title: A Japanese Family with Central Hypothyroidism Caused by a Novel IGSF1 Mutation.
abstract: Hemizygous mutations in the immunoglobulin superfamily member 1 (IGSF1) gene have been demonstrated to cause congenital central hypothyroidism in males. This study reports a family with a novel mutation in the IGSF1 gene located on the long arm of the X chromosome.
  
  
  
  A two-month-old boy was diagnosed with central hypothyroidism because of prolonged jaundice. A thyrotropin-releasing hormone (TRH) stimulation test indicated dysfunction in both the hypothalamus and the pituitary gland, and prompted the IGSF1 gene to be analyzed. The patient had a novel nonsense variant, c.2713C>T (p.Q905X), in exon 14 of the IGSF1 gene. Studies of the family revealed that the patient's sister and mother were heterozygous carriers of the IGSF1 mutation. The patient's maternal uncle carried the same mutation as the proband but had no overt symptoms. The mother and uncle started levothyroxine supplementation because of subclinical hypothyroidism.
  
  
  
  A novel mutation (c.2713C>T, p.Q905X) of the IGSF1 gene was identified that causes congenital central hypothyroidism in a Japanese family. The findings further expand the clinical heterogeneity of this entity.
authors.affiliation: 1 Department of Pediatrics, Osaka City University Graduate School of Medicine , Osaka, Japan .
authors.forename: Satsuki
authors.initials: S
authors.lastname: Nishigaki
authors.affiliation: 1 Department of Pediatrics, Osaka City University Graduate School of Medicine , Osaka, Japan .
authors.forename: Takashi
authors.initials: T
authors.lastname: Hamazaki
authors.affiliation: 1 Department of Pediatrics, Osaka City University Graduate School of Medicine , Osaka, Japan .
authors.forename: Keinosuke
authors.initials: K
authors.lastname: Fujita
authors.affiliation: 2 Department of Pediatrics, Hokkaido University School of Medicine , Sapporo, Japan .
authors.forename: Shuntaro
authors.initials: S
authors.lastname: Morikawa
authors.affiliation: 2 Department of Pediatrics, Hokkaido University School of Medicine , Sapporo, Japan .|3 Department of Pediatrics, Jichi Children's Medical Center Tochigi , Shimotsuke, Japan .
authors.forename: Toshihiro
authors.initials: T
authors.lastname: Tajima
authors.affiliation: 1 Department of Pediatrics, Osaka City University Graduate School of Medicine , Osaka, Japan .
authors.forename: Haruo
authors.initials: H
authors.lastname: Shintaku
mesh_terms: D000328:Adult; D003409:Congenital Hypothyroidism / Q000188:drug therapy / Q000235:genetics*; D004252:DNA Mutational Analysis; D020249:Hormone Replacement Therapy; D006801:Humans; D007037:Hypothyroidism / Q000188:drug therapy / Q000235:genetics*; D007136:Immunoglobulins / Q000235:genetics*; D007223:Infant; D008297:Male; D008565:Membrane Proteins / Q000235:genetics*; D009154:Mutation; D010375:Pedigree; D013974:Thyroxine / Q000627:therapeutic use
chemical_list: C112314:IGSF1 protein, human; D007136:Immunoglobulins; D008565:Membrane Proteins; D013974:Thyroxine
keywords: IGSF1; central hypothyroidism; neurological development; pituitary; prolonged jaundice