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Thyroid Function Tests in Subjects with a Genetic Isoelectric Focusing Variant TBG

  • Junta Takamatsu
  • Michiyasu Ando
  • David Sarne
  • Samuel Refetoff

Abstract

A variant thyroxine-binding globulin (TBG) with slower migration on isoelectric focusing (TBG-S) has been found in some American Blacks. It is inherited as an X-chromosome-linked trait. Hemizygous males with TBGS exhibit TBG bands shifted cathodally. Heterozygous females with TBG-CS, show the summation pattern of TBG bands corresponding to sera from subjects with only TBG-S and those with only the common type of TBG (TBG-C). Because the effect of TBG-S on thyroid function has not been studied in detail, we compared data of thyroid function tests in sex and age matched subjects belonging to four TBG genotypes (10 males each with TBG-S vs. TBG-C, and 10 females each with TBG-CS vs. TBG-CC). The mean serum T4 level of the group of males with TBG-S was 6.79 + 1.52 (SD) μg/dl, significantly lower than that of the group of males with TBG-C (8.49 + 1.29 lig/μl, p<0.02). A significant concomitant reduction in the mean serum TBG concentration was found in the group of males with TBG-S as compared to that with TBG-C (1.41 + 0.30 mg/dl vs. 1.72 + 0.29 mg/dl, p<0.05). Mean values of serum free T4 concentrations and other tests of thyroid function, including TSH levels, were not significantly different among the four groups matched by age and paired by sex. Although the reason for the reduced serum TBG concentration in subjects with TBG-S remains unclear the associated reduction of serum T4 levels is not accompanied by hypothyroidism.

Keywords

Thyroid Function Thyroid Function Test Heterozygous Female American Black Hemizygous Male 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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References

  1. 1.
    Daiger SP, Rummel DP, Wang L, et al. Am J Hum Genet 33: 640, 1981.PubMedGoogle Scholar
  2. 2.
    Grimaldi S, Bartalena L, Ramacciotti C, et al. J Clin Endocrinol Metab 57: 118, 1983.CrossRefGoogle Scholar
  3. 3.
    Kamboh MI and Kirwood C. Am J Hum Genet 36: 646, 1984.PubMedGoogle Scholar
  4. 4.
    Refetoff S, Murata Y, Vassart G, et al. J Clin Endocrinol Metab 59: 269, 1984.PubMedCrossRefGoogle Scholar
  5. 5.
    Refetoff S, Hagen SR, and Selenkow HA. J Nucl Med 13: 2, 1972.PubMedGoogle Scholar
  6. 6.
    Refetoff S, Robin NI, and Alper CA. J Clin Invest 51: 848, 1972.PubMedCrossRefGoogle Scholar
  7. 7.
    Refetoff S and Murata Y. J Clin Endocrinol Metab 60: 356, 1985.PubMedCrossRefGoogle Scholar
  8. 8.
    Murata Y and Refetoff S. Endocrinology suppl 115: T45, 1984.Google Scholar

Copyright information

© Springer Science+Business Media New York 1986

Authors and Affiliations

  • Junta Takamatsu
    • 1
  • Michiyasu Ando
    • 1
  • David Sarne
    • 1
  • Samuel Refetoff
    • 1
  1. 1.The Thyroid Study Unit, Departments of Medicine and PediatricsThe University of ChicagoChicagoUSA

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