Thyroid function tests in patients with familial dysalbuminaemic hyperthyroxinaemia (FDH)

M F Stewart, W A Ratcliffe, I Roberts

Research output: Contribution to journalArticlepeer-review

Abstract

Two patients with familial dysalbuminaemic hyperthyroxinaemia (FDH) are described in whom the albumin variant resulted in raised total T4 levels, and artefactually raised free T4 using a 'single-step' technique employing an analogue of T4 as tracer. The first patient was clinically euthyroid and presented with relapse of schizophrenia and abnormal thyroid function tests (total T4 336 nmol/L, total T3 4.2 nmol/L, TSH 1.8 mU/L, free T4 73 pmol/L). These results led to diagnostic confusion and the patient was treated with a short course of anti-thyroid drugs. The second patient had signs and symptoms of thyrotoxicosis at her first visit but was clinically euthyroid 5 months later when she was 10 weeks pregnant. Thyroid function tests were total T4 259 nmol/L, total T3 3.6 nmol/L, TSH 3.8 mU/L, free T4 46 pmol/L. Further studies showed both patients to be biochemically euthyroid. A variant albumin was confirmed in both patients by a screening test for FDH and by reverse-flow electrophoresis. Family studies on 10 relatives of the first patient identified eight with FDH. A simple screening procedure for the indentification of FDH is described and the use of laboratory tests in suspected cases is discussed.

Original languageEnglish
Pages (from-to)59-64
Number of pages6
JournalAnnals of Clinical Biochemistry
Volume23 ( Pt 1)
DOIs
Publication statusPublished - Jan 1986

Keywords

  • Adult
  • Euthyroid Sick Syndromes/blood
  • Female
  • Humans
  • Hyperthyroxinemia/diagnosis
  • Pedigree
  • Schizophrenia/blood
  • Serum Albumin/genetics
  • Thyroid Function Tests
  • Thyroxine/blood

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