The present invention relates to a transcription factor EB (TFEB) protein, ortholog, recombinant or synthetic or biotechnological functional derivative thereof, allelic variant thereof and fragments thereof； a chimeric molecule comprising the TFEB protein, ortholog, recombinant or synthetic or biotechnological functional derivative thereof, allelic variant thereof and fragments thereof； a polynucleotide coding for said protein or ortholog, recombinant or synthetic or biotechnological functional derivative thereof, allelic variant thereof and fragments thereof； a vector comprising said polynucleotide； a host cell genetically engineered expressing said polypeptide or a pharmaceutical composition for use in the treatment or/and prevention of a glycogen storage disease. Preferably of Pompe or Danon disease.
