RT Book, Section A1 Bashir, Khurram A2 Carney, Paul R. A2 Geyer, James D. SR Print(0) ID 6652443 T1 Chapter 17. Multiple Sclerosis White Matter T2 Pediatric Practice: Neurology YR 2010 FD 2010 PB The McGraw-Hill Companies PP New York, NY SN 978-0-07-148925-6 LK neurology.mhmedical.com/content.aspx?aid=6652443 RD 2024/03/19 AB Demyelination is a process that results in either partial or complete loss of the myelin sheath following a period of normal myelin development. Demyelinating diseases may affect the central nervous system (CNS), the peripheral nervous systems (PNS), or both. CNS demyelination may occur as a result of direct damage to the myelin sheath and/or the oligodendrocytes (primary demyelination), or is secondary to axonal damage with subsequent disruption of the axon-glia interaction essential to maintain normal myelination (secondary demyelination). Acquired CNS demyelinating diseases include self-limited monophasic disorders, such as acute disseminated encephalomyelitis (ADEM), as well as chronic, recurrent conditions such as multiple sclerosis (MS) and neuromyelitis optica (NMO). On the other hand, dysmyelination is a genetic or developmental abnormality of the myelin sheath seen in various leukodystrophies such as adrenal leukodystrophy and metachromatic leukodystrophy. A discussion of dysmyelinating diseases is beyond the scope of this chapter, which focuses on childhood demyelinating diseases of the CNS. In the last few years there has been increased interest in studying childhood-onset MS, and our understanding of acquired demyelinating disorders is increasing exponentially.