P092 APOL1 genotyping: Can it aid in donor selection?

Abstract

Aim Apolipoprotein L1 (APOL1) is capable of killing Trypanosoma brucei brucei . In populations with recent African ancestry, 2 APOL1 coding variants (G1, G2) confer resistance to T. brucei rhodesiense, a leading cause of African sleeping sickness. G1 is a pair of non-synonymous single nucleotide polymorphisms (SNPs; S342G and I384M). G2 is an in-frame deletion of 2 amino acid residues, N388 and Y389. People with one G1 or G2 variant are resistant to T. b. rhodesiense , but those with 2 copies of G1 and/or G2 are at high risk for kidney disease. Knowledge of APOL1 renal-risk genotypes may aid physicians in allocation of deceased donor kidneys and suitability of living donors, potentially improving outcomes for recipients and donors. This study aimed to evaluate the feasibly of performing rapid genotyping in an “on call” situation. Methods Using a MicroAmp® Optical 96-well Reaction Plate, 2 μl of DNA is added to 3 wells. A cocktail containing TaqMan® Genotyping Master Mix plus Custom TaqMan® SNP Genotyping Mix is made for each of the 3 SNP’s (rs73885319 [G1a], rs60910145 [G1b], rs143830837 [G2]) then added to the appropriate wells. The tray is sealed, placed into a Thermo-Fisher ViiA7 TM and run using a predefined program. Based on intensity data, risk is assigned based on the homozygous presence of the nucleotide guanine at both of the sites in G1 or homozygosity of deletion at G2. Alternatively, risk can be assigned via the combination of heterozygous mutations at both G1 and G2. Results To date, nearly 100 African American deceased donors and 10 potential living donors have been tested. Utilizing Real-time PCR techniques, it was feasible to perform APOL1 testing in an afterhours situation, adding no more than 30 min to the time required for HLA typing. Conclusions APOL1 genotyping may assist in determining risk for chronic kidney disease. We conclude that rapid APOL1 testing is feasible to perform alongside our normal histocompatibility testing, even in on call situations. B.I. Freeman: Grant/Research Support; Company/Organization; Novartis Pharmaceuticals. Consultant; Company/Organization; Ionis Pharmaceuticals. Other (Identify); Company/Organization; Wake Forest University Health Sciences and Dr. Barry Freedman have applied for a patent related to APOL1 genetic testing.