Ribosomal protein S19 - 631 insertion is an African-originated mutation.

Ribosomes, the organelles that catalyze protein synthesis, consist of a small 40S subunit and a large 60S subunit. RPS19 gene encodes a ribosomal protein (RP) that is a component of the 40S subunit. The protein belongs to the S19E family of RPs. It is located in the cytoplasm. Mutations in this gene cause DiamondBlackfan anemia (DBA), a constitutional erythroblastopenia characterized by absent or decreased erythroid precursors in 25% of the patients. This suggests a possible extra-ribosomal function for this gene in erythropoietic differentiation and proliferation, in addition to its ribosomal function [1,2]. The RPS19 gene is located on chromosome 19q13.2 and has six exons and spans 11 kb. The first exon is untranslated, and the start codon (AUG) is located at the beginning of exon 2 [1]. RPS19 has three annotated pseudogenes. The RPS19 gene has 196 sequence variants, of which 65 had no known pathogenicity. Recent studies have provided evidence for an association between common polymorphic markers in the RPS19 exon 1 gene -631 locus insertion (ins) GCCA, AGCC and African origin [3]. At the same location, there are two common polymorphisms, -631 ins GCCA, AGCC refsnp:34020014 [4]. As previously reported, these polymorphisms do not have any effect on phenotype. The common polymorphism -631 ins GCCA was found in African-Americans with an allele frequency of 0.09 [3]. We aimed to study the frequency of this polymorphism in North African countries and also in Turkish Cypriots. In this study, 280 Egyptians, 105 Algerians, 92 Turkish Cypriots and 6 Hemoglobin (Hb) OArab cases were included. RPS19 gene exon 1 was amplified with “F5’TTA CTA CTC CCA CTT CCG GCC AGG GAA CAG 3’, R5’TCA GGC ACG CGC GCT CTG AGG CTT CGG CGT C3’ ” primers followed by digestion with the restriction enzymes HpyF10VI (MwoI, Fermentas, USA). HpyF10VI recognizes 5’-G C N N N N N^N N G C-3’. 3% agarose gel electrophoresis was used to show the fragments, which are 295bp, 158bp and 73bp for normal sample and 173bp, 158bp, 126bp, and 73bp for homozygous sample. In this study, we aimed to analyze the -631 ins GCCA mutation in three different Mediterranean populations, of which two were North African countries. Table 1 shows the genotype distribution in the three countries. Previously, the RPS19 gene -631 ins was reported as an African marker in African-Americans in the United States population [3]. In order to test this hypothesis, we analyzed individuals from two different North African countries. Although rare, we found this polymorphism in Algerians and Egyptians. Our finding supported the hypothesis. Özge Cumao ullar 1, Ay enur Öztürk1, Nejat Akar1, Solaf Elsayed2, Ezzat Elsobky2, Bakhouche Houcher3 1Pediatric Molecular Genetic Department, Ankara University, Ankara, Turkey 2Pediatric Hospital, Ain Shams University, Cairo, Egypt 3Department of Biology, University of Sétif, Faculty of Sciences, Sétif, Algeria