Division of Biostatistics, Washington University School of Medicine, St. Louis, Missouri 63110.
To test if familial transmission of schizophrenia is consistent with a model of monogenic inheritance with a multifactorial background, a mixed-model segregation analysis was applied to Swedish pedigrees consisting of 270 probands in 263 nuclear families. Results of the best-fitting mixed-model solutions are consistent with multifactorial transmission and no major gene. However, numerical instabilities prevented formal hypothesis testing, so an irrefutable genetic mechanism remains unidentified. Alternative research strategies that exploit recent advances in molecular genetics are discussed.