Abstract
Objective: To report a pathogenic variant of proximal myopathy. Case details: This is a 39-year-old male patient with a previous history of muscle weakness. In 2017, he presented severe pain in the right shoulder with progressive decrease in muscle strength in the proximal part of the right upper limb, which had not been seen before. Physical examination showed muscle weakness grade 4/5 and, in the right upper limb, muscle strength grade 3/4. Atrophy was noted in the right deltoid and infraspinatus muscle. Complementary tests showed an elevated creatine phosphokinase (CPK) and creatine kinase mass (CKMB) dosage: 538ng/ml and 7.13ng/ml respectively. Electroneuromyography recorded polyphasic potentials in the right biceps and right infraspinatus muscles, others without alterations. The gene panel for myopathy evidenced a pathogenic variant in exon 12 of the philamine C gene (FLNC), not identified in the exome database. Thus, we are facing a new proximal myopathy, previously unreported. Final considerations: The heterozygous mutations of the FLNC gene are the cause of Distal Myopathy type 4 and Myofibrillar Myopathy Type 5, but the case described showed a different pattern of muscle involvement different from distal myopathy type 4 as well as from Myofibrillar Myopathy.