[Study of a group of families with high incidence of schizophrenia]

The pedigrees of six schizophrenics' families presenting a very high percentage of sick subjects, (near to 50%) are studied. The data obtained allow to think to an hereditary transmission of the mental disease, in these families, as an autosomal dominant character; the responsible gene may have a reduced penetrance and a variable expressivity. The comparison of these data with those obtained from other schizophrenics' families support the hypotesis of an unomogeneus genetic basis for schizophrenia and also the supposition that a severe mutation of the principal gene has occurred in the studied families.