Cognitive and language anomalies in two brothers with a rare form of genetic abnormality (deletion of 9p24)

Abstract Two brothers, ages 7 and 9, had an identical rare genetic abnormality: deletion of a segment of chromosome nine (9p monosomy). Neuropsychological evaluation revealed similar patterns of cognitive anomalies involving general retardation of intellectual capabilities and specific problems with the production of behavior including speech articulation and graphomotor skills. The findings suggest that a specific region of chromosome nine is crucial to the development of normal brain function as reflected by cognitive and language skills. Although CT and MRI studies of the subjects were normal, the pattern of cognitive deficits suggests that the frontal lobes may be at particular risk in 9p monosomy.