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10 sources retrieved Β· Most recent: April 2026 Β· Index updated 14 days ago
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HAL
histidine ammonia-lyase
Chromosome 12 Β· 12q23.1
NCBI Gene: 3034Ensembl: ENSG00000084110.12HGNC: HGNC:4806UniProt: P42357
42PubMed Papers
21Diseases
0Drugs
1Pathogenic Variants
CLINICAL
OMIM Disease Gene
DATA QUALITY
βœ“ Experimental GO Evidenceβœ“ Swiss-Prot Reviewed
histidine ammonia-lyase activityprotein bindingL-histidine catabolic processcytosolhistidinemiaskin neoplasmcutaneous melanomaskin disease
✦AI Summary

HAL (histidine ammonia-lyase) is a cytosolic enzyme that catalyzes the nonoxidative deamination of histidine to urocanic acid, representing a critical step in histidine catabolism 1. The HAL gene is a single-copy gene spanning approximately 25 kb with 21 exons located on chromosome 12, with transcription regulated by hepatic and epidermis-specific transcription factors including C/EBP, NFIL6, and HNF5 1. HAL deficiency causes histidinemia, an inborn metabolic error characterized by reduced histidase activity and accumulation of histidine and urocanic acid 1. This condition represents the most frequent inborn metabolic error in Japan 1. The molecular characterization of the HAL gene has facilitated investigation of both symptomatic and asymptomatic forms of histidinemia, with identified polymorphisms in exon 16 enabling genetic screening 1. Understanding HAL function and mutations is essential for diagnosing and potentially developing therapeutic strategies for histidinemia, though specific clinical manifestations and long-term management approaches require further investigation beyond the currently available literature.

Sources cited
1
HAL catalyzes nonoxidative deamination of histidine to urocanic acid; gene structure spans 25 kb with 21 exons; histidinemia results from reduced histidase activity; most frequent inborn metabolic error in Japan; transcription regulated by C/EBP, NFIL6, HNF5 and other factors; polymorphism identified in exon 16
PMID: 8530107
⚠Limited data available β€” This gene has 1 indexed publication. Summary and analysis may be incomplete.
Disease Associationsβ“˜21
histidinemiaOpen Targets
0.69Moderate
skin neoplasmOpen Targets
0.40Moderate
cutaneous melanomaOpen Targets
0.37Weak
skin diseaseOpen Targets
0.37Weak
basal cell carcinomaOpen Targets
0.37Weak
skin cancerOpen Targets
0.37Weak
neurodegenerative diseaseOpen Targets
0.30Weak
COVID-19Open Targets
0.30Weak
vitamin D deficiencyOpen Targets
0.30Weak
seborrheic keratosisOpen Targets
0.29Weak
actinic keratosisOpen Targets
0.29Weak
keratinocyte carcinomaOpen Targets
0.29Weak
sunburnOpen Targets
0.29Weak
hepatocellular carcinomaOpen Targets
0.09Suggestive
neoplasmOpen Targets
0.08Suggestive
cholangiocarcinomaOpen Targets
0.07Suggestive
iminoglycinuriaOpen Targets
0.07Suggestive
beta-aminoisobutyric acid, urinary excretion ofOpen Targets
0.07Suggestive
cystathioninuriaOpen Targets
0.07Suggestive
phosphohydroxylysinuriaOpen Targets
0.07Suggestive
HistidinemiaUniProt
Pathogenic Variants1
NM_002108.4(HAL):c.1520-5_1538delLikely pathogenic
Histidinemia
β˜…β˜†β˜†β˜†2023
View on ClinVar β†—
Related Genes
CNDP2Protein interaction94%CNDP1Protein interaction92%ARG1Protein interaction89%FTCDProtein interaction88%GDAProtein interaction85%UROC1Protein interaction81%
Tissue Expression6 tissues
Liver
100%
Bone Marrow
4%
Lung
2%
Ovary
0%
Heart
0%
Brain
0%
Gene Interaction Network
Click a node to explore
HALCNDP2CNDP1ARG1FTCDGDAUROC1
PROTEIN STRUCTURE
Preparing viewer…
AlphaFoldAI-predicted Β· UniProt P42357
View on AlphaFold β†—
Constraintβ“˜
LOEUFβ“˜
1.21LoF Tolerant
pLIβ“˜
0.00Tolerant
Observed/Expected LoF0.97 [0.78–1.21]
RankingsWhere HAL stands among ~20K protein-coding genes
  • #9,883of 20,598
    Most Researched42
  • #5,151of 5,498
    Most Pathogenic Variants1
  • #12,758of 17,882
    Most Constrained (LOEUF)1.21
Genes detectedHAL
Sources retrieved10 papers
Response timeβ€”
πŸ“„ Sources
10β–Ό
1
Spectacle Lenses With Aspherical Lenslets for Myopia Control vs Single-Vision Spectacle Lenses: A Randomized Clinical Trial.
PMID: 35357402
JAMA Ophthalmol Β· 2022
1.00
2
Myopia Control Efficacy of Spectacle Lenses With Aspherical Lenslets: Results of a 3-Year Follow-Up Study.
PMID: 37040846
Am J Ophthalmol Β· 2023
0.90
3
Comparison of the performance of myopia control in European children and adolescents with defocus incorporated multiple segments (DIMS) and highly aspherical lenslets (HAL) spectacles.
PMID: 39741002
BMJ Paediatr Open Β· 2024
0.80
4
The Peripheral Defocus Designed Spectacle Lenses Might Increase Astigmatism in Myopic Children.
PMID: 40067288
Transl Vis Sci Technol Β· 2025
0.70
5
Spectacle Lenses With Highly Aspherical Lenslets for Slowing Axial Elongation and Refractive Change in Low-Hyperopic Chinese Children: A Randomized Controlled Trial.
PMID: 39197509
Am J Ophthalmol Β· 2025
0.60