Genetic information by age and year of HCT of the 48 patients with SAA found to have an unrecognized IBMFS. Het, heterozygous; Comp het, compound heterozygous; Hemi, hemizygous; Hom, homozygous. *One patient had dual MPL and THPO inheritance. Note: HCT sample collection began in 1989, but the first patient in this group to have HCT was in 1991.