Hand clasping--an overview]

The literature concerning the asymmetry clasping hands is reviewed based on 192 studies. This paper describes the incidence, sex differences, age differences and genetical problems including twinning. The incidence of left hand clasping ranges from 30% to 75% (mean 43%). The review confirms the so-called east-west-gradient and there is a predominance of the left type in Europe. Age and sex differences are only small. There is only a small relationship between hand clasping and handedness. 18 authors examined hand clasping in families and 4 in twins. The family data suggest that hand clasping may be under genetic control, yet it is clear that no simple genetic model for the inheritance can be applied. Both monozygotic and dizygotic twins show a low concordance and the R-R, R-L and L-L pairs in monozygotic and dizygotic twins are in binomial distribution.