Human 3M syndrome has been subcategorized into three types, 3M1 (OMIM 273750) with causal mutations located in the Cullin 7 (CUL7) gene, 3M2 (OMIM 612921) with causal mutations located in the Obscurin like cytoskeletal adaptor 1 (OBSL1) gene, and 3M3 (OMIM 614205 [12];) with causal mutations located in the Coiled-Coil Domain Containing 8 (CCD8) gene. The gene discussed is CUL7; the disease is 3M syndrome.