Associations Between Self-Reported Behavioral and Learning Concerns and DMD Isoforms in Duchenne Muscular Dystrophy

Abstract

Background: Duchenne muscular dystrophy (DMD) is an X-linked recessive neuromuscular disorder resulting from loss of dystrophin. In addition to its role in muscle, isoforms of dystrophin are expressed in different cell types of the brain, and DMD has been linked to language delays, behavioral abnormalities and learning disabilities.

Objective: To determine whether disruption of specific DMD isoforms, age, corticosteroid use, ambulation status, or country are associated with behavioral and/or learning concerns in DMD.

Methods: De-identified data were collected from the Duchenne Registry from 2007-2019. Females, patients with BMD, and those without genetic testing reports were excluded from the cohort. For the genetic analysis, patients were divided into four subgroups based on the location of their mutation and the predicted isoforms affected. Bivariate analysis was conducted using chi-square for categorical variables. Two multivariate logistic regressions were used to assess independent associations with behavioral and learning concerns, respectively, and to estimate the effect size of each variable.

Results: DMD mutations disrupting expression of Dp140 and Dp71 were associated with a higher likelihood of reported behavioral and learning concerns. Corticosteroid use, categorical age, and country were other factors associated with behavior and learning concerns.

Conclusion: This data adds to our current understanding of DMD isoforms, their mutational consequence and impact on behavior and learning.

Keywords: Duchenne muscular dystrophy; behavior; epidemiology; genetics; mutation.