Academy of Medical Sciences of I.R. Iran Archives of Iranian Medicine 1029-2977 23 5 2020 05 01 Double Trisomy 48,XXY,+21 in a Neonate with Congenital Heart Disease 356 358 10.34172/aim.2020.26 EN Mahdi Bijanzadeh Shahram Rajaei Behbahani Journal Article 10.34172/aim.2020.26 2018 10 17 2019 12 11 Double trisomy 48, XXY, +21 or Down-Klinefelter syndrome is a rare occurrence and presents clinical manifestation of trisomy 21 in early life and of Klinefelter syndrome after 10 months of age. The phenotypic and karyotyping characteristics of a 2-month-old boy were reported. He had mild clinical feature of Down syndrome and echocardiographic features of atrioventricular (AV) septal defects with severe pulmonary valve stenosis.