and suggest a strong association with the cortex, which is the seat of memory, attention, thought, language, and consciousness in the brain. Recent reports comparing autistic and control brains suggested an attenuation of normal differential gene expression between frontal and temporal cortex in autistic brains42. Moreover, as autism is a neurodevelopmental disorder we expect NHE9 to play a functional role during development. Indeed, in situ hybridization data of the developing mouse brain43 revealed differential expression of NHE9 during the various stages of development (Figure 4B). NHE9 expression was consistently high in the prosomere 1(p1) region of the diencephalon in the embryonic forebrain (Figure 4C). In addition to the forebrain, expression levels of NHE9 were also high in the midbrain by postnatal day 4(P4). Although the p1 and midbrain showed high levels of NHE9 expression in P28 pups, highest levels of NHE9 were observed in the telencephalic vesicle of the forebrain. Pontomedullary region of the hindbrain also showed NHE9 expression comparable to the p1 region by P28. Finally, the adult brain is primarily composed of two broad classes of cells: neurons and glial cells. We compared the mRNA transcript levels of NHE9 in neurons and astrocytes, the most abundant macroglial cells
