Sweat pore count, hair density and tooth size: heritability and genetic correlation.

In 109 subjects from 50 families without major inherited disorders, sweat pore count showed the anticipated reduction with age but also unexpected systematic differences between sides and between fingers. After adjustment for age and sex, significant genetic variation was found for sweat pore count, hair density and tooth size. The three traits were not phenotypically correlated but there was a significant negative genetic correlation between hair density and sweat pore count. The findings suggest that the same genes influence these two traits in opposite directions and that genetic and environmental influences may act on them through different physiological mechanisms.