[Inheritance of psoriasis. Analysis of 2035 family histories].

Detailed pedigrees were established in 2,035 families with psoriasis, including 30 twin pairs, and evaluated by means of computer analysis. The following results on the devolution of psoriasis were drawn: the hypotheses of the irregular dominant and the bifactorial recessive inheritance appear to be inacceptable. The findings suggest a multifactorial etiology of psoriasis with a polygenic mode of inheritance. The risk for relatives to be affected by psoriasis is calculated.