Kruppeling erythropoiesis: an unexpected broad spectrum of human red blood cell disorders due to KLF1 variants

Until recently our approach to analyzing human genetic diseases has been to accurately phenotype patients and sequence the genes known to be associated with those phenotypes; for example, in thalassemia, the globin loci are analyzed. Sequencing has become increasingly accessible, and thus a larger panel of genes can be analyzed and whole exome and/or whole genome sequencing can be used when no variants are found in the candidate genes. By using such approaches in patients with unexplained anemias, we have discovered that a broad range of hitherto unrelated human red cell disorders are caused by variants in KLF1, a master regulator of erythropoiesis, which were previously considered to be extremely rare causes of human genetic disease.