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Biology subjects

Kachala, D.

Publications and source records attributed to Kachala, D..

2 recordsLinked to original sources

Large-scale genotyping and meta-analysis of PIEZO1 short tandem repeat alleles suggest a modest association with malaria susceptibility

PIEZO1 forms a mechanosensitive ion channel involved in regulating calcium levels in red blood cells. E756del, a deletion allele within a short tandem repeat (STR) in PIEZO1, is common in many African populations and has been proposed to be associated with protection from malarial disease, but epidemiological evidence has been inconsistent. Here, we use Illumina sequencing of amplicons covering the PIEZO1 STR to genotype 5,558 severe malaria cases and 8,174 population controls from The Gambia, Kenya, and Malawi. We estimate a modest effect for E756del and meta-analysis with two published studies, for a total of 8,224 cases and 10,103 controls, reveals a consistent protective effect (OR=0.93, 95% CI 0.88-0.99). By comprehensively genotyping the STR, we identify additional, less common alleles, with two (Q745del and E756ins) showing consistent, but also modest, risk effects across studies. Although allele frequency differentiation between African and non-African populations could be consistent with a selective effect, we show that it is not exceptional compared with STR variants genome wide. Thus, our results support a protective effect of E756del against risk of malaria but with a much smaller effect size than initially reported.

genetics↗

A structural variant encoding hybrid glycophorins is associated with resistance to severe malaria

Plasmodium falciparum invades human red blood cells by a series of interactions between host and parasite surface proteins. Here we analyse whole genome sequence data from worldwide human populations, including 765 new genomes from across sub-Saharan Africa, and identify a diverse array of large copy number variants affecting the host invasion receptor genes GYPA and GYPB. We find that a nearby reported association with severe malaria is explained by a complex structural variant that involves the loss of GYPB and gain of two hybrid genes, each with a GYPB extracellular domain and GYPA intracellular domain. This variant reduces the risk of severe malaria by 40% and has recently risen in frequency in parts of Kenya. We show that the structural variant encodes the Dantu blood group antigen, and therefore a serologically distinct red cell phenotype. These findings demonstrate that structural variation of red blood cell invasion receptors is associated with natural resistance to P. falciparum malaria.

genomics↗