The analysis of four additional genes: the well-studied gene CHI3L2 (Chitinase 3 like 2), the autism and schizophrenia candidate gene DGCR8 (DiGeorge Critical Region-8) and the Alzheimer candidate genes GSTM3 and GSTM5 (Glutathione S-transferase mu-1/5) can be found in Supplementary Files 9–11. The gene discussed is DGCR8; the disease is autism.