<abstract xmlns="http://www.w3.org/1999/xhtml"><p> Duchenne muscular dystrophy (DMD) is the most common form of muscular dystrophy during childhood. Mutations in dystrophin (DMD) gene are also recognized as a cause of cognitive impairment. We aimed to determine the association between intelligence level and mutation location in DMD genes in Serbian patients with DMD. Forty-one male patients with DMD, aged 3 to 16 years, were recruited at the Clinic for Neurology and Psychiatry for Children and Youth in Belgrade, Serbia. All patients had defined DMD gene deletions or duplications [multiplex ligation- dependent probe amplification (MLPA), polymerase chain reaction (PCR)] and cognitive status assessment (Wechsler Intelligence Scale for Children, Brunet-Lezine scale, Vineland-Doll scale). In 37 patients with an estimated full scale intelligence quotient (FSIQ), six (16.22%) had borderline intelligence (70&lt;FSIQ ≤85), while seven (18.92%) were intellectually impaired (FSIQ &lt;70). The FSIQ was not associated with proximal and distal mutations when boundaries were set at exons 30 and 45. However, FSIQ was statistically significantly associated with mutation location when we assumed their functional consequence on dystrophin isoforms and when mutations in the 5’-untranslated region (5’UTR) of Dp140 (exons 45-50) were assigned to affect only Dp427 and Dp260. Mutations affecting Dp140 and Dp71/Dp40 have been associated with more frequent and more severe cognitive impairment. Finally, the same classification of mutations explained the greater proportion of FSIQ variability associated with cumulative loss of dystrophin isoforms. In conclusion, cumulative loss of dystrophin isoforms increases the risk of intellectual impairment in DMD and characterizing the genotype can define necessity of early cognitive interventions in DMD patients.</p></abstract>

Duchenne muscular dystrophy (DMD) is the most common form of muscular dystrophy during childhood. Mutations in dystrophin (DMD) gene are also recognized as a cause of cognitive impairment. We aimed to determine the association between intelligence level and mutation location in DMD genes in Serbian patients with DMD. Forty-one male patients with DMD, aged 3 to 16 years, were recruited at the Clinic for Neurology and Psychiatry for Children and Youth in Belgrade, Serbia. All patients had defined DMD gene deletions or duplications [multiplex ligation- dependent probe amplification (MLPA), polymerase chain reaction (PCR)] and cognitive status assessment (Wechsler Intelligence Scale for Children, Brunet-Lezine scale, Vineland-Doll scale). In 37 patients with an estimated full scale intelligence quotient (FSIQ), six (16.22%) had borderline intelligence (70<FSIQ ≤85), while seven (18.92%) were intellectually impaired (FSIQ <70). The FSIQ was not associated with proximal and distal mutations when boundaries were set at exons 30 and 45. However, FSIQ was statistically significantly associated with mutation location when we assumed their functional consequence on dystrophin isoforms and when mutations in the 5’-untranslated region (5’UTR) of Dp140 (exons 45-50) were assigned to affect only Dp427 and Dp260. Mutations affecting Dp140 and Dp71/Dp40 have been associated with more frequent and more severe cognitive impairment. Finally, the same classification of mutations explained the greater proportion of FSIQ variability associated with cumulative loss of dystrophin isoforms. In conclusion, cumulative loss of dystrophin isoforms increases the risk of intellectual impairment in DMD and characterizing the genotype can define necessity of early cognitive interventions in DMD patients.

Intellectual Ability in the Duchenne Muscular Dystrophy and Dystrophin Gene Mutation Location

Clinic for Neurology and Psychiatry for Children and Youth, Dr. Subotica 6A, 11000 Belgrade, Serbia. Tel: +381-11-265-8355. Fax: +381-11-264-5064

Faculty of Medicine, University of Belgrade, Belgrade, Serbia

Clinic for Neurology and Psychiatry for Children and Youth, Belgrade, Serbia

Center for Human Molecular Genetics, Faculty of Biology, University of Belgrade, Belgrade, Serbia

Institute of Human Genetics, Faculty of Medicine, University of Belgrade, Belgrade, Serbia

Balkan Journal of Medical Genetics

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Duchenne muscular dystrophy (DMD) is the most common form of muscular dystrophy during childhood. Mutations in dystrophin (DMD) gene are also recognized as a...

Intellectual Ability in the Duchenne Muscular Dystrophy and Dystrophin Gene Mutation Location

Published Online: Apr 10, 2015

Page range: 25 - 35

DOI: https://doi.org/10.2478/bjmg-2014-0071

© Balkan Journal of Medical Genetics

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.