title: Molecular identification of collagen 17a1 as a major genetic modifier of laminin gamma 2 mutation-induced junctional epidermolysis bullosa in mice.
abstract: Epidermolysis Bullosa (EB) encompasses a spectrum of mechanobullous disorders caused by rare mutations that result in structural weakening of the skin and mucous membranes. While gene mutated and types of mutations present are broadly predictive of the range of disease to be expected, a remarkable amount of phenotypic variability remains unaccounted for in all but the most deleterious cases. This unexplained variance raises the possibility of genetic modifier effects. We tested this hypothesis using a mouse model that recapitulates a non-Herlitz form of junctional EB (JEB) owing to the hypomorphic jeb allele of laminin gamma 2 (Lamc2). By varying normally asymptomatic background genetics, we document the potent impact of genetic modifiers on the strength of dermal-epidermal adhesion and on the clinical severity of JEB in the context of the Lamc2(jeb) mutation. Through an unbiased genetic approach involving a combination of QTL mapping and positional cloning, we demonstrate that Col17a1 is a strong genetic modifier of the non-Herlitz JEB that develops in Lamc2(jeb) mice. This modifier is defined by variations in 1-3 neighboring amino acids in the non-collagenous 4 domain of the collagen XVII protein. These allelic variants alter the strength of dermal-epidermal adhesion in the context of the Lamc2(jeb) mutation and, consequentially, broadly impact the clinical severity of JEB. Overall the results provide an explanation for how normally innocuous allelic variants can act epistatically with a disease causing mutation to impact the severity of a rare, heritable mechanobullous disorder.
authors.affiliation: The Jackson Laboratory, Bar Harbor, Maine, United States of America.
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Sproule
authors.affiliation: The Jackson Laboratory, Bar Harbor, Maine, United States of America.
authors.forename: Jason A
authors.initials: JA
authors.lastname: Bubier
authors.affiliation: The Jackson Laboratory, Bar Harbor, Maine, United States of America.
authors.forename: Fiorella C
authors.initials: FC
authors.lastname: Grandi
authors.affiliation: The Jackson Laboratory, Bar Harbor, Maine, United States of America.
authors.forename: Victor Z
authors.initials: VZ
authors.lastname: Sun
authors.affiliation: The Jackson Laboratory, Bar Harbor, Maine, United States of America.
authors.forename: Vivek M
authors.initials: VM
authors.lastname: Philip
authors.affiliation: The Jackson Laboratory, Bar Harbor, Maine, United States of America.
authors.forename: Caroline G
authors.initials: CG
authors.lastname: McPhee
authors.affiliation: The Jackson Laboratory, Bar Harbor, Maine, United States of America ; Genetics Program, Sackler School of Graduate Biomedical Sciences, Tufts University, Boston, Massachusetts, United States of America.
authors.forename: Elisabeth B
authors.initials: EB
authors.lastname: Adkins
authors.affiliation: The Jackson Laboratory, Bar Harbor, Maine, United States of America.
authors.forename: John P
authors.initials: JP
authors.lastname: Sundberg
authors.affiliation: The Jackson Laboratory, Bar Harbor, Maine, United States of America.
authors.forename: Derry C
authors.initials: DC
authors.lastname: Roopenian
mesh_terms: D000818:Animals; D001324:Autoantigens / Q000235:genetics*; D004195:Disease Models, Animal; D016109:Epidermolysis Bullosa, Junctional / Q000209:etiology / Q000235:genetics* / Q000473:pathology; D004843:Epistasis, Genetic; D014644:Genetic Variation; D007797:Laminin / Q000235:genetics*; D051379:Mice; D009154:Mutation; D024041:Non-Fibrillar Collagens / Q000235:genetics*; D000097805:Collagen Type XVII
chemical_list: D001324:Autoantigens; D007797:Laminin; D024041:Non-Fibrillar Collagens; D000097805:Collagen Type XVII; C498522:Lamc2 protein, mouse