ALDH4A1 and autism spectrum disorder: Specifically, biallelic variants were detected in (i) ALDH4A1 gene which is associated with hyperprolinemia type II (OMIM#239,510), (ii) NEUROG1 gene which is associated with congenital cranial dysinnervation disorder and autism spectrum disorder [50], (iii) KDM6A gene which is associated with Kabuki syndrome 2 (OMIM#300,867), (iv) LMAN2L gene which is associated with mental retardation 52 (OMIM#616,887) and, (v) ALDH7A1 gene which is associated with pyridoxine dependent epilepsy (OMIM#266,100).