Adducted thumb syndromes.

The adducted thumbs syndrome is characterized by cleft palate, microcephaly, and dysmyelination. A fifth case of this syndrome is presented. Several other syndromes which may present with adducted thumbs are reviewed and re-assessed. The original contributions consist of discussions of (1) the possible pathogenesis of adducted thumbs in the congenital clasped thumb syndrome, and (3) the significance of adducted thumbs as a possible marker in sex-linked hydrocephalus.