1p microdeletion in sibs with minimal phenotypic manifestations

We report on two sibs with a paracentric inversion of chromosome 1 [inv(1)( p22.3p34.1)] and a small deletion of the same chromosome (p34.1-->p34.3). T hey presented with learning disabilities and disturbed conduct but lacked t he more severe manifestations usually associated with autosomal chromosome deletion. Born to an alcoholic mother and later placed in foster care becau se of abuse and neglect, the behavior abnormalities they present are likely to be associated with their traumatic postnatal experience. Microscopic de letions without significant morphological phenotypic expression have been d escribed but are rarely reported. Most reported cases of interstitial delet ion of Ip had associated malformations and psychomotor retardation. These s ibs may represent the first evidence that deletion of 1p34.1-->1p34.3 may h ave little impact on the phenotype. (C) 1999 WiIey-Liss, Inc.