Notably, the strongest causal association was found between serum WFIKKN1 and schizophrenia (Padj = 9.12 × 10−43); WFIKKN1 (WAP, Kazal, immunoglobulin, Kunitz and NTR domain-containing protein 1) has not been associated with any neuropsychiatric disorder to date, but is highly expressed in the brain (GTEx) and regulates the activity of several growth and differentiation factors29. The gene discussed is WFIKKN1; the disease is schizophrenia.