FADS6 and infection: Further, we found that the rare signature patients might have impaired immunity to deal with such infections through the downregulation of genes involved in chemokine receptor 6 (CCR6)-dependent bactericidal activity (including DEFB1), and the downregulation of genes involved in de novo biosynthesis of steroids from cholesterol (HSD17B6, GREM2, FADS6 and AADAC).