CLINICAL AND MOLECULAR ANALYSES OF DELETION 3P25-PTER SYNDROME

Hemizygous deletion of 3p25-pter is associated with a phenotype of pro found growth failure, microcephaly, characteristic facial changes, and mental retardation. Since the severity may be quite variable, we have studied 3 cases of del 3p25-pter to define the clinical manifestation s and the critical chromosome region for phenotypic expression. The pa tient we now report died at age 6 months and provided an opportunity f or a detailed necropsy analysis for only the second time in a del(3p) patient. He had marked hypoplasia of all organs, hypomyelination of wh ite matter, and multiple renal cortical microcysts. Ordered genomic ma rkers from the distal regions of chromosome 3p aided in determining th e parent of origin of each deletion and in defining the boundaries of the deleted chromosomal segments. The deleted markers distal to the RA FI oneogene in 2 of the 3 patients were consistently hemizygous. One p atient had an interstitial deletion based on evidence of diploid inher itance of one of the most distal loci (D3S17). Available genetic linka ge maps suggest that the deletion spans at least 19 centimorgans (cM). (C) 1993 Wiley-Liss, Inc.