The Cost of Protection

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Science  07 Feb 2014:
Vol. 343, Issue 6171, pp. 580
DOI: 10.1126/science.343.6171.580-b

African Americans have a three to five times greater risk of developing end-stage kidney disease and twice the risk of dying from heart disease than do individuals of European descent. In addition to socioeconomic factors, genetic factors probably contribute to these differences. Clinical geneticists have focused on two allelic variants of APOL1 (the gene encoding apolipoprotein L1) called G1 and G2. These alleles confer protection against African sleeping sickness, which may explain why they are common in populations of African descent but rare or absent in other populations.

Two research groups independently examined the effect of the APOL1 genotype on disease burden in African Americans. Studying chronic kidney disease, Parsa et al. found that patients with two copies of G1 or G2 were twice as likely to progress to end-stage disease as those with no or one copy. Ito et al. arrived at a similar conclusion in a study of heart disease: Individuals with two copies of G1 or G2 were twice as likely to experience a major adverse cardiovascular event as those with one or no copy. In certain settings, APOL1 genotyping may help guide treatment decisions.

N. Engl. J. Med. 369, 2183 (2013); Circ. Res. 10.1161/CIRCRESAHA.114.302347 (2013).

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