P.62 - Genotype-phenotype correlations in a French cohort with Becker muscular dystrophy: focus on cognitive aspects

Abstract

Becker muscular dystrophy (BMD) shares phenotypic similarities with Duchenne muscular dystrophy (DMD) because of their common genetic origin. Mutations involving Dp71 and Dp140 isoforms are known to be associated with mental retardation in DMD and BMD. The aim of our work was to study genotype- phenotype correlations in BMD patients with a particular interest to the cognitive functions. It was a bicentric, bispective, observational study in two French neuromuscular centers. Genetic, neurologic, cardiologic, respiratory data have been collected. Prospective part consisted on performing Montreal cognitive (MOCA) assessment to evaluate cognitive impairment. Statistics were performed with the R software. 54 patients were included in the retrospective study (mean age: 36 y.o; 5–63). 19 patients have been included in the prospective part. Half of patients who experienced first symptoms in adulthood were still ambulant. Non-ambulant patients have lost walking with a mean age of 38,2 years. 1/3 had cardiac involvement and 10% a respiratory failure. We did not find genotype-phenotype correlations for these features. 75% of pediatric patients had academic difficulties and the majority had adaptive schooling. For the prospective part, the average score in MOCA test was 25,1, which is lower than normal population (>26). There were no significant differences in these difficulties between patients who had mutations involving Dp71 and Dp140 mutations and the other ones. Although mutations affecting Dp71 and Dp140 are known in the literature to be associated with more prevalence of mental retardation in BMD, we could not find this association in our population. Physiopathology of cognitive impairment in dystrophinopathies is not well known. Nevertheless, we could confirm that it is a whole part of these diseases and should be evaluated and managed.