Single central incisor in familial holoprosencephaly.

Most cases of holoprosencephaly occur sporadically, but occasionally this malformation recurs in a kindred. In a family with two affected children, the father and paternal aunt were found to have single central maxillary incisors and hypotelorism. Family members of children with holoprosencephaly should be carefully examined for these physical findings; their presence may represent evidence for a less severe form of holoprosencephaly that may be transmitted in an autosomal dominant fashion.