Brain abnormalities in Williams syndrome: a review of structural and functional magnetic resonance imaging findings.
Williams syndrome (WS) is rare genetic form of mental retardation caused by a microdeletion on chromosome 7q11.23 that causes cognitive impairment and a variety of physical abnormalities. MRI studies of WS have demonstrated a series of brain abnormalities, including decreased brain size, with a relatively greater decrease in the volume of the cerebral white matter volume as compared to the cerebral gray matter. Moreover there is evidence that the posterior cerebrum is more affected in that persons with WS have a greater ratio of frontal to posterior regional volume. These findings are further supported by automated analyses that have shown reduced gray matter density in the superior parietal lobe areas. Functional MRI studies have demonstrated hypofunction immediately adjacent to, and anterior to, the intraparietal sulcus, a region in which structural brain differences had been identified. These anatomical and functional differences are consistent with the neuropsychological profile of WS - in particular, with evidence of dorsal stream visual processing deficits. To date, however, studies have always been performed in comparison to intellectually average controls. It is not clear, therefore, if findings are specific to the WS population or whether they represent a morphological disturbance characteristic of mental retardation, irrespective of genetic etiology. In this article, we reviewed recent advances underlying the structural and functional neural substrate of WS in Medical Literature Analysis and Retrieval System Online (MEDLINE; 1997-2007).
Jackowski
Andrea Parolin
AP
Laboratório Interdiciplinar de Neurociências Clínicas (LiNC), Universidade Federal de Sao Paulo (UNIFESP), São Paulo, São Paulo, Brazil. jackowski@psiquiatria.epm.br
Rando
Kenneth
K
Maria de Araújo
Célia
C
Del Cole
Carolina Grego
CG
Silva
Ivaldo
I
Tavares de Lacerda
Acioly Luiz
AL
D001921:Brain / Q000002:abnormalities / Q000098:blood supply / Q000473:pathology; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods*; D010100:Oxygen / Q000097:blood; D018980:Williams Syndrome / Q000175:diagnosis* / Q000503:physiopathology*
D010100:Oxygen