Oro-facial-digital syndrome IX with severe microcephaly: a new variant in a genetically isolated population.

We describe four patients, two pairs of siblings, with a somewhat unique oro-facial-digital syndrome. The siblings come from the Navajo population which has undergone several genetic "bottlenecks." Thus, as would be anticipated, this syndrome seems to show autosomal recessive inheritance. The combination of the presence of retinal colobomata and the paucity of digital findings in these patients leads us to believe that their condition is best described as a variant of oro-facial-digital syndrome IX. In addition to retinal colobomata, these patients also show severe microcephaly, mental retardation and short stature.