Fatal infantile lactic acidosis with methylmalonic aciduria

Fatal infantile lactic acidosis with methylmalonic aciduria is an extremely rare and severe metabolic disorder that presents in the neonatal or early infantile period. This condition is characterized by the combination of profound lactic acidosis and elevated levels of methylmalonic acid in the urine, reflecting a fundamental defect in mitochondrial energy metabolism. The disorder has been associated with deficiency of mitochondrial respiratory chain complexes, particularly combined deficiencies affecting oxidative phosphorylation, and in some cases has been linked to mutations in genes involved in mitochondrial function. Affected infants typically present shortly after birth with severe metabolic acidosis, failure to thrive, hypotonia (decreased muscle tone), respiratory distress, and progressive neurological deterioration. Multisystem involvement is common, with the brain, liver, kidneys, and skeletal muscles being particularly affected. Laboratory findings include markedly elevated blood lactate levels and increased urinary excretion of methylmalonic acid. The clinical course is rapidly progressive and typically fatal in early infancy. There is currently no curative treatment for this condition. Management is primarily supportive and may include correction of metabolic acidosis with bicarbonate supplementation, nutritional support, and symptomatic care. Attempts at cofactor supplementation (such as vitamin B12 or coenzyme Q10) have generally not altered the fatal outcome. Genetic counseling is recommended for affected families. Due to the extreme rarity of this condition, knowledge is largely derived from individual case reports and small case series.

Common questions about Fatal infantile lactic acidosis with methylmalonic aciduria