Genotype-phenotype correlation in Junctional Epidermolysis Bullosa:signposts to severity

Junctional epidermolysis bullosa (JEB) is a rare autosomal recessive genodermatosis with a broad spectrum of phenotypes. Current genotype-phenotype paradigms are insufficient to accurately predict JEB subtype and characteristics from genotype, particularly for splice site mutations, which account for over a fifth of disease-causing mutations in JEB. This study evaluated genetic and clinical findings from a JEB cohort, investigating genotype-phenotype correlations through bioinformatic analyses and comparison with previously reported mutations.Eighteen unique mutations in LAMB3, LAMA3, LAMC2 or COL17A1 were identified from seventeen individuals. Seven had severe JEB, nine intermediate JEB and one laryngo-onycho-cutaneous syndrome. Seven mutations were previously unreported. Deep phenotyping was completed for all intermediate JEB cases and demonstrated substantial variation between individuals. Splice site mutations underwent analysis with SpliceAI, a state-of-the-art artificial intelligence tool, in order to predict resultant transcripts. Predicted functional effects included exon skipping and cryptic splice site activation, which provided potential explanations for disease severity and in most cases correlated with lamimin-332 immunofluorescence. RT-PCR was performed for one case to investigate resultant transcripts produced from the splice site mutation.This study expands the JEB genomic and phenotypic landscape. AI tools show potential for predicting functional effects of splice site mutations and may identify candidates for confirmatory laboratory investigation. Investigation of RNA transcripts will help to further elucidate genotype-phenotype correlations for novel mutations

Mutations in <em>GRHL2</em> result in an autosomal-recessive ectodermal dysplasia syndrome

Grainyhead-like 2, encoded by GRHL2, is a member of a highly conserved family of transcription factors that play essential roles during epithelial development. Haploinsufficiency for GRHL2 has been implicated in autosomal-dominant deafness, but mutations have not yet been associated with any skin pathology. We investigated two unrelated Kuwaiti families in which a total of six individuals have had lifelong ectodermal defects. The clinical features comprised nail dystrophy or nail loss, marginal palmoplantar keratoderma, hypodontia, enamel hypoplasia, oral hyperpigmentation, and dysphagia. In addition, three individuals had sensorineural deafness, and three had bronchial asthma. Taken together, the features were consistent with an unusual autosomal-recessive ectodermal dysplasia syndrome. Because of consanguinity in both families, we used whole-exome sequencing to search for novel homozygous DNA variants and found GRHL2 mutations common to both families: affected subjects in one family were homozygous for c.1192T>C (p.Tyr398His) in exon 9, and subjects in the other family were homozygous for c.1445T>A (p.Ile482Lys) in exon 11. Immortalized keratinocytes (p.Ile482Lys) showed altered cell morphology, impaired tight junctions, adhesion defects, and cytoplasmic translocation of GRHL2. Whole-skin transcriptomic analysis (p.Ile482Lys) disclosed changes in genes implicated in networks of cell-cell and cell-matrix adhesion. Our clinical findings of an autosomal-recessive ectodermal dysplasia syndrome provide insight into the role of GRHL2 in skin development, homeostasis, and human disease

Genotypic and phenotypic characterisation of HIV-2 viruses from CA10, Guinea Bissau : determining association with disease progression

EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Desquamative enteropathy and pyloric atresia without skin disease caused by a novel intracellular beta4 integrin mutation

ITGB4 mutation may induce a desquamative enteropathy in infancy without significant skin disease. A history of pyloric atresia is important in infants with severe chronic diarrhoeal disease and should prompt investigation for JEB-PA associated mutations. Acquired immune responses may exacerbate primary genetic disorders of epithelial adhesion and immunomodulatory therapy may be beneficial

A Homozygous Nonsense Mutation within the Dystonin Gene Coding for the Coiled-Coil Domain of the Epithelial Isoform of BPAG1 Underlies a New Subtype of Autosomal Recessive Epidermolysis Bullosa Simplex

Epidermolysis bullosa (EB) is a group of autosomal dominant and recessive blistering skin diseases in which pathogenic mutations have been reported in 13 different genes encoding structural proteins involved in keratinocyte integrity, as well as cell–matrix or cell–cell adhesion. We now report an inherited skin fragility disorder with a homozygous nonsense mutation in the dystonin gene (DST) that encodes the coiled-coil domain of the epithelial isoform of bullous pemphigoid antigen 1, BPAG1-e (also known as BP230). The mutation, p.Gln1124X, leads to the loss of hemidesmosomal inner plaques and a complete absence of skin immunostaining for BPAG1-e, as well as reduced labeling for plectin, the β4 integrin subunit, and for type XVII collagen. The 38-year-old affected individual has lifelong generalized trauma-induced spontaneous blisters and erosions, particularly around the ankles. In addition, he experiences episodic numbness in his limbs, which started at the age of 37 years. These neurological symptoms may also be due to DST gene mutation, although he has a concomitant diagnosis of CADASIL (cerebral arteriopathy, autosomal dominant, with subcortical infarcts and leukoencephalopathy), a cerebral small-vessel arteriopathy, which thus complicates the genotype–phenotype interpretation. With regard to skin blistering, the clinicopathological findings expand the molecular basis of EB by identifying BPAG1-e pathology in a new form of autosomal recessive EB simplex