A rare organic acid disorder characterized by defective propionyl-CoA carboxylase (PCC) enzymes, resulting in poor catabolism of proteins and some fats, leading to toxic levels of organic acids in the blood, urine, and tissues. Caused by autosomal-recessive inherited mutations in the PCCA and PCCB genes. Symptoms typically present within the first few days of life; first presentation in childhood is possible. Findings include lethargy, poor feeding, dehydration, vomiting, hypotonia, and failure to thrive. Some patients will develop seizures, coma, hepatomegaly, cardiomyopathy, or cognitive impairment.
Laboratory findings include metabolic acidosis, hyperglycinemia, ketone bodies, ketosis, hyperammonemia, and possible thrombocytopenia and neutropenia. Long-term management includes dietary protein restriction and supplementary amino acids.