Organic acidemias

Question 1

What are some general features of organic acidemias?

Answer 1

Metabolic acidosis with raised anion gap

May have high ammonia + lactate

Question 2

What are 3 most common organic acidemias?

Answer 2

Propionic acidaemia
Methylmalonic acidemia
Isovaleric acidemia

Question 3

What is propionic acidemia?

Answer 3

Defect in propionyl-CoA carboxylase (needed to convert propionyl-CoA to methylmalonyl-CoA
AR

Question 4

What are clinical features of propionic acidemia?

Answer 4

Normal physical appearance
Progressive encephalopathy since newborn period
Vomiting
Neutropenia/thrombocytopenia
Late complications - pancreatitis, cardiomyopathy, tubular +glomerular dysfunction, hyperammonia, basal ganglia stroke.

Question 5

What is the treatment for propionic acidemia?

Answer 5

Low protein diet
Biotin supplement
L-Carnitine supplement

Question 6

What is the genetic defect in methylmalonic aciduria?

Answer 6

Defect in methylmalonyl CoA mutase (converts MM-CoA into succinyl CoA)
AR

Question 7

How do kids with MMA present?

Answer 7

FTT +/- hepatomegaly
Progressive encephalopathy
Vomiting
High ammonia
Nutritional Vit B12 deficiency also presents like MMA