases followed for suspected trisomy 21. Among these 262 cases, we retained 64 patients with trisomy 21 confirmed by standard karyotype. The ratio was 3 boys to 4 girls. The average age at diagnosis was 4 years and 7 months. The average age of the mothers giving birth to these patients was 32.54 years. The major clinical signs in the study population were facial dysmorphia, cardiac abnormalities, hypotonia, psychomotor retardation and intellectual disability. Karyotype results showed that 92.19% of the patients had free and homogeneous trisomy21, 6.25% had mosaic trisomy, and 1.56% had unbalanced translocation. Early and multidisciplinary care by health professionals is essential to improve the quality of life of the trisomic 21 child and his or her family. On the other hand, genetic counselling must be systematic, in order to calculate the risk of recurrence, and to propose a possible prenatal diagnosis.

Keywords: Trisomy 21, genetic counseling, prenatal diagnosis.