INSR and early-onset autosomal dominant Alzheimer disease: Although the role that the insulin receptor may play in these disorders is still a puzzle, enhanced brain insulin receptor signaling has been used to treat schizophrenia patients early in the mid-20th century [148,149] and insulin sensitizing drugs are now in clinical trials for the treatment of Alzheimer's disease [150-152], highlighting its importance in both neuronal developmental and degenerative diseases.