Parihar, MayurKoshy, BeenaSrivastava, Vivi Miriam2015-03-052015-03-052013-07Parihar Mayur, Koshy Beena, Srivastava Vivi Miriam. Mosaic double aneuploidy: Down syndrome and XYY. Indian Journal of Human Genetics. 2013 July-Sept ;19 (3): 346-348.http://imsear.searo.who.int/handle/123456789/156589Chromosomal abnormalities are seen in nearly 1% of live born infants. We report a 5‑year‑old boy with the clinical features of Down syndrome, which is the most common human aneuploidy. Cytogenetic analysis showed a mosaicism for a double aneuploidy, Down syndrome and XYY. The karyotype was 47, XY,+21[19]/48, XYY,+21[6]. ish XYY (DXZ1 × 1, DYZ1 × 2). Mosaic double aneuploidies are very rare and features of only one of the aneuploidies may predominate in childhood. Cytogenetic analysis is recommended even if the typical features of a recognized aneuploidy are present so that any associated abnormality may be detected. This will enable early intervention to provide the adequate supportive care and management.enDisorder of sexual developmentdouble aneuploidyDown syndrome with XYYmeiotic non‑disjunctionmosaicAneuploidyChild, PreschoolChromosomes, Human, X --geneticsChromosomes, Human, Y --geneticsDisorders of Sex Development --geneticsDown Syndrome --epidemiologyDown Syndrome --geneticsHumansMaleSex Chromosome AberrationsSex Chromosome Disorders of Sex Development --geneticsArticle