[MIM 500 011, 600 462, 613 561]

Acronym for Myopathy, Lactic Acidosis, Sideroblastic Anemia

Estimated prevalence < 1 / 106. Mitochondrial cytopathy due to a mutation of gene PUS1 (12q24.33)  that codes for the pseudopurine synthase or gene YARS2 that codes for a mitochondrial tyrosyl-tRNA transferase: these mutations lead to a dysfunction of the mitochondrial tRNA. This causes a decrease in activity of complexes 1 and 4 of the respiratory chain and the presence of paracrystalline inclusions in the mitochondria.

Clinical presentation:

-        early sideroblastic anemia

-        lactic acidosis

-        digestive disorders; alimentary problems

-        later: myopathy (quickly leading to nighttime non-invasive ventilation)

-        sometimes cardiomyopathy

Anesthetic implications:

see mitochondrial cytopathies

References:

-        Shahni R, Wedatilake Y, Cleary MA, Lindley KJ, Sison KR, rahman S.
A distinct mitochondrial myopathy, lactic acidosis and sideroblastic anemia (MLASA) phenotype associates with YARS2 mutations.
Am J Med Genet  Part A 2013; 161A: 2334-8.

Updated: January 2017