A structured approach to iron refractory iron deficiency anemia (IRIDA) diagnosis (SAID): The more is “SAID” about iron, the less it is

A case series highlighting structured hematological, biochemical and molecular approach to clinical oral iron refractoriness in children: A pressing need for a 3-tier system for classification of variants in TMPRSS6 gene

In current study, we discuss clinical oral iron refractoriness cases and highlight need for a classification system to define TMPRSS6 gene variants. Out of 231 cases of microcytic hypochromic anemia screened (Sept 2019-Dec 2020), 17 cases (7.35%) with unexplained iron refractoriness (URIDA) phenotype were enrolled after ruling out secondary causes and compliance related issues. 11 (65%) had absent/negligible response (0-0.4 g/dl Hb rise) while 6 (35%) partial (0.5-0.9 g/dl Hb rise) response to initial iron trial at 4-8 weeks. Of these 17 cases, inappropriate hepcidin levels (normal-high) were noted in 11/15 (73%) tested. TSAT/Hepcidin ratio was low in 13/15 (87%). Genetic analysis of TMPRSS6 gene by NGS revealed variations in 15/17 (88%) cases. 10/15 cases with variations harbored a common splice site INDEL that was noted to be pathogenic SNP (MAF-0.19) on case-control association study in combination with other known missense SNPs with an odds ratio of 6.38 and relative risk 2.66 (p- < 0.01).

Iron Refractory Iron Deficiency Anemia Due to 374 Base Pairs Deletion in the TMPRSS6 Gene

Iron refractory iron deficiency anemia is an autosomal recessive disorder arising from defects in iron metabolism that cause microcytic anemia to grow resistant to treatment. The patients usually do not respond to orally administered iron treatment and partially respond to intravenous iron administration. Mutations of TMPRSS6 gene which encodes matriptase-2 are the main cause of the disorder. Here, we describe the case of a 6-month-old Syrian boy who had hypochromic-microcytic anemia and normal ferritin levels at presentation. The patient did not respond to 1 month of iron therapy and his hemoglobin levels increased only after red blood cell transfusion. Mutation analysis demonstrated a novel 374 base pairs homozygote deletion spanning exon 15 of TMPRSS6 gene. Our results expand the mutation spectrum of TMPRSS6 gene in iron refractory iron deficiency anemia.