Intellectual disability and neurobehavioural comorbidities affect at least 50% of the individuals with Duchenne muscular dystrophy (DMD), which, although a rare genetic disease, is the most common form of muscular dystrophy in childhood. Several studies have documented that 25% of the DMD population has intellectual disability with recent studies suggesting that autism and clinically relevant hyperactivity affects 20% and 25% of DMD boys respectively. A milder allelic variant, named Becker muscular dystrophy (BMD), has similar prevalence in the population and is also associated with variable degrees of central nervous system (CNS) comorbidities, which however have been less well defined.
We will address this knowledge gap in a large multicentre study funded by the European Commission (EU H2020) involving 6 countries (Denmark; The Netherlands; France; Spain; Italy and UK) with the largest European neuromuscular centres and advocacy groups. The aim will be to study the neurobehavioural aspects of DMD and BMD as well as their correlation to the genotype.
This study will involve male participants with DMD aged 5-17 years and with BMD aged 5-50 years, who will complete a battery of cognitive and behavioural assessments. The objective of this study is to deep phenotype a cohort of 270 individuals with DMD and BMD, focussing on the cognitive and neurobehavioural aspects of these conditions. A sub-groups of patients will also undergo magnetic resonance imaging (MRI) to investigate brain structure, volumetric features, perfusion, functional connectivity and metabolism. This information will then be correlated to the location of the underlying DMD gene mutation. The brain imaging part is also going to involve age and sex-matched controls.
While there have been major improvement on the definition of the genetic basis of the skeletal aspects of dystrophinopathies and their correlation to the DMD genotype, our knowledge on the spectrum of lifespan CNS comorbidities and the precise genotype / phenotype correlations in patients with different DMD mutations is still limited. A study looking into the association between different dystrophin isoforms and different CNS manifestations would therefore offer a unique opportunity to unravel the role of specific dystrophin isoforms and the associated circuitries in brain function.