Effects of creatine supplementation in Rett syndrome: a randomized, placebo-controlled trial.

OBJECTIVE

To evaluate the effects of creatine monohydrate (CMH) supplementation on global DNA methylation and disease-specific clinical symptoms in female patients with Rett syndrome (RTT).

METHODS

Double-blind, randomized, placebo-controlled crossover trial of female patients with RTT. Participants received 200 mg/kg of either CMH or placebo daily for 6 months and switched following a 4-week washout period. Primary endpoints were change in global DNA methylation and in a RTT-specific symptom score as defined by medical history and clinical evaluation with Rett Syndrome Motor and Behavioral Assessment. Secondary endpoints were changes in biochemical markers of methionine metabolism.

RESULTS

Eighteen female patients aged 3 to 25 years with clinically diagnosed typical RTT and MECP2 mutation at clinical Stages III or IV were studied. CMH supplementation resulted in a statistically significant increase of global methylation by 0.11 (95% confidence interval 0.03-0.19, p = .009) compared with placebo. Total and subscores of Rett Syndrome Motor and Behavioral Assessment tended to improve but without statistical significance.

CONCLUSION

CMH supplementation increases global DNA methylation statistically significantly. Scores were lower for creatine than for placebo reflecting clinical improvement but not reaching statistical significance. Biochemical variables of methionine-homocysteine remethylation are unaffected. Multicenter studies are urgently warranted to evaluate the long-term effects of CMH supplementation in an optimally homogenous RTT population over a prolonged period.