About the Authors

Kirsi H Pietiläinen

Contributed equally to this work with: Kirsi H Pietiläinen, Jussi Naukkarinen

Affiliations Obesity Research Unit, Department of Psychiatry, Helsinki University Central Hospital, Helsinki, Finland , Department of Medicine, Division of Diabetes, Helsinki University Central Hospital, Helsinki, Finland , Finnish Twin Cohort Study, Department of Public Health, University of Helsinki, Helsinki, Finland

Jussi Naukkarinen

Contributed equally to this work with: Kirsi H Pietiläinen, Jussi Naukkarinen

Affiliations Department of Molecular Medicine, National Public Health Institute, Helsinki, Finland , Department of Medical Genetics and Research Program of Molecular Medicine, University of Helsinki, Finland

Aila Rissanen

Affiliation Obesity Research Unit, Department of Psychiatry, Helsinki University Central Hospital, Helsinki, Finland

Juha Saharinen

Affiliations Department of Molecular Medicine, National Public Health Institute, Helsinki, Finland , Department of Medical Genetics and Research Program of Molecular Medicine, University of Helsinki, Finland

Pekka Ellonen

Affiliations Department of Molecular Medicine, National Public Health Institute, Helsinki, Finland , Department of Medical Genetics and Research Program of Molecular Medicine, University of Helsinki, Finland

Heli Keränen

Affiliations Department of Molecular Medicine, National Public Health Institute, Helsinki, Finland , Department of Medical Genetics and Research Program of Molecular Medicine, University of Helsinki, Finland

Anu Suomalainen

Affiliation Research Program of Molecular Neurology and Department of Neurology, University of Helsinki and Helsinki University Central Hospital, Helsinki, Finland

Alexandra Götz

Affiliation Research Program of Molecular Neurology and Department of Neurology, University of Helsinki and Helsinki University Central Hospital, Helsinki, Finland

Tapani Suortti

Affiliation VTT Technical Research Centre of Finland, Espoo, Finland

Hannele Yki-Järvinen

Affiliation Department of Medicine, Division of Diabetes, Helsinki University Central Hospital, Helsinki, Finland

Matej Orešič

Affiliation VTT Technical Research Centre of Finland, Espoo, Finland

Jaakko Kaprio

Affiliations Finnish Twin Cohort Study, Department of Public Health, University of Helsinki, Helsinki, Finland , Department of Mental Health and Alcohol Research, National Public Health Institute, Helsinki, Finland

Leena Peltonen

To whom correspondence should be addressed. E-mail: leena.peltonen@ktl.fi

Affiliations Department of Molecular Medicine, National Public Health Institute, Helsinki, Finland , Department of Medical Genetics and Research Program of Molecular Medicine, University of Helsinki, Finland , The Wellcome Trust Sanger Institute, Cambridge, United Kingdom , Broad Institute, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America

Competing Interests

The authors have declared that no competing interests exist.

Author Contributions

AR initiated the concept of the study and KHP, AR, HYJ, JK, and LP designed it. JK was responsible for collecting the study base from which the discordant pairs were selected. KHP conducted the trial and AR, HYJ, and JK supervised its progression. LP carried the overall responsibility of the study design of genome-wide transcription and pathway analyses conducted by JN and JS. AS and LP supervised the mitochondrial sequence analyses performed by PE, HK, and AG. TS and MO analyzed serum BCAAs and their ketoacids. KHP and JS performed the statistical analyses. All authors contributed to interpretation of the data and KHP, JN, AR, MO, and LP, wrote the manuscript.