• A young woman with features resembling de Lange syndrome had a normal banded karyotype. Similar phenotypes were present in a maternal aunt and uncle. Utilizing high-resolution banding, the propositus was found to have a chromosomal abnormality characterized by dup(4p)del(9p). Using the same banding technique, her mother and two of her siblings were identified as having balanced reciprocal translocations. Chromosome studies with high-resolution banding should be performed in these instances even in the presence of a normal banded karyotype. Determining a chromosomal basis for the phenotype may lead to a significant reproductive risk in individuals with balanced chromosomal rearrangements and may afford them with the opportunity to pursue prenatal diagnosis.
Hersh JH, Dale KS, Gerald PS, Yen FF, Weisskopf B, Dinno ND. Dup(4p)del(9p) in a Familial Mental Retardation SyndromeResemblance to de Lange Syndrome Detected by High-Resolution Banding. Am J Dis Child. 1985;139(1):81–84. doi:10.1001/archpedi.1985.02140030087037