GAS1 and pathologic nystagmus: All patients survivors of β-oxidation disorders, organic acidurias (including biotinidase deficiency), urea cycle disorders and MSUD, GA 1, TYR 1, were asymptomatic, with the exception of 1 case of LCHAD with retinopathy; 2 cases of CblC with poor visual acuity, nystagmus, and developmental delay; and 2 cases of galactosaemia with ovarian failure and mild disability despite good metabolic control.