When we compared between the disease groups (i.e., HHT vs. CCM, HHT vs. sporadic BAVM, and CCM vs. sporadic BAVM), the only significant finding was an elevation of TGFβ1 in CCM samples compared to sporadic BAVM samples (PI = 2.30, 95% CI 1.45 to 3.63, p < 0.001, q = 0.034) (Additional file 1: Table S1). This evidence concerns the gene TGFB1 and cerebral cavernous malformation.