LF tissues from LSS and non-LSS patients revealed that LF tissues from LSS patients express a higher level of TGF-β1 and phosphorylated SMAD3, suggesting that activated TGF-β signaling promotes the synthesis of COLI and COLIII through epidermal growth factor (EGF) during hypertrophy [81]. Here, TGFB1 is linked to Leigh syndrome.