TY - JOUR
T1 - Revertant mosaicism
T2 - Partial correction of a germ-line mutation in COL17A1 by a frame-restoring mutation
AU - Darling, Thomas N.
AU - Yee, Carole
AU - Bauer, Johann W.
AU - Hintner, Helmut
AU - Yancey, Kim B.
PY - 1999/5
Y1 - 1999/5
N2 - Generalized atrophic benign epidermolysis bullosa is an autosomal recessive subepidermal blistering disease typified by null mutations in COL17A1. In 1 large kindred, affected individuals were homozygous for a 2-bp deletion in COL17A1, 4003delTC, which resulted in a downstream premature termination codon, nonsense-mediated mRNA decay, and abrogation of type XVII collagen synthesis. Interestingly, 1 of these patients, although phenotypically identical to her affected siblings showed focal expression of type XVII collagen in epidermal basement membrane in a pattern suggestive of revertant mosaicism. When studies of randomly obtained epidermal, oromucosal, and peripheral blood cells failed to identify the genetic basis of this apparent mosaicism, microscopic subpopulations of potentially revertant epidermal cells (i.e., those overlying basement membrane containing type XVII collagen) were selectively isolated using laser capture microdissection. Analysis of DNA and RNA from these cells revealed a second mutation, 4080insGG, on 1 allele of COL17A1. This 2-bp insertion corrected the reading frame just proximal to the premature termination codon, countered nonsense- mediated mRNA decay, and allowed protein production by patient keratinocytes in vivo and in vitro. These studies elucidate the molecular basis of a novel form of revertant mosaicism in humans.
AB - Generalized atrophic benign epidermolysis bullosa is an autosomal recessive subepidermal blistering disease typified by null mutations in COL17A1. In 1 large kindred, affected individuals were homozygous for a 2-bp deletion in COL17A1, 4003delTC, which resulted in a downstream premature termination codon, nonsense-mediated mRNA decay, and abrogation of type XVII collagen synthesis. Interestingly, 1 of these patients, although phenotypically identical to her affected siblings showed focal expression of type XVII collagen in epidermal basement membrane in a pattern suggestive of revertant mosaicism. When studies of randomly obtained epidermal, oromucosal, and peripheral blood cells failed to identify the genetic basis of this apparent mosaicism, microscopic subpopulations of potentially revertant epidermal cells (i.e., those overlying basement membrane containing type XVII collagen) were selectively isolated using laser capture microdissection. Analysis of DNA and RNA from these cells revealed a second mutation, 4080insGG, on 1 allele of COL17A1. This 2-bp insertion corrected the reading frame just proximal to the premature termination codon, countered nonsense- mediated mRNA decay, and allowed protein production by patient keratinocytes in vivo and in vitro. These studies elucidate the molecular basis of a novel form of revertant mosaicism in humans.
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U2 - 10.1172/JCI4338
DO - 10.1172/JCI4338
M3 - Article
C2 - 10330419
AN - SCOPUS:0032740890
SN - 0021-9738
VL - 103
SP - 1371
EP - 1377
JO - Journal of Clinical Investigation
JF - Journal of Clinical Investigation
IS - 10
ER -