Asunto(s)
Alopecia/genética , Displasia Ectodérmica/genética , Hiperpigmentación/genética , Hipohidrosis/genética , Queratina-14/genética , Queratodermia Palmoplantar/genética , Enfermedades de la Uña/genética , Fenotipo , Neoplasias Cutáneas/genética , Alelos , Alopecia/diagnóstico , Alopecia/patología , Displasia Ectodérmica/diagnóstico , Displasia Ectodérmica/patología , Mutación del Sistema de Lectura , Humanos , Hiperpigmentación/diagnóstico , Hiperpigmentación/patología , Hipohidrosis/diagnóstico , Hipohidrosis/patología , Queratodermia Palmoplantar/diagnóstico , Queratodermia Palmoplantar/patología , Enfermedades de la Uña/diagnóstico , Enfermedades de la Uña/patología , Piel/patología , Neoplasias Cutáneas/diagnóstico , Neoplasias Cutáneas/patologíaRESUMEN
BACKGROUND: Epidermodysplasia verruciformis (EV) is a genodermatosis leading to infections with cutaneous HPV, persistent plane warts and a high rate of non-melanoma skin cancer (NMSC). Biallelic loss-of-function mutations in TMC6 and TMC8 are known to be causative. OBJECTIVE: The aim of this study was to report EV-causing mutations in four patients with EV and to give an overview of all described patients with EV. PATIENTS AND METHODS: We investigated four patients with classical features of EV from two families. All patients were affected by plane warts with typical EV histology since early childhood, and ß-HPVs were detected on their skin. One patient had recurring cutaneous squamous cell carcinomas (cSCC) and carcinomas in situ (Bowen type). We sequenced both TMC6/8 for disease-causing mutations and quantified levels of gene expression. We also performed a systematic literature review to discuss these patients in the context of previously reported cases, mutations already identified, as well as HPV types. RESULTS: Three patients of one family carried a homozygous splice site mutation in TMC8 resulting in aberrantly spliced transcripts that were not degraded. By contrast, no TMC6/8 mutation was detected in the patient from the other family. A systematic literature review revealed 501 described patients with EV. Around 40% of patients with EV analysed for genetic alterations carried no mutation in TMC6/8. While ß-HPVs were identified in the majority of cases, α-HPVs were detected in several individuals. CONCLUSION: The relatively high proportion of EV patients without mutation in TMC6/8 indicates the existence of EV-causing mutations in additional, presently unknown gene(s). However, a homozygous TMC8 splice site mutation in our patients resulted in aberrant transcripts which cannot retain the healthy phenotype. The literature review revealed that HPV-5 is the most commonly identified HPV in patients with EV, but HPV-3, HPV-14 and HPV-20 were unexpectedly identified more frequently than HPV-8.