There are two X-linked sideroblastic anemias (XLSAs), one caused by mutations of an erythroid-specific form of the heme biosynthetic enzyme aminolevulinic acid-synthase (ALAS2) [6], and one caused by mutation of a mitochondria-localized transport protein, ATP-binding cassette, member b7 (ABCb7) [7]—that plays a role in maturation/transport of iron-sulfur cluster containing proteins. Here, ABCB7 is linked to X-linked sideroblastic anemia 1.