TMPRSS6 Gene Mutations in Six Saudi Families with Iron Refractory Iron Deficiency Anemia

Iron-refractory iron deficiency anemia (IRIDA) is considered an autosomal recessive iron deficiency anemia due to mutations in the transmembrane protease serine 6 (TMPRSS6) gene. Variations in iron parameters and a higher risk of iron deficiency have been linked to the TMPRSS6 mutations. Furthermore, human genome-wide association studies (GWAS) identified a common mutation (rs855791) linked to abnormal hematological pa-rameters, highlighting the importance of the TMPRSS6 gene in the regulation of iron homeostasis. This is the first study to investigate TMPRSS6 gene mutation in six Saudi families of probands with iron deficiency anemia unresponsive to oral iron and partially responsive to parenteral iron administration. Each participant provided a vacutainer tube with three blood samples (2.5 ml each) and analyzed based on hematological, biochemical iron profiles, and followed by genotyping by PCR. The TMPRSS6 gene was amplified, sequenced, and analyzed in all probands and family members. Statistical analysis was done using SPSS and SHEsis software. Few functional mutations in these families were suggested (p.W73X, p.E523K and p.V736A). The proband of family 6 presented numerous hematological abnormalities upon initial consultation, including normocytic anemia accompanied by low Hb, normal MCV, low serum iron, low serum ferritin, and normal TIBC. While the p.W73X variant was only found in 2 families, the p.V736A variant was found in all examined Saudi families with IRIDA. Given the evi-dence outlined for these six cases, future genotype-phenotype correlation studies in a large number of IRIDA patients in Saudi Arabia may be very informative for patient management, in addition to increasing knowledge of TMPRSS6 function during development as well as factors in the regulation of TMPRSS6 and its effect on iron levels in the body.