FDH is inherited in an autosomal dominant manner and is characterized by enhanced binding of thyroxine to a mutant form of albumin, probably at Site 1, subdomain 11A.
FDH was associated with the albumin SacI(+)/Gc 1S haplotype, yielding a LOD (logarithm of the odds ratio) score of 5.53, with a recombination frequency of 0.