To directly test SEMA5A expression in brains from autistic patients, tissue samples from 20 cases with a primary diagnosis of autism and 10 controls were obtained through the Autism Tissue Program and the Harvard Brain Bank. Samples were dissected from Brodmann area 19 of the occipital lobe cortex, a region demonstrating differences between autism cases and controls in functional imaging studies, and subjected to quantitative PCR 8. SEMA5A expression, determined relative to MAP2 (neuron specific), was significantly lower in autism brains than controls after adjustment for the age at brain acquisition, post-mortem interval, and sex (P = 0.024, Figure 2).
