Encephalopathy, porphyria-related: genes and variants
Encephalopathy, porphyria-related is linked to 1 analyzed protein (HMBS). 2 DNA variants are known to cause it; 4 more are uncertain, and 0 of those already look disease-causing on computable evidence.
Last updated 2026-09-30. Research information, not medical advice.
Genes linked to Encephalopathy, porphyria-related
HMBS: Porphobilinogen deaminase
An enzyme in heme biosynthesis that joins four porphobilinogen molecules to form hydroxymethylbilane. This step is required to build the tetrapyrrole framework of heme, and HMBS dysfunction causes acute intermittent porphyria.
2 disease-causing and 4 uncertain variants in HMBS are linked to Encephalopathy, porphyria-related.
Known disease-causing variants in Encephalopathy, porphyria-related
| Variant | Position | Protein part | Clinical label |
|---|---|---|---|
| HMBS R167P | 167 | Disease-causing (★★) | |
| HMBS L81P | 81 | Disease-causing |
Same protein, different disease
- Acute intermittent porphyria is also caused by HMBS variants; they fall mostly in different places as the Encephalopathy, porphyria-related variants (21 disease-causing).
Diseases related to Encephalopathy, porphyria-related
- Acute intermittent porphyria, also linked to HMBS
- Leukoencephalopathy, porphyria-related, also linked to HMBS
Frequently asked questions
Which genes are linked to Encephalopathy, porphyria-related?
In CATVariant, Encephalopathy, porphyria-related is linked to 1 analyzed protein: HMBS (Porphobilinogen deaminase).
How many genetic variants are linked to Encephalopathy, porphyria-related?
9 variants: 2 are classified as disease-causing (pathogenic or likely pathogenic) in ClinVar and 4 are of uncertain significance or have conflicting reports.
Which uncertain variants in Encephalopathy, porphyria-related look disease-causing?
None of the uncertain variants currently reaches the likely-pathogenic range on computable evidence alone.
About this data
Variant–disease links come from ClinVar, Open Targets and UniProt, pooled from the latest public CATVariant analysis of each human protein. Evidence scores use the ACMG/AMP Bayesian points scale with computable criteria only (position among known disease variants, rarity in gnomAD, calibrated predictors, deep mutational scanning); there is no family or patient data, so they prioritise variants for expert review and never classify them.
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