Thalidomide Birth Defects Not a Patterning Problem

Phocomelia, a rare, devastating, congenital limb malformation in which long bones are shortened, has been presumed to be a patterning disorder in which genes related to body layout go off-kilter. But Clifford Tabin and colleagues use a chick limb bud X-irradiation model to show that the disorder arises, not from a patterning defect, but from the loss of skeletal progenitor cells.

The demonstration that 'shoulder-to-finger' patterning is unaffected by X-irradiation challenges a classic theory of limb development. Past studies of X-irradiation-induced phocomelia provided corroborative evidence for the progress zone model of development, whereby cell identity is determined by the time spent at the apex of the limb bud or 'progress zone'. However, the current results are the latest in a series that contradict this model.

CONTACT

Clifford Tabin (Harvard Medical School, Boston, MA, USA)
E-mail: tabin@receptor.med.harvard.edu

Abstract available online.

(C) Nature press release.

Message posted by: Trevor M. D'Souza