Li Niu, Chang Guoying, Xu Yufei, Ding Yu, Li Guoqiang, Yu Tingting, Yao Ruen, Li Juan, Shen Yiping, Wang Xiumin, Wang Jian
Department of Medical Genetics and Molecular Diagnostic Laboratory, Shanghai Children's Medical Center, Shanghai Jiaotong University School of Medicine, Shanghai, China.
Department of Endocrinology and Metabolism, Shanghai Children's Medical Center, Shanghai Jiaotong University School of Medicine, Shanghai, China.
Am J Med Genet A. 2017 Dec;173(12):3189-3194. doi: 10.1002/ajmg.a.38473. Epub 2017 Sep 25.
Biallelic mutations in the GPD1 gene cause a rare autosomal recessive inherited disease known as transient infantile hypertriglyceridemia (OMIM #614480). To date, only five pathogenic variants have been reported in 15 patients from three studies. The clinical symptoms of the affected individuals present a certain degree of heterogeneity. Here, we describe a chinese adolescent patient who mainly presented with obesity, insulin resistance, fatty liver, and short stature. Targeted next-generation sequencing revealed a novel compound heterozygous variant in GPD1 gene (c.220-2A>G and c.820G>A; p.Ala274Thr). In vitro studies demonstrated that the Ala274Thr variant induced a decrease in GPD1 protein expression. Further in vitro investigation of the splicing pattern in a minigene construct in HEK293 cells showed that the c.220-2A>G variant generated an altered transcript with one cryptic splice site in exon 3, resulting in the loss of 69 bases in exon 3 (c.220_288del, p.74_96del). This is the first report involving an Asian who harbored GPD1 mutations. Our work not only expands the mutant spectrum of the GPD1 gene but also provides new insights on its resulting phenotype.
GPD1基因的双等位基因突变会导致一种罕见的常染色体隐性遗传病,称为短暂性婴儿高甘油三酯血症(OMIM #614480)。迄今为止,三项研究中的15名患者仅报告了五个致病变异。受影响个体的临床症状存在一定程度的异质性。在此,我们描述了一名中国青少年患者,其主要表现为肥胖、胰岛素抵抗、脂肪肝和身材矮小。靶向二代测序揭示了GPD1基因中的一种新的复合杂合变异(c.220-2A>G和c.820G>A;p.Ala274Thr)。体外研究表明,Ala274Thr变异导致GPD1蛋白表达下降。在HEK293细胞中对小基因构建体中的剪接模式进行的进一步体外研究表明,c.220-2A>G变异产生了一种改变的转录本,外显子3中有一个隐蔽剪接位点,导致外显子3中缺失69个碱基(c.220_288del,p.74_96del)。这是首例涉及携带GPD1突变亚洲人的报告。我们的工作不仅扩展了GPD1基因的突变谱,还为其导致的表型提供了新的见解。