ITIH4 and major depressive disorder: Several novel isoforms (including 5 of the top 20 by expression, Additional file 4: Fig. R) predicted a novel exon 22 skipping event in the SZ and MDD risk gene ITIH4. Targeted mass spectrophotometry (MS) confirmed a novel junction between exons 21 and 23 (ETLFSVMPG//PVLPGGALGISSSIR) created due to skipping of exon 22 (Fig. 6A, Additional file 2: Fig. S12).