Uncompacted myelin lamellae in peripheral nerve biopsy.
Ultrastructural Pathology. 2003-01-01; 27(1): 1-5
DOI: 10.1080/01913120309941
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Since 1979, the authors have studied 49 peripheral nerve biopsies presenting
uncompacted myelin lamellae (UML). Based on the ultrastructural pattern of UML
they propose a 3-category classification. The first category includes cases
displaying regular UML, which was observed in 43 cases; it was more frequent in 9
cases with polyneuropathy organomegaly endocrinopathy m-protein skin changes
(POEMS) syndrome as well as in 1 case of Charcot-Marie-Tooth 1B with a novel
point mutation in the P0 gene. The second category consists of cases showing
irregular UML, observed in 4 cases with IgM monoclonal gammopathy and
anti-myelin-associated glycoprotein (MAG) activity. This group included 1 benign
case and 3 B-cell malignant lymphomas. The third category is complex UML, which
was present in 2 unrelated patients with an Arg 98 His missense mutation in the
P0 protein gene. Irregular and complex UML are respectively related to MAG and
P0, which play a crucial role in myelin lamellae compaction and adhesion.