ARX and neurodevelopmental disorder: As ARX is located in Xp21.3, loss-of-function (LoF) and partial-LoF mutations contribute to a nearly continuous series of X-chromosome-linked neurodevelopmental disorders (NDDs) ranging from lissencephaly with abnormal genitalia (XLAG; MIM 300215), developmental and epileptic encephalopathy type 1 (DEE1; MIM 308350), X-linked intellectual disability (XLID; 300419), ID with hand dystonia (Partington syndrome; MIM 309510), and autism [8,9,10,11,12].