Six “spliceosomal” genes and one “non-spliceosomal” disease-causative gene, SF3B2, PRPF3, THOC1, CWC27, NKAP, MOB2, and ADPRHL2, are connected to severe neurological and/or developmental diseases including craniofacial microsomia, hearing loss, an X-linked intellectual developmental disorder, different types of retinitis pigmentosa, and childhood-onset neurodegeneration. This evidence concerns the gene CWC27 and craniofacial microsomia.