Importantly, mutations in RNU4ATAC have been shown to affect the formation of minor spliceosome and cause Taybi-Linder syndrome/microcephalic osteodysplastic primordial dwarfism type 1 (TALS/MOPD1) [32,33], illustrating that not only malfunctioning of proteins but also of U snRNAs can cause disease. Here, RNU4ATAC is linked to microcephalic osteodysplastic primordial dwarfism type I.