title: Successful every-other-day liothyronine therapy for severe resistance to thyroid hormone beta with a novel THRB mutation; case report.
abstract: BACKGROUND
  Resistance to thyroid hormone beta (RTHβ) is a rare and usually dominantly inherited syndrome caused by mutations of the thyroid hormone receptor β gene (THRB). In severe cases, it is rarely challenging to control manifestations using daily therapeutic replacement of thyroid hormone.
  
  
  METHODS
  The present case study concerns an 8-year-old Japanese girl with a severe phenotype of RTH (TSH, fT3, and fT4 were 34.0 mU/L, >25.0 pg/mL and, >8.0 ng/dL, respectively), caused by a novel heterozygous frameshift mutation in exon 10 of the thyroid hormone receptor beta gene (THRB), c.1347-1357 del actcttccccc : p.E449DfsX11. RTH was detected at the neonatal screening program. At 4 years of age, the patient continued to suffer from mental retardation, hyperactivity, insomnia, and reduced resting energy expenditure (REE), despite daily thyroxine (L-T4) therapy. Every-other-day high-dose liothyronine (L-T3) therapy improved her symptoms and increased her REE, without thyrotoxicosis.
  
  
  CONCLUSIONS
  In a case of severe RTH, every-other-day L-T3 administration enhanced REE and psychomotor development, without promoting symptoms of thyrotoxicosis. Every-other-day L-T3 administration may be an effective strategy for the treatment of severe RTH.
authors.affiliation: Department of Pediatrics, Shiga University of Medical Science, Tsukinowa, Seta, Otsu, 520-2192, Japan. maruo@belle.shiga-med.ac.jp.
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Maruo
authors.affiliation: Department of Pediatrics, Shiga University of Medical Science, Tsukinowa, Seta, Otsu, 520-2192, Japan. asamim@belle.shiga-med.ac.jp.
authors.forename: Asami
authors.initials: A
authors.lastname: Mori
authors.affiliation: Department of Pediatrics, Shiga University of Medical Science, Tsukinowa, Seta, Otsu, 520-2192, Japan. yori708@belle.shiga-med.ac.jp.
authors.forename: Yoriko
authors.initials: Y
authors.lastname: Morioka
authors.affiliation: Department of Pediatrics, Shiga University of Medical Science, Tsukinowa, Seta, Otsu, 520-2192, Japan. csawai@belle.shiga-med.ac.jp.
authors.forename: Chihiro
authors.initials: C
authors.lastname: Sawai
authors.affiliation: Department of Pediatrics, Shiga University of Medical Science, Tsukinowa, Seta, Otsu, 520-2192, Japan. osawa@belle.shiga-med.ac.jp.
authors.forename: Yu
authors.initials: Y
authors.lastname: Mimura
authors.affiliation: Department of Pediatrics, Shiga University of Medical Science, Tsukinowa, Seta, Otsu, 520-2192, Japan. matsui@belle.shiga-med.ac.jp.
authors.forename: Katsuyuki
authors.initials: K
authors.lastname: Matui
authors.affiliation: Department of Pediatrics, Shiga University of Medical Science, Tsukinowa, Seta, Otsu, 520-2192, Japan. takeuchi@belle.shiga-med.ac.jp.
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Takeuchi
mesh_terms: D001483:Base Sequence; D002648:Child; D003409:Congenital Hypothyroidism / Q000235:genetics; D004252:DNA Mutational Analysis; D005260:Female; D020249:Hormone Replacement Therapy; D006801:Humans; D008969:Molecular Sequence Data; D009154:Mutation; D012720:Severity of Illness Index; D037042:Thyroid Hormone Receptors beta / Q000235:genetics*; D018382:Thyroid Hormone Resistance Syndrome / Q000188:drug therapy* / Q000235:genetics*; D016896:Treatment Outcome; D014284:Triiodothyronine / Q000627:therapeutic use*
chemical_list: D037042:Thyroid Hormone Receptors beta; D014284:Triiodothyronine