has part has part characteristic of has modifier central nervous system myelination Morphological central nervous system abnormality Abnormal CNS myelination In the CNS, myelin is the product of oligodendrocytes (and not of Schwann cells, as in the PNS). This term refers to an abnormality of the process in which myelin sheaths are formed and maintained around neurons or the result of such an abnormality. Abnormal myelination abnormal process quality