Skip to content

IEMbase 0372: APOB-related apolipoprotein B deficiency

Scope

Field Value
IEMbase ID 372
Nosology 15.1.04.01
Gene APOB
External IDs OMIM:144010; OMIM:605019; ORPHA:391665
Generated mapping MAPPED; Abetalipoproteinemia.yaml
Candidate DisMech targets No exact local target; Abetalipoproteinemia.yaml is shared low-apoB context only
Review date 2026-07-07

IEMbase phenotype signal

IEMbase represents APOB-related apolipoprotein B deficiency, with alternate names familial hypobetalipoproteinemia type 1 and normotriglyceridemic hypobetalipoproteinemia. Inheritance is listed as autosomal recessive.

The cached record is clinically sparse. It lists hemolytic anemia and no clinical significance, with biochemical rows for plasma HDL cholesterol, plasma LDL cholesterol, serum triglyceride, plasma Apo B, and plasma vitamin E. Treatment contains low-fat diet.

DisMech phenotype coverage

The generated exact mapping to Abetalipoproteinemia.yaml is over-broad for a mechanism-first DisMech target. The local abetalipoproteinemia entry models MTTP-related failure of apoB-lipoprotein assembly and secretion. It has strong shared phenotype context for very low LDL-C, triglycerides, Apo B, vitamin E deficiency, fat malabsorption, and severe homozygous hypobetalipoproteinemia presentations, but its causal gene and initiating mechanism are MTTP, not APOB.

The local Familial_Hypercholesterolemia.yaml entry also mentions APOB, but in the opposite binding-defect/hypercholesterolemia direction. It is not a valid target for APOB deficiency with low LDL.

Concordance and completeness

Judgement: false positive exact mapping; APOB-related familial hypobetalipoproteinemia type 1 is a local disease gap.

IEMbase and the abetalipoproteinemia file share low apoB/LDL/triglyceride and vitamin E biology, but they diverge at the root cause: APOB deficiency versus MTTP loss of function. The IEMbase record is also much milder in clinical rows, including "no clinical significance," which should not be imported into the MTTP abetalipoproteinemia target.

Curation actions

  • Do not treat Abetalipoproteinemia.yaml as the exact target for this record.
  • Create or prioritize a separate APOB-related familial hypobetalipoproteinemia type 1 target if this condition is in DisMech scope.
  • Use Abetalipoproteinemia.yaml only as shared low-apoB/vitamin E/fat absorption context, not as the canonical mapping.
  • Review the low-fat diet and hemolytic anemia rows before importing them into any future APOB-specific entry.