Israni, Anil VasudevMandal, Anirban2026-02-092026-02-092017https://hdl.handle.net/20.500.14572/4595Anil Vasudev Israni Maxcure Suyosha Woman & Child Hospital, Hyderabad, Telangana 500081 Anirban Mandal Sitaram Bhartia Institute of Science and Research, New Delhi 110016Abstract: The phenotypic expression in DS is determined by the type of underlying cytogenetic abnormality. Almost 90-95% cases of DS are due to pure trisomy of the 21st chromosome; 6-7% is the result of mosaicism and in only 3-5% of cases it results from Robertsonian translocation (ROB). About 1/3rd cases of unbalanced Robertsonian translocation causing DS are inherited. We report a 1-year-old-boy with DS secondary to rea(21;21) ROB.en-USAneuploidypre-conception genetic diagnosisgenetic counsellingtrisomyArticle