HMBS

hydroxymethylbilane synthase

3 disorders 2 causative 1 untyped 11q23.3 gene with protein product

HGNC:4982 Monarch NCBI Gene 3145 ENSG00000256269 UniProt P08397 OMIM 609806

Previous symbols: PBGD, UPS, PORC.

Normal function · from ai-gene-review (P08397, commit 79fe13b38970) · AI-generated, not KB evidence

ai-gene-review has this gene at status INITIALIZED; the description is shown only once the review is complete. Read the draft upstream.

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
Acute Intermittent Porphyria	causative germline	mechanism: HMBS deficiency in hepatocytes diagnosis: Molecular genetic testing
Porphyria-Related Leukoencephalopathy	causative germline
Inherited Porphyria	untyped Causative	mechanism: Hydroxymethylbilane Synthase Block subtype: Acute Intermittent Porphyria scoped to subtype: Acute Intermittent Porphyria

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
acute intermittent porphyria MONDO:0008294	SD	Definitive 2022-05-27	Acute Intermittent Porphyria causative Inherited Porphyria untyped

Mechanism modules · computed from kb/

heme_biosynthesis_porphyria via Acute Intermittent Porphyria, Inherited Porphyria

Identity from HGNC (snapshot 2026-10-01). Page layers are described in the gene pages documentation.