Efficacy and Safety of the Treatment of Pyruvate Dehydrogenase Deficiency Patients With Glycerol Phenylbutyrate (RAVICTI)

Inclusion Criteria: * Child from 2 to 17 years of age Or * Adult from 18 to 25 years of age * With a PDH deficiency confirmed by molecular biology: * a class 4 or 5- missense variant on the PDHA1 gene or * one homozygous variant or two mixed heterozygous variants of class 4 or 5 that are missense variants on PDHB or DLAT genes or * one homozygous variant or two mixed heterozygous variants of class 4 or 5 on PDHX genes (including non-sense and frameshift variants, and intragenic deletions * For females of childbearing potential, negative bHCG and effective method of contraception (sexual abstinence, hormonal contraception containing ethinylestradiol and levonorgestrel, intrauterine device or hormone-releasing system, cap, diaphragm or sponge with spermicide, condom) until 30 days after the end of study. For male, an effective method of contraception (sexual abstinence, condom) until 30 days after the end of study * Signature of consent by the legal representative * Beneficiary of a social security coverage (affiliated or entitled) Exclusion Criteria: * Patient with E3 deficiency due to pathogenic mutation in DLD gene * Patient with non-sense mutation on PDHB or DLAT gene, and male patient with non-sense mutation or PDHA1 gene. * Patient with planned hip or scoliosos surgery during the study timeframe. * Patient whose parents / legal representative refuse flu vaccine. * Treatment change during the last 3 months prior inclusion (ketogenic diet and/or B1 vitamin) * Hypersensitivity to Glycerol Phenylbutyrate or to any of the excipients * No disease requiring Glycerol Phenylbutyrate (Hyperammonemia due to urea cycle disease or other aetiology) * Pregnant or breastfeeding women * Participation to another clinical trial on medicinal products for human use