SNUPN and muscular dystrophy: Functional studies showed that SNUPN variants impair snurportin-1 function through reduced binding affinity to importin-β and impaired folding, leading to disturbed nuclear import of small nuclear ribonucleoproteins and downstream splicing.<h4>Interpretation</h4>Our work expands the phenotype of SNUPN-related muscular dystrophy and provides more insights into their pathological profile.