Methylmalonic acidemia varies in symptom presentation depending on whether it is early or late onset, with neurologic symptoms always predominating.
Methylmalonic acidemia is an autosomal recessive disorder caused by defects in the methylmalonyl coenzyme A mutase or in the metabolism of its coenzyme cobalamin.
Early-onset forms of methylmalonic acidemia usually start within 1 year of age, and the most serious neurological symptoms are brain damage, mostly involving bilateral pallidum, convulsions, motor dysfunction, and choreoathetosis, and are often accompanied by hematologic damage, such as megaloblastic anemia, and in some cases, hepatic and renal impairment.
Methylmalonic acidemia late-onset mostly appears at the age of 4 to 14 years old, some develop in adulthood, often combined with spinal cord, peripheral nerves, liver, kidneys, eyes, blood vessels and skin and other multi-system damage, manifested as acute neurological symptoms, such as cognitive decline, blurred consciousness, and intellectual backwardness, and in severe cases, subacute spinal cord degeneration occurs.
If the above symptoms occur, it is recommended to go to the pediatrician in time.