title: Recurrent rhabdomyolysis due to muscle β-enolase deficiency: very rare or underestimated?
abstract: Muscle β-enolase deficiency is a very rare inherited metabolic myopathy caused by an enzymatic defect of distal glycolysis. So far, the condition has been described in only one patient with mutations in ENO3 in a compound heterozygous state who presented with exercise intolerance, post-exercise myalgia and mild hyperCKemia but no pigmenturia. We describe two men, one Italian and one Turkish, with consanguineous parents, who complained of several episodes of intense myalgia, cramps, generalized muscle tenderness and dark urine. No other family members reported similar symptoms. In both cases, there was a very mild rise in lactate during a forearm exercise test. Muscle biopsy showed minimal changes with no lipid or glycogen accumulation. Biochemical studies on muscle tissue demonstrated a marked reduction of muscle β-enolase activity (20 and 10% of residual activity, respectively). Molecular genetic analysis of ENO3 gene revealed two novel homozygous missense mutations, (p.Asn151Ser and p.Glu187Lys). Both mutations segregated as expected in the two families. Although quite rare, muscle β-enolase deficiency should be considered in the differential diagnosis of patients presenting with recurrent rhabdomyolysis. It may present also with a more severe phenotype than previously thought.
authors.affiliation: Department of Neurosciences, University of Messina, via Consolare Valeria, 98125, Messina, Italy, om471@yahoo.com.
authors.forename: Olimpia
authors.initials: O
authors.lastname: Musumeci
authors.forename: Stefen
authors.initials: S
authors.lastname: Brady
authors.forename: Carmelo
authors.initials: C
authors.lastname: Rodolico
authors.forename: Annamaria
authors.initials: A
authors.lastname: Ciranni
authors.forename: Federica
authors.initials: F
authors.lastname: Montagnese
authors.forename: M'hammed
authors.initials: M
authors.lastname: Aguennouz
authors.forename: Richard
authors.initials: R
authors.lastname: Kirk
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Allen
authors.forename: Richard
authors.initials: R
authors.lastname: Godfrey
authors.forename: Sara
authors.initials: S
authors.lastname: Romeo
authors.forename: Elaine
authors.initials: E
authors.lastname: Murphy
authors.forename: Shamima
authors.initials: S
authors.lastname: Rahman
authors.forename: Ros
authors.initials: R
authors.lastname: Quinlivan
authors.forename: Antonio
authors.initials: A
authors.lastname: Toscano
mesh_terms: D000328:Adult; D006720:Homozygote; D006801:Humans; D008297:Male; D009120:Muscle Cramp / Q000235:genetics / Q000503:physiopathology; D018482:Muscle, Skeletal / Q000473:pathology*; D020125:Mutation, Missense; D063806:Myalgia / Q000235:genetics / Q000503:physiopathology; D010751:Phosphopyruvate Hydratase / Q000235:genetics* / Q000378:metabolism*; D012206:Rhabdomyolysis / Q000175:diagnosis* / Q000235:genetics* / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology
chemical_list: D010751:Phosphopyruvate Hydratase