Iron overload is a major cause of morbidity in β-thalassemia major attributed to multiple transfusions and inadequate chelation [1]. Genetic variants in iron regulating genes such as HFE, HAMP, and SLC40A1 have been identified as genetic modifiers of iron overload in thalassaemic patients [2–5]. Elucidating the role of genetic variants may explain heterogeneity of iron overload in β-thalassemia patients. In this prospective study, we measured serum ferritin, hepcidin and screened genetic variants thatmight influence iron status. Patients with β-thalassemia (age ≤15 years) based on clinical and molecularfindingswere included in this study. This studywas approved byour institutional review board. Informedwritten consentwas obtained from all patients enrolled in this study. Serum hepcidin was measured by ELISA (DRG, GmbH, Germany). Genetic variants TMPRSS6 c.2207A N G (rs855791 G N A), TFR2 c.714 C N G (rs34242818 C N G), HFE 845 G N A (rs1800562) and HFE c.187C N G (rs1799945 C N G) were screened by restriction fragment length polymorphism (RFLP). Variable number of tandem repeats (VNTRs) in TMPRSS6 c.18426_1842-2 del CACCC (rs200434923) and SLC40A1 c.-102-209_102206 in. CGG (rs371896375) were screened using genetic analyser (ABI 3130). Three SNPs in TF gene rs3811647, rs1799899 and rs1799852 [c.1330 + 278G N A, c.829.G N A, c.358 C N T respectively] and one SNP in TMPRSS6 gene rs4820268 [c.1536 C N T] were screened by high resolution melting assay (HRM). Statistical analysis was carried out using the software SPSS, version 20. One hundred and thirty patients (n = 130) with β-thalassemia major were included in the study. One hundred and two patients were receiving chelation. Patients' characteristics and other relevant details are given in Table 1. Further biochemical andmolecular analyses were carried out in ninety onepatients (n=91)where all the parameters were available. Serum hepcidin was significantly higher in patients [median—26.3 (7.12–85.8) ng/ml] as compared to healthy controls [14.6 (4.82–53.6) ng/ml]; however very low hepcidin/ferritin ratio was observed in patients (Fig. 1). Serum hepcidin was significantly induced in patients but low hepcidin to ferritin ratio indicates inappropriate induction of hepcidin with respect to their iron status. As expected age and number of transfusions were positively correlated with ferritin (r= 0.343 p= 0.000 & r = 0.329 p= 0.002 respectively). Interestingly, patients with β mutations had significantly elevated ferritin compared to other two groups (p = 0.04); although the type of mutation did not correlate with number of transfusions (βvs β median transfusion 100 vs 97.5; p = 0.2). This is consistent with the fact that severity of ineffective erythropoiesis is a strong modifier of iron absorption. Quartile analysis of transfusions with ferritin demonstrated twenty three patients with discordant ferritin levels. rs371896375 (SLC40A1)

There is emerging evidence that there are genetic modifiers of iron indices for HFE gene mutation carriers at risk of hereditary hemochromatosis. A random sample, stratified by HFE genotype, of 863 from a cohort of 31 192 people of northern European descent provided blood samples for genotyping of 476 single nucleotide polymorphisms (SNPs) in 44 genes involved in iron metabolism. Single SNP association testing, using linear regression models adjusted for sex, menopause and HFE genotype, was conducted for four continuously distributed outcomes: serum ferritin (log transformed), transferrin saturation, serum transferrin, and serum iron. The SNP rs884409 in CYBRD1 is a novel modifier specific to HFE C282Y homozygotes. Median unadjusted serum ferritin concentration decreased from 1194 microg/l (N = 27) to 387 microg/l (N = 16) for male C282Y homozygotes and from 357 microg/l (N = 42) to 69 microg/l (N = 12) for females, comparing those with no copies to those with one copy of rs884409. Functional testing of this CYBRD1 promoter polymorphism using a heterologous expression assay resulted in a 30% decrease in basal promoter activity relative to the common genotype (P = 0.004). This putative genetic modifier of iron overload expression accounts for 11% (95% CI 0.4%, 22.6%) of the variance in serum ferritin levels of C282Y homozygotes.