[Beta(o)/beta(o) thalassemia with a mild phenotype]

Area of Science:

• Genetics
• Hematology
• Molecular Biology

Background:

• Beta-thalassemia major is a severe genetic blood disorder characterized by absent beta-globin synthesis.
• The beta(o)/beta(o) genotype typically results in severe anemia requiring frequent blood transfusions.
• Clinical presentation can vary, suggesting the influence of other genetic factors.

Observation:

• A 30-year-old Algerian patient with beta(o)/beta(o) genotype presented with intermediate-severity beta-thalassemia.
• Despite the severe genotype, the patient exhibited only moderate, well-tolerated anemia.
• This mild phenotype correlated with elevated fetal hemoglobin levels.

Findings:

• The patient's mild phenotype is attributed to high fetal hemoglobin production.
• This elevation is likely due to a homozygous state for the XmnI -158 (C>T) polymorphism in the Ggamma gene promoter.
• This polymorphism influences fetal hemoglobin levels, impacting disease severity.

Implications:

• Beta-thalassemia major phenotypes can be milder than expected due to underlying genetic variations.
• Genetic polymorphisms, such as the XmnI site, are crucial modifiers of beta-thalassemia severity.
• Understanding these polymorphisms is vital for accurate diagnosis and personalized treatment strategies.