De Novo COL7A1 mutation in a patient with trisomy 21: coexistence of dystrophic epidermolysis bullosa and Down syndrome.

[dystrophic epidermolysis bullosa]

Down syndrome (DS ) is the most common autosomal chromosomal disorder . Epidermolysis bullosa (EB ) is a rare genodermatosis characterized by skin and mucous membrane fragility , with formation of blisters and erosions after minor trauma . Dystrophic EB (DEB ) is inherited as an autosomal dominant (DDEB ) or recessive (RDEB ) trait . Both forms are caused by mutations in COL 7 A 1 , the gene coding for the type VII collagen . We report a patient affected by both conditions : DS and DDEB .A patient with DS developed generalized blisters at the age of three months . Cytogenetic study was performed to confirm DS . Skin biopsies were examined with immunohistochemical and electron microscopy techniques to determine EB subtype . Genomic DNA was extracted from peripheral blood samples . COL 7 A 1 mutations were screened by heteroduplex analysis using conformation-sensitive gel electrophoresis and sequencing .Karyotype analysis revealed trisomy 21 . Histological study agreed with a DEB diagnosis . Mutational analysis showed a heterozygous c .6127 G >T mutation in COL 7 A 1 , which is compatible with DDEB . Parental study suggests that c .6127 G >T arises as a de novo mutation .This report demonstrates that EB can be associated with other common conditions and reports the case of a patient who suffered two de novo independent genetic conditions . It also contributes to expanding the knowledge and database of clinical and molecular aspects of DDEB .