RESUMEN
Recessive dystrophic epidermolysis bullosa is a rare genodermatosis caused by a mutation of the Col7a1 gene. The Col7a1 gene codes for collagen type VII protein, a major component of anchoring fibrils. Mutations of the Col7a1 gene can cause aberrant collagen type VII formation, causing an associated lack or absence of anchoring fibrils. This presents clinically as chronic blistering, scarring, and fibrosis, often leading to the development of cutaneous squamous cell carcinoma. Patients also experience persistent pain and pruritus. Pain management and supportive bandaging remain the primary treatment options. The pathology of recessive dystrophic epidermolysis bullosa was first described in the 1980s, and there has since been a multitude of encouraging treatment options developed. However, in vivo research has been hindered by inadequate models of the disease. The various mouse models in existence possess longevity and surface area constraints, or do not adequately model a normal human disease state. In this paper, we describe a novel rat model of recessive dystrophic epidermolysis bullosa that offers an alternative to previous murine models. An 8-base pair deletion was induced in the Col7a1 gene of Lewis rats, which was subsequently found to cause a premature stop codon downstream. Homozygous mutants presented with a fragile and chronically blistered phenotype postnatally. Further histological analysis revealed subepidermal clefting and the absence of anchoring fibrils. The generation of this novel model offers researchers an easily maintained organism that possesses a larger surface area for experimental topical and transfused therapies to be tested, which may provide great utility in the future study of this debilitating disease.
Asunto(s)
Colágeno Tipo VII , Modelos Animales de Enfermedad , Epidermólisis Ampollosa Distrófica , Mutación del Sistema de Lectura , Fenotipo , Colágeno Tipo VII/genética , Animales , Epidermólisis Ampollosa Distrófica/genética , Epidermólisis Ampollosa Distrófica/patología , Ratas , Genes Recesivos , Ratas Endogámicas Lew , Vesícula/genética , Vesícula/patología , Piel/patología , MasculinoRESUMEN
In dystrophic epidermolysis bullosa the genetic defect of anchoring fibrils leads to cleavage beneath the basement membrane, with its consequent loss. We performed scanning electron microscopy of an inverted blister roof of a case of dystrophic epidermolysis bullosa, confirmed by immunomapping and gene sequencing. With a magnification of 2000 times a net attached to the blister roof could be easily identified. This net was composed of intertwined flat fibers. With higher magnifications, different fiber sizes could be observed, some thin fibers measuring around 80 nm and thicker ones measuring between 200 and 300 nm.
Na epidermólise bolhosa distrófica, o defeito genético das fibrilas ancorantes leva à clivagem abaixo da membrana basal, com sua consequente perda. Realizamos microscopia eletrônica de varredura do teto invertido de uma bolha de um caso de epidermólise bolhosa distrófica, cujo diagnóstico foi confirmado com imunomapeamento e com sequenciamento gênico. Com uma ampliação de 2.000 vezes, pôde ser facilmente identificada uma rede ligada ao teto da bolha. Essa rede era composta por fibras achatadas e entrelaçadas. Com grandes aumentos, fibras de diferentes tamanhos puderam ser observadas: algumas finas, medindo cerca de 80 nm, e outras mais largas, medindo entre 200 nm e 300 nm.
Asunto(s)
Humanos , Vesícula/patología , Epidermólisis Ampollosa Distrófica/patología , Membrana Basal , Vesícula/genética , Colágeno Tipo IV/ultraestructura , Colágeno Tipo VII/ultraestructura , Epidermólisis Ampollosa Distrófica/genética , Microscopía Electrónica de Rastreo , Piel/ultraestructuraRESUMEN
We report the case of a 28-year-old woman with Kindler syndrome, a rare form of epidermolysis bullosa. Clinically, since childhood, she had widespread pigmentary changes in her skin as well as photosensitivity and fragility of the skin and mucous membranes. The mucosal involvement led to an erosive stomatitis as well as esophageal, anal and vaginal stenoses, requiring surgical intervention. The diagnosis of Kindler syndrome was confirmed by DNA sequencing with compound heterozygosity for a nonsense/frameshift combination of mutations (p.Arg110X; p.Ala289GlyfsX7) in the FERMT1 gene.
Nós relatamos uma paciente feminina de 28 anos com Síndrome de Kindler, uma forma rara de Epidermólise Bolhosa. Clinicamente, ela apresentava alterações cutâneas pigmentares disseminadas, fotossensibilidade e fragilidade da pele e das mucosas desde a infância. O envolvimento mucoso levou à estomatite erosiva e a estenoses esofágica, anal e vaginal, as quais necessitaram de intervenções cirúrgicas. O diagnóstico de Síndrome de Kindler foi confirmado por sequenciamento de DNA, que demonstrou heterozigose composta uma combinação de mutações uma nonsense e outra frameshift (p.Arg110X; p.Ala289GlyfsX7) no gene FERMT1.