NIPA2 and attention deficit-hyperactivity disorder: Moreover, mutations in each gene were associated with different disorders: NIPA1 with autosomal-dominant hereditary spastic paraplegia (17), NIPA2 with childhood absence epilepsy (19), TUBGCP5 with ADHD and obsessive-compulsive disorder (20), and CYFIP1 with increasing susceptibility to ASD (51) and with schizophrenia (52).