TMPRSS6 and Tangier disease: To the best of our knowledge, the prevalence of feroportin-1(-8CG), TMPRSS6 (rs855791) and HJV (I222N & G320V) gene polymorphisms in β-TM patients and the study of their possible relation to the development of iron overload was not previously studied but the effect of those genotypic variations was investigated in other conditions of altered iron metabolism.