XK and connective tissue disorder: Of the nine participants with non-IUIS molecular diagnoses, six were primarily neurological (ARID2-related Coffin-Siris syndrome, Charcot-Marie-Tooth Disease Type 1A, CLN3-related Batten disease, tetrasomy 9p, XK-associated McLeod syndrome, and 16p11.2 duplication), one was a connective tissue disorder (SMAD3-related Loeys-Dietz syndrome), one was metabolic (OTC-related ornithine transcarbamylase deficiency), and one was respiratory (DNAH5-related primary ciliary dyskinesia).