NEW YORK (Reuters Health) – A gene variant that lowers levels of white blood cells and is common in African Americans contributes to unnecessary bone-marrow biopsies, new research suggests.
“We’ve essentially created this racial health disparity by not fully considering how genetic variation affects white blood cell levels. Our study supports genotyping African Americans before performing a bone-marrow biopsy for the indication of isolated low white blood cell counts,” Dr. Jonathan Mosley, with Vanderbilt University Medical Center (VUMC), in Nashville, Tennessee, said in a news release.
As many as two-thirds of African American individuals carry the benign rs2814778-CC genotype that lowers total white blood cell (WBC) count, the Dr. Mosley and his colleagues note in JAMA Internal Medicine.
But the “normal” reference range for WBC count is based largely on averages from individuals of European ancestry and do not take into account genetic variation.
The VUMC team examined whether the rs2814778-CC genotype is associated with an increased likelihood of receiving a bone-marrow biopsy (BMB) for an isolated low WBC count.
Among 399 African American adults who had a BMB, 277 (69%) had the rs2814778-CC genotype. Thirty-five individuals (9%) had a clinical history of isolated low WBC that prompted the BMB and 34 of these individuals (97%) had the neutrophil-lowering CC genotype, compared to 67% of patients who had BMB for other clinical indications.
Among those with the CC genotype, 33 of 34 (97%) had normal BMB results performed for isolated low WBC count compared with 134 of 243 individuals (55%) with biopsies performed for other indications.
“Accounting for the rs2814778-CC genotype in clinical decision-making could avoid unnecessary BMB procedures,” Dr. Mosley and colleagues conclude in their paper.
“We hope that in the future, we can do a better job of recognizing these individuals with a benign cause for their low white blood cells counts so that bone marrow biopsies can be avoided,” VUMC study investigator Dr. Sara Van Driest said in the news release.
SOURCE: https://bit.ly/3dn0DjK JAMA Internal Medicine, online June 28, 2021.
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