Trigonocephaly: a new familial syndrome.

Trigonocephaly was found in six relatives through three generations of one family. The propositus was ascertained at birth because of omphalocele. In addition to trigonocephaly, he had minor ear, vertebral, and genital abnormalities. His father had mild microcephaly, and both had minor eye abnormalities. None of the other four affected individuals had any other malformations. In this family, trigonocephaly is an autosomal dominant trait. The ratio of affected males to affected females was 5 to 1, and although the paucity of affected females is not statistically significant, we speculate that it may reflect variable expressivity or sex limitation of the trait. We conclude that the condition in this family represents a unique syndrome in which trigonocephaly is not associated with functional brain abnormalities and where craniosynostosis is limited to the metopic region.