FSTL3 and chronic kidney disease: MR associations with nominal P < 0.05 were observed for several proteins including two BMP antagonists, follistatin-related protein 3 (FSTL3) and twisted gastrulation protein homolog 1 (TWSG1), as well as CILP2, a protein associated with a lower risk of CKD progression that inhibits fibrosis, all of which replicated in ARIC.