Smith-Fineman-Myers syndrome in apparently monozygotic twins.

We report on two boys, monozygotic twins born to normal and nonconsanguineous parents, presenting with an unusual facial appearance, cortical atrophy, dolichocephaly, short stature, cleft palate, micrognathia, prominent upper central incisors, bilateral Sidney line, minor foot deformities, unstableness in walking, early hypotonia, hyperreflexia, hyperactivity, psychomotor retardation, and severe delay in language development. These manifestations resemble those previously described in the Smith-Fineman-Myers syndrome.