Four new Finnish families with LGMD1D; refinement of the clinical phenotype and the linked 7q36 locus

Patients in all families had very similar phenotypes with onset of muscle weakness in the pelvic girdle muscles between the fourth and sixth decade, later involvement of the shoulder girdle, and marked walking difficulties in the eighth decade. Muscle biopsies showed myopathic and/or dystrophic features. Genotyping confirmed linkage to the same locus at chromosome 7q36 in all families by one identically segregating haplotype. The linked region was narrowed down from <6.3 to <3.4 Mb. Sequencing of the genes in the area is ongoing, aiming to identify the genetic defect.