For example, why variants in the U5 snRNP genes PRPF6, PRPF8 and SNRNP200 are associated with retinal degeneration in adRP, while variants in the U5 snRNP genes EFTUD2 and TXNL4A are linked to craniofacial disorders, is not understood. This evidence concerns the gene PRPF6 and retinal degeneration.