## 1 Introduction  
Recessive dystrophic epidermolysis bullosa (RDEB) is a very infrequent, aggressive subtype of dystrophic epidermolysis bullosa (DEB), a hereditary ailment starting right from birth in the form of trauma-induced blistering and scare formation of the skin. This disease prevails consequently due to biallelic genetic mutations in the _COL7A1_ gene, which is responsible for collagen type VII (C7) production. Due to these mutations, C7 becomes absent or shows various anomalies in structure leading to disruptions in anchoring fibrils, which are the main securing bodies of the skin's dermal and epidermal layers [1]. As a result of these mutations, the dermal layer of the affected individuals is always exposed to blister formations with minor trauma. RDEB is divided into numerous subtypes: severe form, an intermediate form and, other, rare, subtypes which include localized, prurginosa and inversa [2]. Cutaneous manifestations of the RDEB include blister formation and development of wounds as a result of minor mechanical traumas, atrophic scarring and milia creation, nails dystrophy, and alopecia. Pruritus is also a frequent complaint. The individuals affected with severe and intermediate RDEB are more prone to develop squamous cell carcinoma (SCC) due to chronic wound formation and fibrosis which result in early death and reduced life expectancy in those patients [2; 3]. Pseudos Syndactyly, growth retardation, dental caries, anemia, esophageal strictures, malnourishment, and visual manifestations are some of the extracutaneous symptoms [1]. There are currently no authorized RDEB disease-modifying treatments. The disease's therapy is confined to symptom management and secondary complications such wound care, trauma prevention, infection treatment, pain and itch management, strategically wrapping of the feet and hands to avoid pseudosynadactyly, and early diagnosis and treatment of SCC [1; 4; 5]. The disease's gastrointestinal manifestations are handled with nutritional support, such as gastrostomy feeding, dilatation of an esophagus, and curing anemia [1; 5]. Physiotherapy and rehabilitation, psychological and social provisions, and extra educational campaigns are all elements of disease management [1; 4; 6].  
The most definitive tests for genetic analysis are a combination of gene-targeted testing (concurrent or, multigene panel, serial single-gene testing or single-gene testing), or more inclusive genomic testing (whole genome sequencing, chromosomal microarray analysis, or exome sequencing) based on the phenotype, but direct immunofluorescence (IF) and/or transmission electron microscopy (EM) may be useful, especially in the classification of its subforms [7].  
In the present study, the WES method was applied for the mutational analysis of EB- affected patients in three families from three different provinces of Pakistan. A comprehensive clinical investigation followed by WES identified a novel biallelic missense mutation c.7034G>A, p. Gly2345 Asp in exon 91, a novel frameshift mutation c.385 del (p. His129 MetfsTer18) in homozygous form in exon no 3 and a known homozygous nonsense mutation c.1573 C>T (p. R525*) in exon no 12 of the _COL7A1_ gene.