Muscle b-enolase deficiency is a very rare inherited @entity121 caused by an enzymatic defect of distal glycolysis. So far, the condition has been described in only one @entity1 with mutations in @entity68187 in a compound heterozygous state who presented with exercise intolerance, post-exercise @entity925 and mild @entity34793 but no pigmenturia. We describe two @entity1 , one Italian and one Turkish, with consanguineous parents, who complained of several episodes of intense @entity925 , 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 b-enolase activity (20 and 10  % of residual activity, respectively). Molecular genetic analysis of @entity68187 gene revealed two novel homozygous missense mutations, ( @entity68188 and @entity68189 ). Both mutations segregated as expected in the two families. Although quite rare, muscle b-enolase deficiency should be considered in the differential diagnosis of @entity1 presenting with recurrent @entity5925 . It may present also with a more severe phenotype than previously thought.

Recurrent XXXX due to muscle b-enolase deficiency: very rare or underestimated?

@entity1 :: ('9606', 'Species') :: ['patients', 'patient', 'men'] @entity68188 :: ('p|SUB|N|151|S', 'ProteinMutation') :: ['p.Asn151Ser'] @entity34793 :: ('OMIM:123320', 'Disease') :: ['hyperCKemia'] @entity5925 :: ('MESH:D012206', 'Disease') :: ['rhabdomyolysis'] @entity68187 :: ('2027', 'Gene') :: ['ENO3'] @entity68189 :: ('p|SUB|E|187|K', 'ProteinMutation') :: ['p.Glu187Lys'] @entity925 :: ('MESH:D063806', 'Disease') :: ['myalgia'] @entity121 :: ('MESH:D009135', 'Disease') :: ['metabolic myopathy']
@entity5925 :: (MESH:D012206,Disease) :: ['rhabdomyolysis']
