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Hyperglycinemia and propionyl coA carboxylase deficiency and episodic severe illness without consistent ketosis
Insights
Propionyl CoA carboxylase deficiency, a cause of ketotic hyperglycinemia syndrome, was identified in an infant. This condition presented with severe metabolic crises, even without consistent ketonuria, highlighting diagnostic challenges.
Area of Science:
- Biochemistry
- Genetics
- Pediatric Medicine
Background:
- Propionyl CoA carboxylase (PCC) deficiency is an inborn error of metabolism.
- It is a cause of the ketotic hyperglycinemia syndrome, characterized by propionic acidemia and hyperglycinemia.
- Diagnosis can be challenging due to variable clinical presentations.
Observation:
- A 7-month-old boy presented with failure to thrive, vomiting, anorexia, weight loss, weakness, hypotonia, and generalized seizures.
- He exhibited propionic acidemia and hyperglycinemia.
- Notably, ketonuria was inconsistent, and ketones were absent during severe metabolic crises.
Findings:
- Propionyl CoA carboxylase deficiency was confirmed as the underlying cause.
- Large amounts of pyrrolidone carboxylic acid were detected in body fluids.
- The patient experienced fatal metabolic decompensation despite the absence of significant ketonuria.
Implications:
- This case underscores the importance of considering PCC deficiency in infants with unexplained metabolic acidosis and neurological symptoms.
- The absence of consistent ketonuria highlights the need for broader metabolic investigations beyond routine ketone testing.
- Identifying elevated pyrrolidone carboxylic acid may offer an additional diagnostic clue for PCC deficiency.
Abstract:
Propionyl CoA carboxylase deficiency was found in a 7-month-old boy who presented with attacks of vomiting, anorexia, weight loss, weakness, and hypotonia. He failed to thrive and had generalized seizures. He had propionic acidemia and hyperglycinemia; these are the manifestations of the ketotic hyperglycinemia syndrome. However, ketonuria was not a consistent part of his clinical picture, and he had at least two episodes of acute overwhelming illness, the latter one fatal, in which ketones were never found in the urine. Large amounts of pyrrolidone carboxylic acid were found in body fluids.