An exonic splicing enhancer mutation in DUOX2 causes aberrant alternative splicing and severe congenital hypothyroidism in Bama pigs.

Chunwei Cao,Jing Yao,Nan Zhang,Qi Zhou,Qitao Jia,Ailing Luo,Yongshun Li,Ying Zhang,Yanfang Wang,Ruigao Song,Qianlong Hong,Xiao Wang,Jianguo Zhao,Hongmei Wang,Qiantao Zheng,Guosong Qin,Hongyong Zhang

doi:10.1242/dmm.036616

Abstract

ABSTRACTPigs share many similarities with humans in terms of anatomy, physiology and genetics, and have long been recognized as important experimental animals in biomedical research. Using an N-ethyl-N-nitrosourea (ENU) mutagenesis screen, we previously identified a large number of pig mutants, which could be further established as human disease models. However, the identification of causative mutations in large animals with great heterogeneity remains a challenging endeavor. Here, we select one pig mutant, showing congenital nude skin and thyroid deficiency in a recessive inheritance pattern. We were able to efficiently map the causative mutation using family-based genome-wide association studies combined with whole-exome sequencing and a small sample size. A loss-of-function variant (c.1226 A>G) that resulted in a highly conserved amino acid substitution (D409G) was identified in the DUOX2 gene. This mutation, located within an exonic splicing enhancer motif, caused aberrant splicing of DUOX2 transcripts and resulted in lower H2O2 production, which might cause a severe defect in thyroid hormone production. Our findings suggest that exome sequencing is an efficient way to map causative mutations and that DUOX2D409G/D409G mutant pigs could be a potential large animal model for human congenital hypothyroidism.

Highlights

Pigs are considered to be one of the major livestock and are increasingly used in biomedical research (Swindle et al, 2012)
Our findings indicate that the DUOX2D409G/D409G mutant pigs could be used as a potential large animal model for human congenital hypothyroidism
This study demonstrates that whole-exome sequencing integrated with family-based GWAS is a robust approach to reveal the causative mutation in ENU-induced mutant pigs

Summary

Introduction

Pigs are considered to be one of the major livestock and are increasingly used in biomedical research (Swindle et al, 2012). Received 25 July 2018; Accepted 3 December 2018 models for human diseases – such as Alzheimer’s disease, retinitis pigmentosa, spinal muscular atrophy, cardiovascular diseases and cancers – have been created for the purpose of biomedical research (Prather et al, 2013). The pigs are regarded as ideal organ donors for xenotransplantation into humans (Lai et al, 2002), and as high efficiency bioreactors for the production of pharmaceuticals (Zhao et al, 2015). With the rapid development of genome engineering tools, pigs will become an increasingly important experimental animal for biomedical research

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