Klinefelter twins presenting with discordant aneuploidies, acardia, forked umbilical cord and with different gonadal sex despite monozygosity

A higher frequency of twin births in sibships of Klinefelter syndrome patients and also monozygotic or dizygotic twins, themselves being affected by Klinefelter syndrome have been noted repeatedly. To address this issue, we evaluated type and frequency of twinning among Klinefelter fetuses that we had received for autopsy within a ‘Prenatal Diagnosis’ program.