Proceedings of the XIII Congress of mediterranean society ofMyology

摘要

Objective. To diagnose metabolic myopathies mimicking LGMD it is useful to perform in hyperckemias or LGMD of unknown cause a dried blood spot (DBS) screening or NGS (next generation screening).Method. Metabolic myopathies are muscle disorders were an enzyme defect may cause a metabolic block with glycogen or lipid accumulation. These muscle disorders might mimic LGMD since they present often a proximal symmetric muscle involvement:adult acid maltase deficiency (AMD) has been named LGMD 2V, now a revised classification has been proposed on the basis of histopathology, MRI changes, clinical criteria and elevated CK. The use of next generation screening (NGS) has allowed to reach a diagnosis as well as organic acid and acyl-carnitine profile tests by GC/MS.Results. AMD pertains to metabolic myopathies and presents a wide spectrum of muscle involvement, spanning severe forms, with infantile onset and cardiomyopathy to relatively benign forms, denominated late-onset Pompe disease (LOPD) where cardiomyopathy is found only in about 10% of cases but respiratory involvement is frequent. AMD is relatively uncommon but important to diagnose disorder, since LOPD patients respond to ERT variably according to age at onset of symptoms in the spectrum from earlychildhood to late adulthood. The response of muscle weakness is variableamong individuals with the classic infantile Pompe where consists inreversal of cardiomyopathy, increased survival, in adult LOPD cases usually6MWT and GSGC scale are used to monitor outcome. A proximal myopathicpresentation can be found also in primary or secondary muscle carnitinedeficiency found in riboflavin responsive Lipid Storage Myopathies (RR-MADD)due to ETF-dehydrogenase deficiency.Conclusions. It is important to reach in metabolic cases adefinite diagnosis since such myopathies can be treated: AMD respondsvariably to ERT for 2-4 years and RR-MADD to carnitine/riboflavinsupplementation. In undefined LGMD cases a diagnosis can be nowdays reachedby NGS.