Marta Cheli
Muscle phosphorylase b kinase deficiency caused by new mutations in the PHKA1 gene.
Autori
- MARTA CHELI (DEPARTMENT OF NEUROSCIENCES, BIOMEDICINE AND MOVEMENT SCIENCES, UNIVERSITY OF VERONA, 37134 VERONA, ITALY – NEUROLOGO)
- DENISE CASSANDRINI (IRCCS FONDAZIONE STELLA MARIS, 56128 PISA, ITALY – BIOLOGO )
- DANIELE GALATOLO (IRCCS FONDAZIONE STELLA MARIS, 56128 PISA, ITALY – BIOLOGO)
- GAETANO VATTEMI (DEPARTMENT OF NEUROSCIENCES, BIOMEDICINE AND MOVEMENT SCIENCES, UNIVERSITY OF VERONA, 37134 VERONA, ITALY – NEUROLOGO)
- FILIPPO MARIA SANTORELLI (IRCCS FONDAZIONE STELLA MARIS, 56128 PISA, ITALY – NEUROLOGO)
- PAOLA TONIN (DEPARTMENT OF NEUROSCIENCES, BIOMEDICINE AND MOVEMENT SCIENCES, UNIVERSITY OF VERONA, 37134 VERONA, ITALY – NEUROLOGO)
Presentatore
MARTA CHELI
Modalità
Poster Session
Abstract
Phosphorylase b kinase deficiency (GDS IX) has been associated with different clinical phenotypes based on inheritance, age at onset and tissue involvement. The enzyme is composed of four subunits and controls glycogen breakdown. The X-linked myopathy is due to mutations in PHKA1, the gene encoding the muscle specific a subunit of phosphorylase b. The clinical presentation is characterized by exercise-induced myalgia and cramps, and weakness of exercising muscles. We report on a young man referred for exercise intolerance and proximal muscle weakness who was found to be carrier of a hemizygous deletion of three exons. The second patient, a young female with increased CK level and exercise related myalgia, turned out to be a carrier of two compound heterozygous variants. Muscle biopsy from both patients showed PAS positive subsarcolemmal vacuoles and a marked reduction of phosphorylase B kinase enzymatic activity. Our patients expand the clinical and genetic spectrum of this rare and likely under-recognized disorder