First report of inherited thyroxine-binding globulin deficiency in Iran caused by a known de novo mutation in SERPINA7
- PMID: 27331012
- PMCID: PMC4909823
- DOI: 10.1016/j.ymgmr.2016.06.001
First report of inherited thyroxine-binding globulin deficiency in Iran caused by a known de novo mutation in SERPINA7
Abstract
Background: Thyroxine-binding globulin (TBG) is the main transporter of thyroid hormones in human serum, encoded by the gene TBG (SERPINA7), located in long arm of X-chromosome (Xq21-q22). Deficiency of SERPINA7 (serum protease inhibitor, clade A [alpha-1 antiproteinase, antitrypsin], member 7) leads to inherited TBG deficiency. Several mutations have been reported in the coding and noncoding regions of SERPINA7 in association with TGB deficiency.
Methods: Automated chemiluminescence immunoassays were used to determine TSH, free and total T4 and T3 (fT4, TT4, TT3) and TBG. Direct DNA sequencing identified the mutation in SERPINA7.
Results: We present a 3 and 4/12 year old boy, born premature, who was mismanaged as hypothyroidism before referral to our center, and was diagnosed with TBG deficiency at our center with a hemizygous substitution in exon 1, position c.347T > A, leading to replacement of isoleucine for arginine in position 96 (considering the first 20 amino acid signal peptide).
Conclusion: This known mutation, reported as the first SERPINA7 mutation in Iran, emphasizes the point that endocrinologists should pay more attention to inherited TBG to prevent unnecessary treatment.
Keywords: Iran; Mutation; SERPINA7; TBG.
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