P.18.2 A ten-year follow-up study on muscle strength and motor function in children, adolescents and young adults with myotonic dystrophy

Abstract

Myotonic dystrophy type 1 (DM1) is one of the more common neuromuscular disorders in childhood with strongly varying prevalence in different regions. The disorder is autosomal dominantly inherited and the genetic defect is due to a CTG trinucleotide repeat expansion localized on chromosome 19. The disorder is multisystemic with symptoms from muscles, eyes, heart, brain, gastrointestinal tract and endocrine systems. Since 1999 several projects have been carried out in a multiprofessional research group at the Sahlgrenska Academy at the University of Gothenburg, where medical problems, behavioural problems, cognitive function, muscle strength, motor function, orofacial problems and dental health in children and adolescents with DM1 have been investigated. A ten-year follow-up study was started during 2011, where today 65 children, adolescents and young adults with confirmed diagnosis have been investigated. The aim of the study was to explore how clinical features and medical consequences of the disorder change over time in children, adolescents and young adults with DM1. The results, so far, regarding changes in muscle strength and motor function are following. Muscle strength increases over time in most of the assessed patients, although the distal muscle groups in several patients show signs of deterioration. Regarding motor function there is high variability, several of the patients increase their motor function while others show a deteriorating pattern. The deterioration does not seem to be related to either age or severity of the disorder. The number of patients with foot deformities and scoliosis seem to increase over time in the group with more pronounced muscle weakness. The results are still preliminary and will be further analysed. Myotonic dystrophy type 1 (DM1) is one of the more common neuromuscular disorders in childhood with strongly varying prevalence in different regions. The disorder is autosomal dominantly inherited and the genetic defect is due to a CTG trinucleotide repeat expansion localized on chromosome 19. The disorder is multisystemic with symptoms from muscles, eyes, heart, brain, gastrointestinal tract and endocrine systems. Since 1999 several projects have been carried out in a multiprofessional research group at the Sahlgrenska Academy at the University of Gothenburg, where medical problems, behavioural problems, cognitive function, muscle strength, motor function, orofacial problems and dental health in children and adolescents with DM1 have been investigated. A ten-year follow-up study was started during 2011, where today 65 children, adolescents and young adults with confirmed diagnosis have been investigated. The aim of the study was to explore how clinical features and medical consequences of the disorder change over time in children, adolescents and young adults with DM1. The results, so far, regarding changes in muscle strength and motor function are following. Muscle strength increases over time in most of the assessed patients, although the distal muscle groups in several patients show signs of deterioration. Regarding motor function there is high variability, several of the patients increase their motor function while others show a deteriorating pattern. The deterioration does not seem to be related to either age or severity of the disorder. The number of patients with foot deformities and scoliosis seem to increase over time in the group with more pronounced muscle weakness. The results are still preliminary and will be further analysed.