Pelizaeus-Merzbacher disease (PMD) is neurodegenerative leukodystrophy caused by dysfunction of the proteolipid protein 1 (PLP1) gene on Xq22, which codes for an essential myelin protein. As an X-linked condition, PMD primarily affects males; however there have been a small number of affected females reported in the medical literature with a variety of different mutations in this gene. No affected females to date have a deletion like our patient. In addition to this, our patient has skewed X chromosome inactivation which adds to her presentation as her unaffected mother also carries the mutation.