CCDC8 and 3M syndrome: The 3M syndrome is causally linked with the mutations on the genes CUL7, OBSL1, and CCDC8. A previous study showed that patients who were diagnosed with the 3M syndrome, having mutations on these genes, tended to be shorter to the degree of a -5.7 SD score for CUL7, a -4.7 SD score for OBSL1, and a -4.1 SD score for CCDC8 (6).