This research study will investigate a special type of Down syndrome called translocation Down syndrome. While most children with Down syndrome have an extra copy of chromosome 21, about 3-4% have this extra chromosome material attached to another chromosome, known as a translocation. This form can sometimes be inherited from a parent who carries a balanced translocation.
The aim of the study is to find out how common translocation Down syndrome is among children with confirmed Down syndrome in Assiut, Egypt, and to check whether their parents are carriers of a balanced translocation. Understanding this will help improve family counseling, estimate the chance of recurrence in future pregnancies, and guide genetic screening and prevention strategies.