Scheme 1.

Study diagram. DS-EGCG: DS children treated with EGCG (Group 1); DS-CT: DS control group (Group 2); Healthy children (Group 3). N, patient number; safety evaluation was performed at baseline (T0), after 1 month (T1), after 3 months (T3) and after 6 months (T6) of EGCG supplementation. Griffiths Mental Developmental Scales—Extended Revised (GMDS-ER) evaluations were performed at T0 and at T6. Mitochondrial respiratory chain (MRC) complex activities were evaluated at T0, T1 and T6. Red lines indicate patient’s dropout.