Twins and Klinefelter's Syndrome

SummaryA multiple birth frequency of 5.59% has been found in 25 Klinefelter sibships, which is statistically significantly higher than expected (P < 0.001).A family investigation of a patient with Klinefelter's syndrome, who is a triplet himself, revealed 5 twin births and 2 triplet births in three generations.The mortality of the 19 children from the 9 multiple births born in the 25 Klinefelter sibships was 53% up to the age of 3. Such a high mortality indicates that some of the twins and triplet births might have suffered from chromosome disorders contributing to the high mortality.If the comparatively high frequency of twins in the sibships with Klinefelter's syndrome as well as Turner's syndrome is confirmed by further studies, this will indicate a relation between the cause of sex chromosome non-disjunction and multiple births or between the predisposition to non-disjunction and multiple births.