Haplotypes and polymorphism in the CCR5 gene in sickle cell disease

Area of Science:

• Genetics
• Hematology
• Molecular Biology

Background:

• Sickle cell disease (SCD) exhibits significant clinical heterogeneity.
• This variability is linked to HbS gene haplotypes, fetal hemoglobin levels, and environmental factors.
• The CCR5 gene polymorphism, associated with chronic inflammation, is hypothesized to impact SCD survival and inflammatory events.

Purpose of the Study:

• To identify βS and βC gene haplotypes in SCD patients.
• To investigate the prevalence of the CCR5Δ32 deletion in SCD patients.
• To explore the genetic basis of SCD heterogeneity.

Main Methods:

• DNA isolation using QIAamp DNA Investigator Kit.
• Polymerase Chain Reaction (PCR) for CCR5Δ32 detection.
• Restriction Fragment Length Polymorphism (RFLP) analysis with specific enzymes (XmnI, HindIII, HincII, HinfI) to determine β cluster haplotypes via electrophoresis.

Main Results:

• The atypical haplotype was the most prevalent (54.3%), followed by Benin (28.6%), Bantu (11.5%), Senegal (2.8%), and Cameroon (2.8%).
• No SCD patients in this cohort carried the CCR5Δ32 deletion.
• A higher frequency of atypical haplotypes was observed.

Conclusions:

• The genetic landscape of SCD patients is characterized by a high prevalence of atypical haplotypes.
• The absence of the CCR5Δ32 deletion suggests it does not play a protective role in this population.
• Observed haplotype frequencies indicate potential genetic drift and adaptation in ancestral haplotypes over time.