<s>[INST] <<SYS>> This is a medical question of type : causes <</SYS>> What causes Microcephalic osteodysplastic primordial dwarfism type 1 ? [/INST] What causes microcephalic osteodysplastic primordial dwarfism type 1 (MOPD1)? Microcephalic osteodysplastic primordial dwarfism type 1 (MOPD1) has been shown to be caused by mutations in the RNU4ATAC gene. </s>