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

Abstract

AbstractBackground and ObjectivesWeak 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 MethodsWe screened forRHD*01W.42alleles 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 ofRHD*01W.42andd(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.ResultsTwo individuals harboured theRHD*01W.42/RHD*01heterozygous genotype. Assuming an allele frequency of 38.19% ford, 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.ConclusionQuébec has the highest documented prevalence of weak D type 42, which was estimated at 0.08%.