Deletion of a single chromosome band 4q26 in a malformed girl: exclusion of Rieger syndrome associated gene(s) from the 4q26 segment.

We report a malformed girl with a single chromosome band deletion of 4q26 in peripheral lymphocytes. This patient is the fourth case reported with an interstitial deletion involving 4q26 and has the smallest deletion of those reported. Deletion mapping indicates that psychomotor retardation, coloboma, prominent forehead, epicanthus, broad based nose, and broad, thin upper lip are associated with monosomy 4q26, and that gene(s) associated with Rieger syndrome can be excluded from the 4q26 segment.