G2Cdb::Allele report

Mutation type
Du

Altered genes (1)

Gene Symbol Species Description
G00001806 PLP1 Homo sapiens proteolipid protein 1

Diseases (1)

Disease Description Nervous effect
D00000155 Pelizaeus-Merzbacher disease Y

Literature (1)

Pubmed - other

  • Heterogeneous duplications in patients with Pelizaeus-Merzbacher disease suggest a mechanism of coupled homologous and nonhomologous recombination.

    Woodward KJ, Cundall M, Sperle K, Sistermans EA, Ross M, Howell G, Gribble SM, Burford DC, Carter NP, Hobson DL, Garbern JY, Kamholz J, Heng H, Hodes ME, Malcolm S and Hobson GM

    Clinical and Molecular Genetics, Institute of Child Health, London.

    We describe genomic structures of 59 X-chromosome segmental duplications that include the proteolipid protein 1 gene (PLP1) in patients with Pelizaeus-Merzbacher disease. We provide the first report of 13 junction sequences, which gives insight into underlying mechanisms. Although proximal breakpoints were highly variable, distal breakpoints tended to cluster around low-copy repeats (LCRs) (50% of distal breakpoints), and each duplication event appeared to be unique (100 kb to 4.6 Mb in size). Sequence analysis of the junctions revealed no large homologous regions between proximal and distal breakpoints. Most junctions had microhomology of 1-6 bases, and one had a 2-base insertion. Boundaries between single-copy and duplicated DNA were identical to the reference genomic sequence in all patients investigated. Taken together, these data suggest that the tandem duplications are formed by a coupled homologous and nonhomologous recombination mechanism. We suggest repair of a double-stranded break (DSB) by one-sided homologous strand invasion of a sister chromatid, followed by DNA synthesis and nonhomologous end joining with the other end of the break. This is in contrast to other genomic disorders that have recurrent rearrangements formed by nonallelic homologous recombination between LCRs. Interspersed repetitive elements (Alu elements, long interspersed nuclear elements, and long terminal repeats) were found at 18 of the 26 breakpoint sequences studied. No specific motif that may predispose to DSBs was revealed, but single or alternating tracts of purines and pyrimidines that may cause secondary structures were common. Analysis of the 2-Mb region susceptible to duplications identified proximal-specific repeats and distal LCRs in addition to the previously reported ones, suggesting that the unique genomic architecture may have a role in nonrecurrent rearrangements by promoting instability.

    Funded by: NCRR NIH HHS: P20 RR-020173-01, P20 RR020173; NINDS NIH HHS: NS043783, R01 NS043783; Wellcome Trust

    American journal of human genetics 2005;77;6;966-87

© G2C 2014. The Genes to Cognition Programme received funding from The Wellcome Trust and the EU FP7 Framework Programmes:
EUROSPIN (FP7-HEALTH-241498), SynSys (FP7-HEALTH-242167) and GENCODYS (FP7-HEALTH-241995).

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