HBA1

Chr 16AD

hemoglobin subunit alpha 1

Also known as: ECYT7, HBA-T3, HBH, METHBA

NCBI Gene: 3039 ENSG00000206172 UniProt: P69905 OMIM: 141800

HBA1 encodes the alpha-1 globin chain, which combines with beta globin chains to form adult hemoglobin (HbA) responsible for oxygen transport from lungs to peripheral tissues. Mutations cause alpha thalassemias, Hemoglobin H disease, familial erythrocytosis, Heinz body anemias, and methemoglobinemia with autosomal dominant inheritance. The gene shows low constraint to loss-of-function variation (pLI 0.007, LOEUF 1.85), reflecting the presence of the nearly identical HBA2 gene that can compensate for HBA1 loss.

OMIM ResearchSummary from RefSeq, OMIM, UniProt

ADLOEUF 1.855 OMIM phenotypes

Clinical Summary— HBA1

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Gene-Disease Validity (ClinGen)

methemoglobinemia, alpha type · ADLimited

Limited evidence — not for standalone diagnostic reporting

4 total gene-disease associations curated

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Population Constraint (gnomAD)

Low constraint (pLI 0.01) — loss-of-function variants are relatively tolerated in the population.

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Clinical Trials

12 active or recruiting trials — potential therapeutic options may be available

Explore recent and relevant literature in Research Assistant →

Population Genetics & Constraint

gnomAD v4 — loss-of-function & missense intolerance

gnomAD

Tolerant — LoF & missense variants common in population

LoF Constraint

1.85LOEUF

pLI 0.007

Z-score 0.04

OE 0.98 (0.42–1.85)

Tolerant

Highly tolerant — LoF variants common in population

Missense Constraint

1.53Z-score

OE missense 0.52 (0.40–0.67)

41 obs / 79.4 exp

Tolerant

Mild missense constraint

Observed / Expected Ratios

LoF OE0.98 (0.42–1.85)

0≤0.351.4

Missense OE0.52 (0.40–0.67)

0≤0.61.4

Synonymous OE0.58

0≤1.21.6

LoF obs/exp: 3 / 3.1Missense obs/exp: 41 / 79.4Syn Z: 2.03

ClinVar Variant Classifications

0 submitted variants in ClinVar

ClinVar

Protein Context — Lollipop Plot

HBA1 · 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

Franklin by Genoox

AI-powered variant curation and clinical analysis

DECIPHER

Genomic variants and phenotypes in rare disease patients

Clinical Trials

Active and recruiting trials from ClinicalTrials.gov

ClinicalTrials.gov

ObesityDiabetes MellitusMetabolic Syndrome

The Bialystok Bariatric Surgery Study

RECRUITING

NCT04634591Medical University of BialystokStarted 2015-09-10

Bariatric surgery

Diabetic Kidney Disease

Role of Finerenone in African American Veterans With Diabetic Kidney Disease

NOT YET RECRUITING

NCT07155694Phase PHASE4Washington D.C. Veterans Affairs Medical CenterStarted 2025-09

Finerenone 10 MGEmpagliflozin 10 MG

HealthyObesity

A Study of Adipose Tissue in Adaptive Responses to Exercise

ACTIVE NOT RECRUITING

NCT06053125Phase NAMayo ClinicStarted 2023-11-09

Adipose Tissue BiopsyExercise

Type 1 Diabetes Mellitus

Establishment of Screening Pathway for High-Risk Population of Type 1 Diabetes

RECRUITING

NCT07468474Peking University First HospitalStarted 2024-09-01

Gene polymorphic detection

PancreatitisDiabetes Mellitus

Imaging Biomarkers of Pancreatic Function and Disease

ENROLLING BY INVITATION

NCT05659147Phase PHASE4Children's Hospital Medical Center, CincinnatiStarted 2023-01-18

Research MRI without administration of intravenous secretinResearch MRI with administration of intravenous secretinGenetic Sequencing

Transplant ComplicationKidney TransplantLiver Transplant

"A Privacy-protecting Environment for Child Transplants Health Related and Genomic Data Integration in the European Reference Network"

NOT YET RECRUITING

NCT07194057Instituto de Investigación Hospital Universitario La PazStarted 2025-09-30

Whole genome sequencingPolygenic Risk Score CalculationMethylome and episignatures

Adipose Tissue, BrownAdipose TissueObesity

The Physiology of Human Brown Adipose Tissue

RECRUITING

NCT04352244Beth Israel Deaconess Medical CenterStarted 2020-03-05

Fat biopsyBlood samplingBlood sample for DNA analysis

Primary MyelofibrosisPost-polycythemia Vera MyelofibrosisPost-essential Thrombocythemia Myelofibrosis

A Phase 3 Study of Pacritinib in Patients With Primary Myelofibrosis, Post Polycythemia Vera Myelofibrosis, or Post-Essential Thrombocythemia Myelofibrosis

ACTIVE NOT RECRUITING

NCT03165734Phase PHASE3Swedish Orphan BiovitrumStarted 2017-06-26

PacritinibPhysician's Choice medications

Obesity

Intensive Weight Loss Intervention Versus Usual Care for Adults With Obesity

ACTIVE NOT RECRUITING

NCT06321432Phase NACarsten DirksenStarted 2024-06-05

Intensive weight loss interventionUsual care

Type 1 Diabetes (T1D)

Circadian Mechanisms, Glucose, and CV Risks in T1D

RECRUITING

NCT06624046Phase NAUniversity of Illinois at ChicagoStarted 2025-03-13