Williams syndrome (WS) is a developmental disorder that includes poor visuospatial constructive cognition. This syndrome has been studied to identify genes important for human cognitive development. Two families are described which have a partial WS phenotype; affected members have the specific WS cognitive profile and vascular disease, but lack other WS features. Submicroscopic chromosome 7q11.23 deletions cosegregate with this phenotype in both families. DNA sequence analyses of the region affected by the smallest (63.6 kb) deletion revealed two genes, elastin (ELN) and LIM-kinase 1 (LIMK1). The latter encodes a novel protein kinase with LIM domains and is strongly expressed in the brain. Because ELN mutations cause vascular disease but not cognitive abnormalities, these data implicate LIMK1 hemizygosity in impaired visuospatial constructive cognition.
DIAGNOSIS OF WILLIAMS SYNDROME AND WILLIAMS SYNDROME COGNITIVE PROFILE BY ANALYSIS OF THE PRESENCE OR ABSENCE OF A LIM-KINASE GENE