Occurrence of CCR5 Heterozygous 32 bp Deletion in Nepali Ethnic Groups

Abstract

The Chemokine (C-C) receptor 5 (CCR5) as one of the small signaling proteins, is a HIV-1 resistant gene. The major boosting to the study of CCR5 gene among ethnic groups in the world is the detection of 32 bp deletion in its heterozygous and homozygous condition which is responsible for relative or absolute resistance to HIV-1 infection. A total of 456 samples belonging to six Nepalese ethnic groups were subjected to genotyping by the use of PCR-RFLP for detecting 32 bp deletion on exon 3 of CCR5 gene. Finally, allele frequencies of 32 bp deletion among Nepalese ethnic groups were calculated by the use of Hardy-Weinberg formula for analysis and interpretation. Chidimar ethnic group, for the first time, showed heterozygous 32 bp deletion at the population level in Asia-pacific region is an excitement in which Chidimar might have conferred resistance against HIV-1 infection in Nepal.

Identification of CCR5 Δ32 Allele in Different Ethnic Groups of Nepal

“…On the contrary, in 2014, Singh reported the heterozygous CCR5 Δ32 mutation allele from 6 out of 35 Chidimar samples and 3 out of 91 Thakali samples. 4 The reason why discrepancy occurred remains to be explored in days to come.…”

“…4 X4-tropic strains of HIV-1, utilizing CXCR4 as co-receptor, arise mostly in later stages of AIDS and hence the protective effect of the homozygous deletion is not entire. 4 The defective receptor variant CCR5 Δ32 grants immunological advantage against HIV pathogenesis but possess some detrimental effects in other inflammatory diseases; such as, in case of infection with West Nile virus, where CCR5-Δ32 homozygosity is associated with a significantly higher risk for fatal outcome. 5,6 CCR5 Δ32 is predominantly found in European populations and displays a frequency decline from Northern to Southeastern Eurasia, with no or rare occurrences in Asians and native populations from Africa, the Americas and Oceania.…”