Prenatal Diagnosis for Recessive Dystrophic Epidermolysis Bullosa in 10 Families by Mutation and Haplotype Analysis in the Type VII Collagen Gene (COL7A1)

Abstract

Background: Epidermolysis bullosa (EB) is a group of heritable diseases that manifest as blistering and erosions of the skin and mucous membranes. In the dystrophic forms of EB (DEB), the diagnostic hallmark is abnormalities in the anchoring fibrils, attachment structures beneath the cutaneous basement membrane zone. The major component of anchoring fibrils is type VII collagen, and DEB has been linked to the type VII collagen gene (COL7A1) at 3p21, with no evidence for locus heterogeneity. Due to life-threatening complications and significant long-term morbidity associated with the severe, mutilating form of recessive dystrophic EB (RDEB), there has been a demand for prenatal diagnosis from families with affected offspring. Materials and Methods: Intragenic polymorphisms in COL7A1 and flanking microsatellite markers on chromosome 3p2 1, as well as detection of pathogenetic mutations in families, were used to perform PCR-based prenatal diagnosis from DNA obtained by chorionic villus sampling at 10-15 weeks or amniocentesis at 12-15 weeks gestation in 10 families at risk for recurrence of RDEB. Results: In nine cases, the fetus was predicted to be normal or a clinically unaffected carrier of a mutation in one allele. These predictions have been validated in nine cases by the birth of a healthy child. In one case, an affected fetus was predicted, and the diagnosis was confirmed by fetal skin biopsy. Conclusions: DNA-based prenatal diagnosis of RDEB offers an early, expedient method of testing which will largely replace the previously available invasive fetal skin biopsy at 18-20 weeks gestation.

Epidermolysis bullosa. II. Type VII collagen mutations and phenotype-genotype correlations in the dystrophic subtypes

“…In the British population, three recurrent PTC-causing mutations have been described: R578X, 7786delG and R2814X. 25 26 32-34 R578X and R2814X were also seen in our study, mainly in patients of European ancestry, although one Hispanic patient exhibited the R2814X mutation. Three mutations, 5818delC, 6573+1 GRC and E2857X, have been detected only in Japanese patients with RDEB; all were seen in our patients as well, with 5818delC and 6573+1 GRC detected in Japanese patients and E2857X found in one Korean family.…”

“…[23][24][25][26][27][28] Four of these mutations were previously undescribed, whereas the rest have been reported in the literature. These recurrent mutations in our cohort were not restricted to any particular ethnic background, although the mutation 425ARG was seen mainly in patients of European ancestry.…”

Novel and recurrent COL7A1 mutations in Chilean patients with dystrophic epidermolysis bullosa

“…In order to establish the cause of the recurrence of c.6527dupC and c.7708delG we performed haplotype analysis for 16 and 11 carrier families, respectively. One intragenic single nucleotide polymorphism (c.2820G/A) and three informative microsatellite markers (D3S1581, D3S1289 and D3S1029) in linkage with the COL7A1 locus were studied [7,8]. Results showed that c.6527dupC segregated with a single haplotype, demonstrating a common ancestral origin.…”

Three homozygous PTC mutations in the collagen type VII gene of patients affected by recessive dystrophic epidermolysis bullosa: Analysis of transcript levels in dermal fibroblasts

“…The following intragenic polymorphic sites of COL7A1 were analyzed: the AluI site in exon 14, the PvuII site in exon 21, and the MspI site in exon 30 [Christiano et al, 1994b]. Genotyping for the D3S1235, D3S1573, D3S1581, and D3S1076 microsatellites markers linked to COL7A1 was performed by fluorescent PCR analysis in the automatic sequencer, using the primers and the amplification conditions reported by Christiano et al [1996c].…”