Curated summary · agent-written · kb/genes/curated/hgnc_13886.md

All 14 claims checked against the KB draft

ABCG5 across dismech

ABCG5 (ATP binding cassette subfamily G member 5) is named by 2 disorder entries: Intrahepatic Cholestasis of Pregnancy; and Sitosterolemia.

Normal function

ai-gene-review records that ABCG5 contributes to ABC-type sterol transporter activity as one half of the ABCG5-ABCG8 heterodimer, located at the apical plasma membrane, and acting in cholesterol efflux; cholesterol homeostasis; negative regulation of intestinal cholesterol absorption; and negative regulation of intestinal phytosterol absorption.

Sitosterolemia

Sitosterolemia types ABCG5 as causative with a germline variant origin, and ClinGen rates the gene definitive for the disease. The gene sits on the node G5G8 Sterol-Efflux Transporter Deficiency, which the entry annotates with ABC-type sterol transporter activity and sterol transport, both decreased.

Other entries

Intrahepatic Cholestasis of Pregnancy records ABCG5 as a susceptibility gene.

Where the layers disagree

The KB and ai-gene-review share 0 process terms by exact identifier for ABCG5. The KB node uses the general term sterol transport, while the ABCG5 review lists cholesterol efflux and the intestinal sterol-absorption terms. The molecular function agrees: both layers use ABC-type sterol transporter activity.

Underlined values are claims re-computed from the knowledge base each time this page is built. The tables below are the source of truth.

Normal function · from ai-gene-review (Q9H222, commit 79fe13b38970) · AI-generated, not KB evidence

ABCG5 is an ATP-binding cassette half-transporter that forms an obligate heterodimer with ABCG8. The complex exports cholesterol and plant sterols across the apical membranes of hepatocytes and intestinal enterocytes, supporting biliary sterol secretion and limiting net intestinal sterol absorption. ABCG5 supplies one transmembrane domain and one nucleotide-binding domain; its Walker motifs combine with the ABCG8 signature motif at the catalytically active composite nucleotide-binding site. Assembly with ABCG8 permits maturation and export from the endoplasmic reticulum. Biallelic loss of ABCG5 causes sitosterolemia, in which defective sterol elimination produces accumulation of dietary plant sterols and cholesterol.

ABCG5 assembles with ABCG8 to export neutral sterols using ATP. Its membrane domain and nucleotide-binding domain are integral parts of the heterodimer, with the ABCG5 Walker motifs contributing to the active composite ATPase site. At hepatocyte and enterocyte apical membranes, this activity promotes biliary sterol secretion and restricts net absorption and accumulation of dietary cholesterol and plant sterols.

molecular function: protein heterodimerization activity · contributes to molecular function: ABC-type sterol transporter activity · directly involved in: cholesterol efflux; negative regulation of intestinal cholesterol absorption; negative regulation of intestinal phytosterol absorption; cholesterol homeostasis · locations: apical plasma membrane · in complex: ATP-binding cassette (ABC) transporter complex

In the knowledge base · computed from kb/ at build time

Disorders

Relationship is the entry's genetic[].relationship_type. untyped means the entry has a genetic record for the gene but does not type it; its free-text association is shown instead.

Disorder	Relationship	Where the gene appears
Intrahepatic Cholestasis of Pregnancy	susceptibility germline
Sitosterolemia	causative germline CLINGEN: definitive	mechanism: G5G8 Sterol-Efflux Transporter Deficiency

ClinGen gene–disease validity · snapshot 2026-10-03 · matched to entries by MONDO

An entry matches when ClinGen's MONDO disease is the entry's own disease term, a subtype term, or an exact-match mapping. An amber status marks an entry ClinGen supports the gene for (Definitive, Strong or Moderate) whose own record does not type it. A Limited, Disputed or Refuted tier on such an entry is not a gap.

ClinGen disease	MOI	Classification	dismech entry
sitosterolemia MONDO:0008863	AR	Definitive 2020-07-10	Sitosterolemia causative