<s>[INST] <<SYS>> This is a medical question of type : causes <</SYS>> What causes Megalencephaly, polymicrogyria, and hydrocephalus (MPPH) syndrome ? [/INST] What causes megalencephaly, polymicrogyria, and hydrocephalus (MPPH) syndrome? The cause of MPPH syndrome is unknown. Infection during pregnancy or fetal accident is thought to be unlikely. </s>