A very mild form of non-Herlitz junctional epidermolysis bullosa: BP180 rescue by outsplicing of mutated exon 30 coding for the COL15 domain.
Mutations in the gene COL17A1 cause non-Herlitz junctional epidermolysis bullosa. Here, we describe a patient who, despite two heterozygous mutations in COL17A1, has an extremely mild form of the disease missing most of the characteristic clinical features. DNA analysis revealed a frame-shift mutation 3432delT and a nonsense mutation 2356C-->T (Q751X). cDNA analysis showed that the deleterious effect of the latter mutation was skirted by deleting the premature termination codon containing exon 30. In this way, the reading frame was restored, resulting in a 36 nucleotides shorter mRNA transcript. Immunoblot analysis showed expression of the 180-kDa bullous pemphigoid antigen (BP180) with a slightly higher SDS-PAGE mobility, in line with the deletion of 12 amino acids from the COL15 domain. Immunofluorescence of skin sections showed diminished, but correctly localised expression of BP180, and this, in concert with the mild clinical phenotype, suggests that this COL15 mutated BP180 is still partly functional.
Centre for Blistering Diseases, Department of Dermatology, University Hospital Groningen, Groningen, The Netherlands.
A M G
AM
Pasmooij
S
S
van Zalen
A M
AM
Nijenhuis
A J
AJ
Kloosterhuis
J
J
Zuiderveen
M F
MF
Jonkman
H H
HH
Pas
D001324:Autoantigens / Q000235:genetics*; D001483:Base Sequence; D002352:Carrier Proteins; D003094:Collagen / Q000235:genetics*; D003598:Cytoskeletal Proteins; D000071821:Dystonin; D004820:Epidermolysis Bullosa / Q000145:classification / Q000235:genetics*; D005091:Exons; D016368:Frameshift Mutation / Q000235:genetics*; D006801:Humans; D009419:Nerve Tissue Proteins; D024041:Non-Fibrillar Collagens; D010391:Pemphigoid, Bullous / Q000145:classification / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics; D017384:Sequence Deletion; D012867:Skin / Q000473:pathology; D014158:Transcription, Genetic; D000097805:Collagen Type XVII
D001324:Autoantigens; D002352:Carrier Proteins; D003094:Collagen; D003598:Cytoskeletal Proteins; D000071821:Dystonin; D009419:Nerve Tissue Proteins; D024041:Non-Fibrillar Collagens; D012333:RNA, Messenger; D000097805:Collagen Type XVII; C486268:DST protein, human