Hallucal ridge counts in patients with Klinefelter's syndrome.

Ridges counts of the whorls, distal loops and tibial loops of the hallucal patterns of 85 Klinefelter's syndrome patients (47,XXY) were undertaken. Comparison with counts from normal male and female controls showed that the whorls and distal loops of the Klinefelter's patients had significantly fewer ridges, if the ridge count was limited to the tibial side of the patterns. These findings are in contrast with those of Turner's syndrome cases, in which the hallucal patterns have greater ridge counts than normal subjects. As a result, it is suspected that deficiency or excess of the X chromosome affects the hallucal ridge count as well as the ridge counts of fingers and palms.