Ebstein's anomaly of the heart occurring in a boy with XXY Klinefelter's syndrome is a combination which has not been previously reported. Since many severe congenital heart diseases do not permit survival into puberty, it is possible that the association of Klinefelter's syndrome with congenital heart disease is being missed. It is therefore suggested that a genital evaluation be carried out in all postpubertal boys with congenital heart disease and where possible, buccal smears for sex chromatin be done in all phenotypical males with congenital heart diseases as early as possible.
Rao VS, Mooring PK. Ebstein's Anomaly in XXY Klinefelter's Syndrome. Am J Dis Child. 1970;120(2):164-165. doi:10.1001/archpedi.1970.02100070108017