Dorsal forebrain anomaly in Williams syndrome.

BACKGROUND: Williams syndrome (WMS) is a rare neurogenetic condition with a behavioral phenotype that suggests a dorsal and/or ventral developmental dissociation, with deficits in dorsal but not the ventral hemispheric visual stream. A shortened extent of the dorsal central sulcus has been observed in autopsy specimens.
OBJECTIVE: To compare gross anatomical features between the dorsal and ventral portions of the cerebral hemispheres by examining the dorsal extent of the central sulcus in brain magnetic resonance images from a sample of subjects with WMS and age- and sex-matched control subjects.
SUBJECTS: Twenty-one subjects having clinically and genetically diagnosed WMS (mean +/- SD age, 28.9 +/- 7.9 years) were compared with 21 age- and sex-matched typically developing controls (mean +/- SD age, 28.8 +/- 7.9 years).
DESIGN: High-resolution structural magnetic resonance images were acquired. The extent of the central sulcus was qualitatively assessed via surface projections of the cerebral cortex.
RESULTS: The dorsal central sulcus is less likely to reach the interhemispheric fissure in subjects with WMS than in controls for both left (P< .001, chi(2) = 15.79) and right (P< .001, chi(2) = 12.95) hemispheres. No differences between the groups were found in the ventral extent of the central sulcus.
CONCLUSIONS: Anomalies in the dorsal region in patients with WMS are indicative of early neurodevelopmental problems affecting the development of the dorsal forebrain and are most likely related to the deficits in visuospatial ability and behavioral timing often observed in this condition.