IEMbase 0228: CPT1A-related Carnitine palmitoyltransferase 1A deficiency
Scope
| Field | Value |
|---|---|
| IEMbase ID | 228 |
| Nosology | 4.1.02.01 |
| Gene | CPT1A |
| External IDs | OMIM:255120 |
| Generated mapping | CANDIDATE; Carnitine_Palmitoyltransferase_II_Deficiency.yaml |
| Candidate DisMech targets | Correct target: Carnitine_Palmitoyltransferase_1A_Deficiency.yaml; reject generated CPT II candidate |
| Review date | 2026-07-07 |
IEMbase phenotype signal
IEMbase represents this as CPT1A-related carnitine palmitoyltransferase 1A deficiency, with the alternate label carnitine palmitoyl-CoA transferase 1 deficiency. The record is autosomal recessive and treatability is marked unknown.
The biochemical rows include free carnitine, long-chain acylcarnitines, C16 and C18 species, transaminases, hypoketotic hypoglycemia context, dicarboxylic organic acids, and glucose. Clinical and characteristic rows include liver dysfunction and renal tubular acidosis. Treatments listed by IEMbase are fasting avoidance and a carbohydrate-rich, long-chain-triglyceride-restricted diet, sometimes with MCT supplementation.
DisMech phenotype coverage
Carnitine_Palmitoyltransferase_1A_Deficiency.yaml is the correct target.
The local CPT1A entry covers the liver isoform of carnitine palmitoyltransferase
1, impaired outer-mitochondrial conversion of long-chain acyl-CoA to
acylcarnitine, hepatic energy failure, hypoketotic hypoglycemia,
hyperammonemia, high free carnitine with low total and long-chain
acylcarnitines, the C0/(C16+C18) diagnostic pattern, liver-focused disease,
fasting avoidance, high-carbohydrate/low-fat diet, MCT use, illness protocols,
and medication-avoidance cautions.
Concordance and completeness
Judgement: generated fuzzy candidate is a false positive; local exact CPT1A coverage exists.
The generated CPT II candidate is mechanistically wrong because CPT1A and CPT2 affect opposite sides of the carnitine shuttle and have different biochemical signatures. IEMbase and the local CPT1A entry agree on hepatic long-chain fatty-acid oxidation disease, fasting risk, hypoketotic hypoglycemia, liver dysfunction, and dietary management. The local entry is stronger for the distinctive CPT1A high-free-carnitine/low-long-chain-acylcarnitine pattern, while IEMbase adds renal tubular acidosis as a review prompt.
Curation actions
- Correct the mapping to
Carnitine_Palmitoyltransferase_1A_Deficiency.yaml. - Do not map this record to
Carnitine_Palmitoyltransferase_II_Deficiency.yaml. - Treat renal tubular acidosis as a potential phenotype-enrichment item for CPT1A if supported by primary evidence.