Abstract
The mechanisms by which axonal degeneration occurs, even in the presence of apparently normal myelin sheaths, remain unknown. In this issue, Yin et al. (2016. J. Cell Biol. https://doi.org/10.1083/jcb.201607099) study mutant mice in which proteolipid protein is replaced by the peripheral myelin protein P(0) and describe a number of early axonal abnormalities, which together suggest that aberrant mitochondrial energy metabolism precedes axonal degeneration.