Familial dysalbuminaemic hyperthyroxinaemia with discordant thyroid function test results: two case reports

• Published in: Hong Kong medical journal = Xianggang yi xue za zhi Vol. 26; no. 3; p. 243
• Main Authors: Nike KC Lau, MA, Teresa KC Tsui, Kwok, Jeffrey SS, Cheung, Kitty KT, Chow, C C, Yeung, C K, Yuen, Y P
• Format: Journal Article
• Language: Chinese; English
• Published: Hong Kong Hong Kong Academy of Medicine 01-06-2020
• Subjects: Architects; Endocrinology; Family medical history; Hypothyroidism; Illnesses; Laboratories; Patients; Remission (Medicine); Thyroid diseases
• DOI: 10.12809/hkmj198035
• EISSN: 2226-8707
• ISSN: 1024-2708

[...]she was prescribed thyroxine replacement and her TSH was normalised (3.28 mIU/L) by June 2014. [...]testing in both patients for FDH targeting exon 7 of the ALB gene (OMIM *103600; Refseq NG_009291.1/NM_000477.6/NP_000468.1) showed heterozygous c.725G[greater than]A p.(Arg242His), a reported pathogenic variant in Chinese.1 Discussion Familial dysalbuminaemic hyperthyroxinaemia is an autosomal dominant condition caused by variants of albumin, the gene product of ALB.2 The prevalence of FDH has been estimated to be 0.01% in Caucasian populations but much higher (1.0%-1.8%) in Hispanic populations.3 The prevalence is uncertain in East Asian populations. [...]any previous thyroid function results should be reviewed. For FDH, it is important to note the assay platform used (hinted by the reference intervals provided), as a change of assay from one that is less affected by FDH to one that is prone to interference in FDH may give the clinician a false sense of an acquired condition. [...]the TSH level in patien