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Genetic Archaeology
GENETIC ARCHAEOLOGY // PROFILE

HBB

Hemoglobin Subunit Beta

CHR 11

Overview

The HBB gene encodes the beta chain of hemoglobin, the protein in red blood cells responsible for transporting oxygen throughout the body. Mutations in this gene are the cause of some of the most common hereditary diseases worldwide.

📍 Chromosomal Position

11p15.4 (Chromosome 11)

🧬 Gene Category

Hereditary Diseases

🔬 Inheritance

Autosomal recessive

📊 Prevalence

Variable (up to 1:50 in high-risk areas)

Function & Significance

The HBB gene provides the instructions for building the beta-globin protein. Two beta-globin proteins combine with two alpha-globin proteins to form a hemoglobin A (HbA) complex.

Hemoglobin binds oxygen in the lungs and releases it in the tissues. Without functional HBB, the oxygen supply to the body can be massively impaired.

🚀 Gene Therapy Breakthrough

HBB is the first gene for which CRISPR gene therapies (Casgevy®, Lyfgenia®) were approved in 2023 to cure sickle cell anemia.

Associated Diseases

Mutations in the HBB gene lead to so-called hemoglobinopathies:

  • 🩸 Sickle Cell Anemia (HbS)

    Point mutation leads to deformed erythrocytes and vascular occlusions.

  • 🩸 Beta-Thalassemia

    Decreased production of beta-globin leads to severe anemia.

  • 🩸 Hemoglobin C & E Diseases

    Variants that often occur in combination with HbS or thalassemia.

🧬 Relevant SNPs

Clinically significant variants in the HBB gene:

rs334
11:5227002
Allele 1

A

/

Allele 2

T

Significance: HbS (Sickle cell mutation). Carriers (AT) have malaria protection; homozygous carriers (TT) develop sickle cell anemia.

rs713040
11:5225464
Allele 1

G

/

Allele 2

A

Significance: IVS1-110 splice mutation. One of the most common causes of beta-thalassemia in the Mediterranean region.

⚕️ Clinical Management

Treatment includes blood transfusions, hydroxyurea, or, if eligible, the new gene therapies. Newborn screening is standard in many countries.

📚 Data Sources

  • OMIM: #141900 – Hemoglobin Subunit Beta
  • dbSNP: rs334, rs713040 – SNP Database (NCBI)
  • PubMed: HBB Gene Therapy Trials (2023/24)

Biological Function

Beta-globin is one of the two protein components of adult hemoglobin (HbA). Mutations impair the oxygen transport capacity of red blood cells.

Associated Conditions

Sickle Cell Disease Beta-Thalassemia Major Beta-Thalassemia Minor HbE Disease
Molecular Analysis

Analyzed Markers

ID Unknown Pathogenic
Pos: chr11:5227002 | Alleles: -/-

HbS (Glu6Val) - Pathogenic for Sickle Cell Anemia. Homozygous: severe anemia, pain crises. Heterozygous: Malaria protection.

ID Unknown Pathogenic
Pos: chr11:5225464 | Alleles: -/-

IVS1-110 G>A - Pathogenic for Beta-Thalassemia. Most common mutation in the Mediterranean region.