Frequencies of gene variant CCR5-Δ32 in 87 countries based on next-generation sequencing of 1.3 million individuals sampled from 3 national DKMS donor centers.
Level 4 - case-series / case-control
Cross-sectional observational genetic registry study
PubMed 28987960 · doi:10.1016/j.humimm.2017.10.001
What was done
Next-generation sequencing typing data for the CCR5-Δ32 variant were analyzed from 1,333,035 potential hematopoietic stem cell donors registered across three national DKMS donor centers. Allele and genotype frequencies were calculated across 87 countries of origin based on donor self-assessment.
What was found
CCR5-Δ32 allele frequencies ranged from a maximum of 16.4% in Norwegian donors to 0% in donors from Ethiopia. Homozygous CCR5-Δ32/Δ32 genotype frequency reached up to 2.3% in donors originating from the Faroe Islands. In 27 country samples, predominantly from Africa, Asia, and South America, no individuals with the homozygous CCR5-Δ32/Δ32 genotype were identified. The data confirmed an allele frequency decline from Northern to Southeastern Eurasia.
Why it matters
This large-scale dataset enables probability estimation for identifying HLA-matched, CCR5-Δ32 homozygous donors for HIV-1 curative allogeneic stem cell transplantations across diverse ancestral backgrounds.
Limits
Country of origin relied entirely on donor self-assessment. Registry participants from three DKMS centers are subject to self-selection bias and may not represent the general populations of the 87 origin countries, especially regions with small sample numbers. Clinical transplantation outcomes were not evaluated.