Two new RHD alleles with deletions spanning multiple exons.

BACKGROUND: The most common large-deletion RHD allele (RHD*01N.01) includes the entire coding sequence, intervening regions and untranslated regions. The rest of large-deletion RHD alleles reported to-date consist of single-exon deletions, such as RHD*01N.67 which includes exon 1. MATERIALS AND METHODS: Samples from two donors with RhD-negative serology yielded unclear or inconclusive results when subject to confirmatory testing on RHD genotyping arrays. To determine their RHD genotypes, genomic DNA was analyzed with a combination of allele-specific PCR, long-range PCR, Sanger sequencing, and next-generation sequencing assays. RESULTS: Allele-specific PCR failed to detect products for RHD exons 1 to 3 in one sample and RHD exons 1 to 5 in the other. A quantitative next-generation sequencing assay confirmed deletion of exons 1 to 3 and 1 to 5 respectively, and detected the absence of an RHD gene in trans in both samples. Long-range PCR and Sanger sequencing enabled identification of the breakpoints for both alleles. Both deletions start within the 5' Rhesus box (upstream of the identity region for the 1-to-3 deletion, downstream of it for the 1-to-5 deletion), and end within introns. CONCLUSIONS: Resolution of unclear or inconclusive results from targeted genotyping arrays often leads to the discovery of new alleles. The 5' Rhesus box may be a hot spot for genetic recombination events, such as the large deletions described in this report.

O group is a protective factor for COVID19 in Basque population.

ABO blood groups have recently been related to COVID19 infection. In the present work, we performed this analysis using data from 412 COVID19 patients and 17796 blood donors, all of them from Gipuzkoa, a region in Northern Spain. The results obtained confirmed this relation, in addition to showing a clear importance of group O as a protective factor in COVID19 disease, with an OR = 0.59 (CI95% 0.481-0.7177, p<0.0001) while A, B and AB are risk factors. ABO blood groups are slightly differently distributed in the populations and therefore these results should be replicated in the specific areas with a proper control population.