P1 PUF60 mutations and ciliopathies: a shared molecular mechanism?

Pathogenic PUF60 variants disrupt pre-mRNA splicing, leading to intellectual disability, developmental delay, and congenital heart defects. However, it is not fully understood why these variants lead to the clinical features associated with PUF60-related disorders. This work examines the impact of PUF60 variants on global splicing and gene expression via RNA sequencing. Transcriptomic analyses were performed on blood samples from six patients with pathogenic PUF60 variants and three controls. RNA-seq data were aligned using STAR and splicing and expression outliers were identified with rMATS and OUTRIDER, respectively. Differential expression and gene set enrichment analyses were conducted in R. RNA sequencing revealed few differentially expressed genes but identified numerous alternative splicing events, exon skipping the most common. The alternatively spliced genes were enriched in pathways related to cilium assembly and organisation, epigenetic regulation, and immune processes among others. Findings suggests that PUF60 variants drive a phenotype overlapping with ciliopathies due to a shared underlying mechanism. This could explain developmental abnormalities and organ defects such as the ophthalmic colobomas frequently reported in these patients. Moreover, alternative splicing events affecting immune-related genes may contribute to additional symptoms. This study enhances our understanding of PUF60-related disorders by highlighting the molecular disruptions driving their phenotypic diversity.