Yonsei Med J.  2017 Nov;58(6):1160-1169. 10.3349/ymj.2017.58.6.1160.

Identification and Functional Characterization of ST3GAL5 and ST8SIA1 Variants in Patients with Thyroid-Associated Ophthalmopathy

• Park HJ
• Kim JH
• Yoon JS
• Choi YJ
• Choi YH
• Kook KH
• Choi JH

• KMID: 2418898
• DOI: http://doi.org/10.3349/ymj.2017.58.6.1160

Abstract

PURPOSE
This study was conducted to identify and to functionally characterize genetic variants in ST3GAL5 and ST8SIA1 in Korean patients with thyroid-associated ophthalmopathy (TAO).
MATERIALS AND METHODS
Genetic analyses were conducted using DNA samples from TAO patients (n=50) and healthy subjects (n=48) to identify TAO-specific genetic variants of ST3GAL5 or ST8SIA1. The effect of each genetic variant on the transcription or expression of these genes was examined. Additionally, correlations between functional haplotypes of ST3GAL5 or ST8SIA1 and clinical characteristics of the patients were investigated.
RESULTS
Six promoter variants and one nonsynonymous variant of ST3GAL5 were identified, and four major promoter haplotypes were assembled. Additionally, three promoter variants and two major haplotypes of ST8SIA1 were identified. All ST3GAL5 and ST8SIA1 variants identified in TAO patients were also found in healthy controls. Promoter activity was significantly decreased in three promoter haplotypes of ST3GAL5 and increased in one promoter haplotype of ST8SIA1. Transcription factors activating protein-1, NKX3.1, and specificity protein 1 were revealed as having roles in transcriptional regulation of these haplotypes. The nonsynonymous variant of ST3GAL5, H104R, did not alter the expression of ST3GAL5. While no differences in clinical characteristics were detected in patients possessing the functional promoter haplotypes of ST3GAL5, exophthalmic values were significantly lower in patients with the ST8SIA1 haplotype, which showed a significant increase in promoter activity.
CONCLUSION
These results from genotype-phenotype analysis might suggest a possible link between the ST8SIA1 functional promoter haplotype and the clinical severity of TAO. However, further studies with larger sample sizes are warranted.

Keyword

Exophthalmos; Korea; sialyltransferases; single nucleotide polymorphism; thyroid-associated ophthalmopathy

MeSH Terms

Adult
Case-Control Studies
Female
Gene Expression Regulation
Genetic Variation
Graves Ophthalmopathy/ethnology/*genetics
Haplotypes
Humans
Male
Middle Aged
Phenotype
Polymorphism, Single Nucleotide
Promoter Regions, Genetic
Sialyltransferases/*genetics/metabolism
Transcription Factors
Transcription Factors
Sialyltransferases