AUTISM AND MATERNALLY DERIVED ABERRATIONS OF CHROMOSOME 15Q

Of the chronic mental disabilities of childhood, autism is causally le ast well understood, The former view that autism was rooted in exposur e to humorless and perfectionistic parenting has given way to the noti on that genetic influences are dominant underlying factors, Still, ide ntification of specific heritable factors has been slow with causes id entified in only a few cases in unselected series, A broad search for genetic and environmental influences that cause or predispose to autis m is the major thrust of the South Carolina Autism Project, Among the first 100 cases enrolled in the project, abnormalities of chromosome 1 5 have emerged as the single most common cause, The four abnormalities identified include deletions and duplications of proximal 15 q. Other chromosome aberrations seen in single cases include a balanced 13;16 translocation, a pericentric inversion 12, a deletion of 20p, and a ri ng 7, Candidate genes involved in the 15q region affected by duplicati on and deletion include the ubiquitin-protein ligase (UBE3A) gene resp onsible for Angelman syndrome and genes for three GABA(A) receptor sub units, In all cases, the deletions or duplications occurred on the chr omosome inherited from the mother. (C) 1998 Wiley-Liss, Inc.