Variants of CDA have also been described, for example the dominantly inherited E325K mutation of KLF1 causing an anaemia termed CDA‐IV and X‐linked forms caused by GATA1 mutations (Nichols et al, 2000; Singleton et al, 2009; Arnaud et al, 2010). This evidence concerns the gene KLF1 and congenital dyserythropoietic anemia.