Surprisingly, patients with deficiencies in proteins affecting peroxisome dynamics (e.g., MFF, PEX11β) exhibit neurological symptoms despite little or no alterations to the levels of peroxisomal metabolites, in contrast to diseases where peroxisomal function is impaired, such as peroxisome biogenesis disorders (Carmichael et al., 2022). Here, MFF is linked to peroxisomal disease.