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Insertion of mutant proteolipid protein results in missorting of myelin proteins
Author(s) -
VaursBarriere Catherine,
Wong Kondi,
Weibel Thais D.,
AbuAsab Mones,
Weiss Michael D.,
Kaneski Christine R.,
Mixon TongHui,
Bonavita Simona,
Creveaux Isabelle,
Heiss John D.,
Tsokos Maria,
Goldin Ehud,
Quarles Richard H.,
BoespflugTanguy Odile,
Schiffmann Raphael
Publication year - 2003
Publication title -
annals of neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.764
H-Index - 296
eISSN - 1531-8249
pISSN - 0364-5134
DOI - 10.1002/ana.10762
Subject(s) - proteolipid protein 1 , myelin , leukodystrophy , biology , transmembrane protein , myelin associated glycoprotein , axolemma , mutant , microbiology and biotechnology , pathology , genetics , myelin basic protein , medicine , gene , neuroscience , central nervous system , receptor , disease
Abstract Two brothers with a leukodystrophy, progressive spastic diplegia, and peripheral neuropathy were found to have proteinaceous aggregates in the peripheral nerve myelin sheath. The patients' mother had only subclinical peripheral neuropathy, but the maternal grandmother had adult‐onset leukodystrophy. Sequencing of the proteolipid protein (PLP) gene showed a point mutation IVS4 + 1 G→A within the donor splice site of intron 4. We identified one transcript with a deletion of exon 4 (Δex4, 169bp) encoding for PLP and DM20 proteins and lacking two transmembrane domains, and a second transcript with exon 4 + 10bp encoding three transmembrane domains. Immunohistochemistry showed abnormal aggregation in the myelin sheath of MBP and P0. Myelin‐associated glycoprotein was present in the Schmidt–Lanterman clefts but significantly reduced in the periaxonal region. Using immunogold electron microscopy, we demonstrated the presence of mutated PLP/DM20 and the absence of the intact protein in the patient peripheral myelin sheath. We conclude that insertion of mutant PLP/DM20 with resulting aberrant distribution of other myelin proteins in peripheral nerve may constitute an important mechanism of dysmyelination in disorders associated with PLP mutations. Ann Neurol 2003;54:769–780