Dorsal dimelia in patau syndrome: a case report.

We present a case of a child with Patau syndrome that exhibits features consistent with congenital palmar nail syndrome. The literature is reviewed and evidence presented to demonstrate that this is a defect in the dorso-ventral patterning of the limb and thus a form of dorsal dimelia. In order to differentiate this from other instances of ectopic nail tissue we suggest congenital palmar nail syndrome should be more specifically defined as duplicated nails, absent flexion creases, non-glabrous skin on the palmar surface, reduced movement at the interphalangeal joints and hypoplastic terminal phalanges.