Analysis of the structure of developmental delay and intellectual disability among patients of the Research Centre for Medical Genetics

Background: Developmental delay (DD) and intellectual disability (ID) are frequent symptoms in patients consulted by a geneticist. Purpose of the research: evaluation of the structure and variety of nosological forms of DD and ID and their dynamics among patients consulted by geneticists of the counseling unit and research and counseling department of the Research Centre for Medical Genetics in 2006, 2007, 2016 and 2017. Materials and methods: The present work was performed on the material taken from the medical genetic cards of patients of the Research Centre for Medical Genetics consulted by geneticists of the counseling unit and research and counseling department in 2006 and 2007 and 10 years later in 2016 and 2017. The total number of medical genetic cards processed during the 4 analyzed years was 14301 for all nosologies; the total number of cards of patients with DD or ID during the 4 years was 2321 cards. The total number of patients with DD or ID over the 4 analyzed years was 2350. Meanwhile the proportions of patients with DD or ID consulted in 2016-2017 increased significantly compared to the proportions of such patients consulted in 2006-2007. Results: During the research period (2006, 2007, 2016, and 2017) the structure of DD and ID remained almost unchanged for criteria such as gender and age. The proportions of patients with DD or ID caused by environmental factors and genetic causes also did not change. There was a significant increase in the number of patients with DD or ID in 2016 and 2017 with a diagnosis confirmed by biochemical, molecular genetic or cytogenetic methods. The number of nosological forms of PD and OA confirmed by molecular genetic or cytogenetic methods increased almost 5-fold over the ten-year period research. Conclusions: The significant increase in the number of patients with laboratory verified genetic forms of DD or ID in 2016 and 2017 is explained by significant advances in DNA diagnostics of syndromes manifesting in DD or ID, as well as the appearance of new research methods - chromosome microarray analysis and next-generation sequencing.

developmental delay, intellectual disability, chromosomal disorders, monogenic diseases, genomic imprinting disorders

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