NUCLEOLIN and major depressive disorder: Furthermore, the NCL interaction network emphasized by the DAPPLE analysis included PIK3C2A, which too surpassed exome-wide significance in the Faroese population and is supported by genome-wide significance in GWAS combining bipolar disorder and schizophrenia.4 Both PIK3C2A and PITPNM2 are part of the phosphatidylinositol pathway, which have been widely implicated in mental disorders such as bipolar, depression and schizophrenia4, 51