TGFB1 and multiminicore myopathy: Similarly, the latest study by Shusuke Yamamoto et al. pointed out that the expression level of TGF-β1 in the cerebrospinal fluid of MMD patients was significantly increased, which may lead to the proliferation of fibroblasts in the arachnoid and their differentiation into myofibroblasts, thereby producing excess collagen, which in turn leads to the growth of malformed blood vessels in MMD.