ALAD
Chr 9ARaminolevulinate dehydratase
Also known as: ALADH, PBGS
The ALAD enzyme catalyzes the condensation of two molecules of delta-aminolevulinate to form porphobilinogen in the second step of heme biosynthesis, requiring zinc for activity. Biallelic mutations cause acute hepatic porphyria and increased susceptibility to lead poisoning through autosomal recessive inheritance. The gene is loss-of-function tolerant (pLI near 0), consistent with recessive disease requiring complete loss of enzyme function.
Moderate evidence — consider for supplementary testing
Population Genetics & Constraint
gnomAD v4 — loss-of-function & missense intolerance
Typical tolerance to LoF variation
Mild missense constraint
Predictions shown for reference only — model trained on dominant genes, not applicable to AR conditions.
The Badonyi & Marsh prediction model was trained exclusively on dominant disease genes. Predictions are not reliable for genes with autosomal recessive inheritance and are shown at reduced opacity for reference only.
Predictions from Badonyi M, Marsh JA. PLoS ONE. 2024;19(8):e0307312.
ClinVar Variant Classifications
0 submitted variants in ClinVar
Protein Context — Lollipop Plot
ALAD · protein map & ClinVar variants
Showing all ClinVar variants across the protein. Search a specific variant to highlight its position.
3D Protein StructureAlphaFold
External Resources
Links to major genomics databases and tools
Clinical Trials
Active and recruiting trials from ClinicalTrials.gov
No active trials found for this gene.
Search ClinicalTrials.gov →External Resources
Links to major genomics databases and tools