Duchenne Muscular Dystrophy (DMD) is a neurogenetic developmental disorder that presents with progressive muscular weakness. It is caused by a mutation in a gene that results in the absence of specific products that normally localize to muscle cells and the central nervous system (CNS). The majority of affected individuals have IQs within the normal range, generally with lower verbal than performance IQ scores. Prior work has demonstrated selective deficits on tests of verbal span and immediate memory. For the current study, 26 boys with DMD (and normal intellectual function) and their unaffected siblings were evaluated. Paired comparisons demonstrated that the children with DMD had significantly poorer academic achievement scores than their siblings, even though their vocabulary levels and home and educational environments were comparable. Children with DMD also had more behavioral concerns, physical disabilities, and poorer verbal memory spans. Linear regression indicated that behavioral concerns, executive function, and physical disability did not contribute substantially to academic performance, whereas performance on verbal span did. DMD presents with a selective developmental aberration in verbal span that has wide-ranging consequences on learning skills.Duchenne Muscular Dystrophy (DMD) is a neurogenetic developmental disability. DMD is known mainly as a genetic disease of muscle, although it also has developmental consequences on the central nervous system. DMD is caused by a mutation of a gene on the X chromosome (Koenig et al., 1987). It occurs in about 1/3,200 boys and results in progressive muscular weakness. DMD is the most common fatal childhood inherited disorder, and affected individuals rarely live past their late -20s. NIH-PA Author ManuscriptNIH-PA Author Manuscript NIH-PA Author ManuscriptEver since its original characterization by Duchenne (1872), boys with DMD have been known to be at increased risk of mental retardation, although the majority of boys with DMD are not mentally retarded. Whether impaired cognitive function in individuals with DMD resulted from the stresses of living with a chronic, progressive, physically disabling disorder or from the underlying etiology affecting the development of the nervous system was uncertain. Yet, well before discovery of the gene that causes the disorder, decreased academic achievement scores were documented, prompting investigators to write that "an investigation of intelligence and academic achievement should be a routine part" of care for all children with DMD (Worden & Vignos, 1962).The discovery that the mutated gene in DMD codes for multiple protein products that localize to separate tissue types, including muscle and brain, offers a potential explanation for the cognitive manifestation of the DMD phenotype (for reviews see J. L. Anderson, Head, Rae, & Morley, 2002;Mehler, 2000). In the brain, dystrophin isoforms normally localize to circumscribed cerebral and cerebellar cortical regions and are absent in autopsied brains of individu...

Pancreatic glucagon and cholecystokinin octapeptide (CCK-8) were intravenously infused (1 ml/min for 10 min) alone or in combination beginning 15 min after normal-weight men had eaten a 500-ml tomato soup preload and 5 min before they were served a lunch of macaroni and beef with tomato sauce. Infusion of approximately 3 ng.kg-1.min-1 glucagon or approximately 2 ng.kg-1.min-1 CCK-8 each reduced test meal size. However, simultaneous infusion of these peptide doses reduced meal size less than the sum of the peptides' individual effects. Infusions of approximately 1.5 ng.kg-1.min-1 glucagon or approximately 1 ng.kg-1.min-1 CCK-8 had neither individual nor interactive effects on meal size. Psychophysical ratings failed to detect nonspecific side effects after any of the infusions. That exogenous glucagon and CCK-8 each reduced meal size without side effects suggests that these peptides may participate in the physiological control of human appetite; that their simultaneous infusion resulted in an infra-additive reduction in meal size suggests that they can interact antagonistically.

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Objectives: The aim of this study was to investigate executive skills in children with dystrophinopathy and to examine the association between executive functions and dystrophin gene mutation position. Methods: Fifty boys with dystrophinopathy (mean age, 11 years 0 months; ages range, 5 to 17 years) completed measures of intellectual functioning (IF), working memory and executive functioning [including Digit Span (working memory) and measures from the NIH Toolbox (selective attention/inhibitory control, set shifting, working memory, and processing speed)]. Parents completed the Behavior Rating Inventory of Executive Function (BRIEF). Mutation positions were categorized into three groups (upstream exon 30, 31–62, and downstream exon 63). Paired-samples t tests compared performance on executive measures to IF, and a one-way (three-group) multivariate analysis of covariance compared cognitive performance with mutation location controlling for motor functioning. Results: Mean performance on all executive measures was significantly lower than IF. Parents were also more likely to rate their child with dystrophinopathy as having clinically significant executive difficulties on the Shift, Emotional Control, and Behavior Regulation indices of the BRIEF. Mutation analyses resulted in small groups limiting power to detect subtle differences. Those with a downstream mutation position had significantly poorer performance on IF and Total Digit Span, but not on other measures of executive function including behavior. Conclusions: Individuals with dystrophinopathy have executive skill deficits, but they are not generally associated with more distal mutations. (JINS, 2019, 25, 146–155)