First Report of Familial Dysalbuminemic Hyperthyroxinemia With an ALB Variant

Familial dysalbuminemic hyperthyroxinemia (FDH) is an inherited disease characterized by increased circulating total thyroxine (T4) levels and normal physiological thyroid function. Heterozygous albumin gene (ALB) variants have been reported to be the underlying cause of FDH. To our knowledge, there have been no confirmed FDH cases in Korea. We recently observed a female patient with mild T4 elevation (1.2 to 1.4-fold) and variable levels of free T4 according to different assay methods. Upon Sanger sequencing of her ALB, a heterozygous c.725G>A (p.Arg242His) variant was identified. The patient's father and eldest son had similar thyroid function test results and were confirmed to have the same variant. Although the prevalence of FDH might be very low in the Korean population, clinical suspicion is important to avoid unnecessary evaluation and treatment.

Prevalence of abnormal maternal TPO-Ab and TSH levels in pregnant women in the Malaysian population

Background: Undiagnosed thyroid disease is a common problem with significant public health implications. This is especially true during pregnancy, when the health of the mother and child can be adversely affected by abnormal thyroid function. Measurement of thyroid stimulating hormone (TSH) and antibodies to thyroid peroxidase (TPO-Ab) are two important ways to assess maternal thyroid status.Objective: The purpose of our evaluation was to determine the prevalence of abnormal thyroid function by testing a population of pregnant women at the Obstetric Clinic, University Malaya Medical Center, Malaysia.Method: We assayed serum samples (n= 609) of pregnant partum women (age range 20-45) on the Abbott AxSYM platform using a 3rd generation TSH assay and TPO-Ab. Results outside the manufacturer’s reference range (TSH= 0.47-4.64 μIU/mL; TPO Ab \< 12 IU/mL) were considered to be abnormal.Result: Overall prevalence for an abnormal test result was 21.3%. Across the different age groups, the average prevalence for an abnormal result was TSH=10.3% and TPO-Ab=10.8%. If, as in the NACB thyroid testing guidelines, a more narrow TSH reference range (0.4-2.5 μIU/mL) was applied to our data, the prevalence of abnormal TSH results increased to 14.9%.Conclusion: Our data show a high prevalence of abnormal thyroid function in this population, and suggest that routine screening of pregnant women for thyroid dysfunction may be appropriate in addition to routine prenatal care.