Poison exons are naturally occurring, highly conserved alternative exons that contain a premature termination codon. Inclusion of a poison exon in a transcript targets the transcript for nonsense mediated decay, decreasing the amount of protein produced. Poison exons are proposed to play an important role in tissue-specific expression, development and autoregulation of gene expression. Recently, several studies that performed systematic investigations of alternative splicing in the brain have highlighted the abundance of transcripts containing poison exons, some of which are spliced in a cell type-specific manner. Pathogenic variants in or near poison exons that result in aberrant splicing have been identified in several genes including FLNA, SCN1A and SNRPB. Improved understanding of the role of poison exons in development and disease may present opportunities to solve previously undiagnosed disease and to develop therapeutic approaches in the future.

毒物外显子是天然存在的、高度保守的替代外显子，包含过早终止密码子。在转录物中包含有毒外显子靶向转录物进行无义介导的衰变，从而减少产生的蛋白质的量。毒物外显子被认为在基因表达的组织特异性表达、发育和自动调节中起重要作用。最近，几项对大脑中选择性剪接进行系统研究的研究强调了大量含有毒外显子的转录物，其中一些以细胞类型特异性方式进行剪接。已在包括FLNA、SCN1A和SNRPB在内的几个基因中鉴定出导致异常剪接的毒物外显子中或附近的致病变异。 更好地了解毒物外显子在发育和疾病中的作用可能为解决以前未确诊的疾病和开发未来的治疗方法提供机会。