It has been purported that there is a genetic risk factor for NMS, since identical twins have both presented with NMS in one case, and a mother and two of her daughters have presented with NMS in another case.
遺伝的リスク因子が存在すると推測されており、ある症例の中で一卵性双生児の両方がNMSを呈したり、別の症例では母親と娘2人がNMSを呈したことがある。