目的:探讨1例非综合征型少牙症患者的致病基因,并分析其可能的致病机制。
方法:通过全外显子组测序(WES)和Sanger测序在一个少核家族中检测到该变体。生物信息学和结构分析用于分析变体。进行了功能研究,包括蛋白质印迹和免疫荧光分析以及荧光素酶报告基因测定,以探索功能作用。
结果:我们鉴定了一种新的PAX9移码变体(c.491-510delGCCCT-ATCACGGCGGCGGCC,p.P165Qfs*145)在DNA结合域之外,在中国家庭中引起常染色体显性遗传的非综合征性寡交。生物信息学和结构分析表明,该变异体是致病性的,在进化上是保守的,这些变化可能会影响蛋白质的稳定性或折叠。功能研究表明,激活BMP4启动子转录活性的能力显著降低,蛋白质产量显著下降,通过蛋白质印迹和免疫荧光分析评估。
结论:我们在一个中国家庭中发现了一种新的PAX9移码变种,导致非综合征性少牙。我们的发现表明,移码变异导致PAX9蛋白在牙列模式和随后的牙齿发育不全过程中的功能丧失,为PAX9移码变体的作用提供新的分子见解,并拓宽PAX9变体的致病谱。
OBJECTIVE: To investigate the pathogenic gene of a patient with nonsyndromic
oligodontia, and analyze its possible pathogenic mechanism.
METHODS: The variant was detected by whole exome sequencing (WES) and Sanger sequencing in a family with
oligodontia. Bioinformatic and structural analyses were used to analyze variant. Functional studies including western blotting and immunofluorescent analyses and luciferase reporter assay were conducted to explore the functional effects.
RESULTS: We identified a novel frameshift variant of PAX9 (c.491-510delGCCCT-ATCACGGCGGCGGCC, p.P165Qfs*145) outside the DNA-binding domain causing an autosomal-dominant nonsyndromic
oligodontia in a Chinese family. Bioinformatic and structural analyses revealed that the variant is pathogenic and conserved evolutionarily, and the changes might affect protein stability or folding. Functional studies demonstrate dramatically reduced ability in activating transcription activity of BMP4 promoter and a marked decrease in protein production, as evaluated by western blotting and immunofluorescent analyses.
CONCLUSIONS: We found a novel frameshift variant of PAX9 causing nonsyndromic
oligodontia in a Chinese family. Our findings indicate that frameshift variants cause loss of function of PAX9 protein during the patterning of the dentition and the subsequent tooth agenesis, providing new molecular insights into the role of frameshift variant of PAX9 and broaden the pathogenic spectrum of PAX9 variants.