DISTAL 8P DELETION (8)(P23.1) - AN EASILY MISSED CHROMOSOMAL ABNORMALITY THAT MAY BE ASSOCIATED WITH CONGENITAL HEART DEFECT AND MENTAL-RETARDATION

We describe the clinical manifestations and molecular cytogenetic anal yses of three patients with a similar distal deletion of chromosome 8. Each child had mild developmental delay and subtle minor anomalies, T wo had cardiac anomalies but no other major congenital anomalies were present. High resolution G and R banding showed in all three patients del(8)(p23.1), but the breakpoint in case 1 was distal to 8p23.1, in c ase 2 was in the middle of 8p23.1, and in case 3 proximal to 8p23.1, F luorescence in situ hybridization (FISH) studies with a chromosome 8 p aint probe confirmed that no other rearrangement had occurred. FISH wi th a chromosome 8-specific telomere probe indicated that two patients had terminal deletions, Chromosome analysis of the parents of case 1 a nd mother of case 2 were normal; the remaining parents were not availa ble for study. Thirteen individual patients including the three in thi s study, and three relatives in one family with del(8)(p23.1), have be en reported in the past 5 years. Major congenital anomalies, especiall y congenital heart defects, are most often associated with a breakpoin t proximal to 8p23.1, Three patients were found within a 3-year period in this study and five cases were found within 4 years by another gro up, indicating that distal 8p deletion might be a relatively common ch romosomal abnormality, This small deletion is easily overlooked (i.e., cases 1 and 2 were reported as normal at amniocentesis) and can be as sociated with few or no major congenital anomalies. (C) 1996 Wiley-Lis s, Inc.