Mutations in EPAS1 in congenital heart disease in Tibetans.

Hong Pan,Tengyan Li,Qiuhong Chen,Binbin Wang,Shiming Liu,Shenggui Qi,Beihong Liu,Xu Ma

doi:10.1042/bsr20181389

Abstract

EPAS1 encodes HIF2 and is closely related to high altitude chronic hypoxia. Mutations in the EPAS1 coding sequence are associated with several kinds of human diseases, including syndromic congenital heart disease (CHD). However, whether there are rare EPAS1 coding variants related to Tibetan non-syndromic CHD have not been fully investigated. A group of 286 Tibetan patients with non-syndromic CHD and 250 unrelated Tibetan healthy controls were recruited from Qinghai, China. Sanger sequencing was performed to identify variations in the EPAS1 coding sequence. The novelty of identified variants was confirmed by the examination of 1000G and ExAC databases. Control samples were screened to establish that the rare candidate variants were specific to the Tibetan patients with non-syndromic CHD. Bioinformatics software was used to assess the conservation of the mutations and to predict their effects. The effect of EPAS1 mutations on the transcription of its target gene, VEGF, was assessed by dual-luciferase reporter assay. The mammalian two-hybrid assay was used to study the protein interactions between HIF2 and PHD2 or pVHL. We identified two novel EPAS1 mutations (NM_001430: c.607A>C, p.N203H; c.2170G>T, p.G724W) in two patients. The N203H mutation significantly affected the transcription activity of the VEGF promoter, especially in conditions of hypoxia. The N203H mutation also showed enhanced protein–protein interactions between HIF2 and PHD2, and HIF2 and pVHL, especially in conditions of hypoxia. However, the G724W mutation did not demonstrate the same effects. Our results indicate that EPAS1 mutations might have a potential causative effect on the development of Tibetan non-syndromic CHD.

Highlights

Congenital heart disease (CHD) is a problem with the structure and function of the heart that is present at birth
We identified two novel endothelial PAS domain protein 1 (EPAS1) mutations (NM 001430: c.607A>C, p.N203H; c.2170G>T, p.G724W) from a total of 286 Tibetan patients from Qinghai Province, China, with non-syndromic CHD (Figure 1, Table 1)
We report the identification of two novel mutations (NM 001430: c.607A>C, p.N203H; c.2170G>T, p.G724W) in the EPAS1 coding sequence in a group of Tibetan patients with non-syndromic CHD

Summary

Introduction

Congenital heart disease (CHD) is a problem with the structure and function of the heart that is present at birth. CHD affects ∼1% of live births and remains the leading cause of mortality from birth defects [1]. Most CHD patients have isolated heart defects and are referred to as non-syndromic. Many genes have been identified as causing rare inherited forms of CHD, the causes of most cases of sporadic CHD remain unknown [2]. Many reports indicate that genetic changes in the hypoxia-inducible factors (HIFs) pathway are linked to human adaptation to high altitude, especially in Tibetans [3]. Our previous study showed that the rate of CHD in Tibetan children increased significantly with increasing altitude levels, suggesting that CHD in Tibetan children may be associated with altitude levels, as well as with hypoxia [4]

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