The clinical and molecular spectrum of autosomal dominant limb-girdle muscular dystrophies focusing on ransportinopathy.

Introduction: Limb-girdle muscular dystrophies (LGMD) are a clinical and genetically heterogeneous group of muscle diseases presenting with a phenotypic spectrum. Autosomal dominant LGMDs represent less than 10% of the group and are subdivided, according to the last classification, in five dominant LGMD forms (type D1-D5), in which mutations in various genes have been identified. Dominant LGMD might be due to a defect of DNAJB6 (LGMD D1), transportin-3 (LGMD D2, TNPO3-related), mutations in HNRNPDL gene (LGMD D3), in CAPN3 gene (LGMD D4) and in collagen 6 (LGMD D5, collagen 6-related). Areas covered: We present the pathomechanism of dominant LGMDs and clinical management of respiratory and bulbar complications. We analyze the clinical presentation of cases affected by LGMD D2 in a large Italo-Spanish family. We consider two main phenotypic entities: the childhood form developing the clinical features in the first decade of life and the late-onset phenotype, that present distinct clinical, histopathological and MRI features. The main features in dominant LGMDs, such as LGMD D1, D3, D4, D5 are highlighted, including the differential ones with other dystrophies. Expert opinion: Early diagnosis of LGMD, utilizing Next Generation Sequencing technique (NGS), is crucial for offering an accurate diagnosis. Muscle MRI imaging is emerging both for diagnosis and follow-up of disease progression.