Prevalence of weak D phenotypes in the general population of Québec, Canada: A focus on weak D type 42

• Published in: Vox sanguinis 2023-07, Vol.118 (7), p.577-581
• Main Authors: Drouin, Mathieu, Rochette, Samuel, St‐Louis, Maryse, Lewin, Antoine, Laganière, Josée
• Format: Article
• Language: English
• Subjects: Alleles; Blood Group Antigens; Canada; Estimates; Gene frequency; genetics; Genotype; Genotypes; genotyping; Humans; Mathematical analysis; Phenotype; Phenotypes; Prevalence; Quebec - epidemiology; RBC antigens and antibodies; Rh-Hr Blood-Group System - genetics
• ISSN: 0042-9007; 1423-0410
• DOI: 10.1111/vox.13447

Background and Objectives Weak D type 42 accounts for an unusually high proportion of weak D phenotypes in Québec (Canada), which contrasts with other predominantly White populations. However, its prevalence in the general population is unknown. We estimated the prevalence of weak D type 42 and other common weak D phenotypes in Québec. Materials and Methods We screened for RHD*01W.42 alleles among 1000 individuals of CARTaGENE—a cohort representative of Québec's population. The prevalence of weak D type 42 was calculated based on the allele frequency of RHD*01W.42 and d (i.e., all recessive alleles that confer a D− phenotype), assuming a Hardy–Weinberg equilibrium. This prevalence was then leveraged to calculate that of other common weak D phenotypes, using published prevalence estimates among weak D phenotypes. Results Two individuals harboured the RHD*01W.42/RHD*01 heterozygous genotype. Assuming an allele frequency of 38.19% for d, the overall prevalence of weak D type 42 was 0.08%. The following prevalence estimates were also obtained: 0.44% for all weak D phenotypes and 0.07%, 0.01% and 0.04% for weak D types 1, 2 and 3, respectively. Conclusion Québec has the highest documented prevalence of weak D type 42, which was estimated at 0.08%.