Distribution of Rhesus Blood Group System in the French Basques: A Reappraisal Using the Allele-Specific Primers PCR Method

Abstract

Objectives: To determine for the first time using PCR the distribution of Rhesus (Rh) blood group in French Basques and compare these results with those obtained by serology in the same sample and in the historical series from various Basque subgroups. Methods: Rh polymorphism was determined in a sample of 127 autochthonous French Basques using allele-specific primers (ASP) PCR and traditional serological technique. Statistical comparisons were performed between both techniques and with the data published from various Basque subpopulations. Results: No intra-sample discrepancies were detected between ASP-PCR and serology. A high frequency of RH Ddel exceeding 0.50, as typically described from several decades, was found here (0.511), as the peculiar frequency of cde (0.456) and cDE (0.073) haplotypes. This profile, obtained by molecular analysis, was within the range of previous historical studies in various Basque subpopulations using serological approach. The Rh polymorphism among the reviewed autochthonous Basque samples indicates a heterogeneous pattern of distribution, with individuals from the Alava province demonstrating the most atypical profile. Conclusions: Molecular biology approach using PCR confirms the peculiar pattern of Rh polymorphism which was previously defined by serology among Basques. Nevertheless, this distribution profile is not homogeneous within the Basque area.

Sequence diversity of the Rh blood group system in Basques

“…Furthermore, our analyses show that the highest frequency of the RHD deletion is found in Basques (47.2%), in agreement with other analyses [12,22]. However, the frequencies found in our Basque samples are not as extreme as shown in some previous studies, which were mainly based on antigen reactions.…”

“…However, some studies have challenged the genetic differentiation of Basques compared to other European populations [10]. One of the most striking genetic singularity of Basques is related to the Rhesus (Rh) system since they show one of the highest frequencies of the RhD negative allele in human populations [1,[11][12][13].…”

“…Since Etcheverry detected for the first time a high frequency of the RhD negative variant in Basque emigrants to Argentina [22], many studies have analyzed this variant, confirming the high frequency of the RhD negative allele using different methods and datasets [1,[11][12][13]. However, most of these studies were based on classical serologic methods and focused on the description of the antigens without describing the full genetic diversity of the system.…”

Evolutionary genetics of the human Rh blood group system

“…Yet in European populations the D-negative phenotype is observed at substantial frequencies, typically 0.15-0.17 and up to 0.29 in the Basque (Touinssi et al 2004; Urbaniak and Greiss 2000), and the frequency of the RHCE C allele is ~0.44 (Urbaniak and Greiss 2000). Similar to the effects of sickle cell and thalassemia hemoglobin heterozygosity on malarial resistance (Allen et al 1997; Allison 1954; Flint et al 1986; Kwiatkowski 2005), we asked whether these alleles confer an unknown fitness benefit whereby positive or balancing selection explains their otherwise surprisingly high frequencies (Feldman et al 1969; Westhoff 2004).…”

Is the management of Rh-Rh incompatibility with noninvasive fetal Rh genotypingfor targeted prophylaxis cost-effective in the Turkish population?

“…A high frequency of Rhnegative genotype exceeding 0.50, as typically described over several decades, is present in the Basque region of France. This rate is 15% in Caucasians, 8% in Africa, and about 1% in East Asia (13). Our higher rate could be related to migration to our region from outside and also to our hospital-based study.…”