The enigma of 7q36-linked autosomal dominant limb-girdle muscular dystrophy

Satu M Sandell (1) , Sanna Huovinen (2) , Jaakko Sarparanta (3) , Helena Luque (3) , Olayinka Raheem (4) , Hannu Haapasalo (2) , Peter Hackman (3) , Bjarne Udd (4)

1 Department of Neurology, Seinäjoki Central Hospital
2 Department of Pathology, Centre for Laboratory Medicine, Tampere University Hospital
3 Folkhälsan Research Center
4 Neuromuscular Research Center, Department of Neurology, University Hospital and University of Tampe

Introduction: Two families with autosomal dominant limb-girdle muscular dystrophy have been linked to a locus on chromosome 7q36 already 10 years ago. The locus has been denominated both LGMD1D and 1E, but in lack of further families to narrow down the linked region of interest this disease has remained elusive. Methods: A large Finnish family was clinically and genetically investigated. Laboratory parameters were determined including CK value, neurographic and EMG studies, cardiac and respiratory function examinations, muscle biopsies and muscle imaging by CT or MRI. Results: The patients had onset of muscle weakness in the pelvic girdle between the fourth and the sixth decade with an autosomal dominant pattern of inheritance. CK values were slightly elevated and EMG was myopathic only. Muscle biopsies showed myopathic and/or dystrophic features with very minor rimmed vacuolation and protein aggregation findings. Molecular genetic analysis indicates linkage of the disease to the locus on chromosome 7q36 completely overlapping with the previously reported locus LGMD1D/E. Discussion: Advancement towards the causative gene defect in the 7q36-linked disease needs new additional families to narrow the region of interest. The phenotype in the previously linked families has not been reported in full detail, which may be one reason for the shortage of additional families. We now report the comprehensive clinical and morphological phenotype of chromosome 7q36 linked autosomal dominant LGMD with a restricted and updated 6.4 Mb sized haplotype.

Mots clés: MUSCULAR DYSTROPHY; MYOPATHY

Satu M Sandell, Sanna Huovinen, Jaakko Sarparanta, Helena Luque, Olayinka Raheem, et al.. The enigma of 7q36-linked autosomal dominant limb-girdle muscular dystrophy. Journal of Neurology, Neurosurgery and Psychiatry, 2010, 81 (8), pp.834. ⟨10.1136/jnnp.2009.192351⟩. ⟨hal-00562295⟩