title: A case of familial dysalbuminemic hyperthyroxinemia (FDH) in Japan: FDH as a possible differential diagnosis of syndrome of inappropriate secretion of thyroid-stimulating hormone (SITSH).
abstract: Familial dysalbuminemic hyperthyroxinemia (FDH) is an autosomal dominant condition and is the most commonly inherited euthyroid hyperthyroxinemia in Caucasians. However, it is extremely rare in Asian populations. A 30-year-old Japanese woman, who was incidentally found to have apparent thyroid dysfunction, was admitted to our hospital in 2004. She had extremely elevated serum free thyroxine (FT4), moderately elevated free triiodothyronine (FT3), and normal thyroid-stimulating hormone (TSH). Clinical thyroid examination revealed no abnormalities other than small goiter. Anti-thyroglobulin antibody titer was positive, but titers of other anti-thyroid antibodies, including antithyroid peroxidase antibody, TSH receptor antibodies, and thyroid-stimulating antibody, were negative. Levels of FT3, FT4, and TSH were similar when measured by three different laboratory kits, and FT4was still high when measured by equilibrium dialysis. By affinity chromatography, FT4, TT4, and albumin were extracted to the same fraction, and the levels of FT4and TT4were extremely high. By combination of reversed phase liquid chromatography and mass spectrometry techniques, the amino acid sequence of human serum albumin was determined. The patient was found to be a heterozygote for p.R218P mutation in the gene for human serum albumin and was diagnosed as FDH. This patient, who harbored the p.R218P mutation in the albumin gene, is the fifth case report of FDH in Japan. This condition is characterized by extremely high serum FT4and moderately high serum FT3levels. Although rare, FDH should be considered in the differential diagnosis for syndrome of inappropriate secretion of TSH (SITSH) in Japan.
authors.affiliation: Department of Internal Medicine, Keio University School of Medicine, Tokyo 160-8582, Japan.
authors.forename: Sakiko
authors.initials: S
authors.lastname: Kobayashi
authors.forename: Jaeduk
authors.initials: J
authors.lastname: Yoshimura Noh
authors.forename: Taeko
authors.initials: T
authors.lastname: Shimizu
authors.forename: Tomoaki
authors.initials: T
authors.lastname: Sato
authors.forename: Isao
authors.initials: I
authors.lastname: Kurihara
authors.forename: Kiminori
authors.initials: K
authors.lastname: Sugino
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Itoh
authors.forename: Koichi
authors.initials: K
authors.lastname: Ito
mesh_terms: D000328:Adult; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D006964:Hyperpituitarism / Q000175:diagnosis*; D050010:Hyperthyroxinemia, Familial Dysalbuminemic / Q000175:diagnosis*; D007564:Japan; D013960:Thyroid Function Tests; D013972:Thyrotropin / Q000378:metabolism
chemical_list: D013972:Thyrotropin