CP and aceruloplasminemia: Aceruloplasminemia (Acp) is a rare autosomal recessive disease (estimated prevalence 1 out of 2 × 106 in non‐consanguineous marriages in Japan) caused by mutations in the gene encoding for ceruloplasmin (Cp) that result in the absence or in an inactive form of the protein (reviewed in Kono, 2012; Miyajima, 2015a).