Mutations in BCS1L comprise a wide spectrum of pathologies, including: GRACILE syndrome (growth retardation, aminoaciduria, cholestasis, iron overload, lactic acidosis, early death) [82,83,84,85,86,87,88]; Björstand syndrome, characterized by hearing loss and pili torti [89,90,91,92,93,94]; encephalopathy [95,96,97,98]; lactic acidosis, liver dysfunction and tubulopathy [99,100,101,102]; muscle weakness, focal motor seizures and optic atrophy [103], among others. This evidence concerns the gene BCS1L and lactic acidosis.