HAMP and IRIDA syndrome: We assessed the performance of the TSAT/hepcidin ratio to distinguish both biallelic and monoallelic affected IRIDA patients from controls with multi-causal IDA, while Heeney et al. used the TSAT/log10(hepcidin) ratio to predict the presence of biallelic pathogenic TMPRSS6 variants in patients with chronic IDA [13].