Recently, Butler et al. [2005; J Med Genet 42:318-321] reported the presence of heterozygous germline mutations in the PTEN tumor suppressor gene in three children with autism and macrocephaly. Here, we report the presence of PTEN mutations in two additional unrelated children with macrocephaly and autism. Our findings extend those of Butler et al. and suggest that PTEN gene sequencing should be included in the genetic evaluation of this subset of autistic individuals.

Arithmetic skills and their cognitive correlates were studied in 24 children with myelomeningocele and shunted hydrocephalus (MM), 27 children with severe traumatic brain injuries (TBI), and 26 children with orthopedic injuries (OI). Their average age was 11.56 years (SD = 2.36). They completed the WRAT-3 Arithmetic subtest and a subtraction task consisting of 20 problems of varying difficulty, as well as measures of working memory, declarative memory, processing speed, planning skills, and visuospatial abilities. The MM group performed more poorly on the WRAT-3 Arithmetic subtest and the subtraction task than the other two groups, which did not differ from each other on either measure. The groups did not differ in the number of math fact errors or visual-spatial errors on the subtraction task, but the MM group made more procedural errors than the OI group. The five cognitive abilities explained substantial variance in performance on both arithmetic tests; processing speed, working memory, declarative memory, and planning accounted for unique variance. Exploratory analyses showed that the cognitive correlates of arithmetic skills varied across groups and ages. Congenital and acquired brain disorders are associated with distinct patterns of arithmetic skills, which are related to specific cognitive abilities.

Examined verbal learning and memory in children with myelomeningocele using the California Verbal Learning Test (CVLT). Participants included 41 children with myelomeningocele, 8 to 15 years of age, 33 of whom had a history of shunted hydrocephalus, and 41 matched, unaffected controls. Children with myelomeningocele and shunted hydrocephalus performed worse than controls on the CVLT. They recalled as many words as controls on the first learning trial, but acquired words more slowly across trials, so that their overall recall was lower. Their learning was characterized by a pronounced recency effect. Their delayed recall of the original list was worse than controls, but not their recognition. Performance of children with myelomeningocele but without shunts was generally not significantly different from that of the other two groups, although they did demonstrate better long-delay free recall than children with shunts. Myelomeningocele is associated with significant retrieval problems when accompanied by shunted hydrocephalus.

Myelomeningocele is a common developmental malformation of the central nervous system that usually results in motor deficits. Previous studies of myelomeningocele have not examined motor adaptation, which involves changes in the control of movements that occur as a result of repeated task exposure but do not depend on conscious recall of the exposure. We studied motor adaptation in 17 children with myelomeningocele and shunted hydrocephalus, 19 children with attention deficit/hyperactivity disorder (ADHD), and 20 healthy siblings. All children were 8 to 15 years of age. They were administered 2 measures of motor adaptation known to be sensitive to subcortical abnormalities in adult neurological disorders. One task assessed the biasing in weight judgments that occurs after exposure to heavy versus light weights, and the other assessed the adaptation in reaching movements that occurs when vision is laterally displaced by prisms. Contrary to expectations, the groups did not differ in motor adaptation. Children in all 3 groups displayed significant biasing in their weight judgments and improvement in the accuracy of pointing during prism adaptation trials. Performance on the 2 motor adaptation tasks was not related to age or IQ. Weight biasing was positively related to a measure of response disinhibition. The findings suggest that myelomeningocele does not result in global impairment of motor skills, but instead in a profile of intact and impaired motor functions that potentially may be decomposed in accordance with the neuroscience of motor skills.