Identification of LCK mutation in a family with atypical epidermodysplasia verruciformis with T-cell defects and virus-induced squamous cell carcinoma.

BACKGROUND: Inherited epidermodysplasia verruciformis (EV) is a rare skin disorder characterized by susceptibility to specific types of human papilloma virus (HPV) and is strongly associated with skin carcinomas. Inactivating mutations in EVER1/EVER2 account for most cases of EV. However, more phenotypes related to but distinct from EV have been reported with an immunodeficiency state but without EVER1/EVER2 mutation, and the genetic basis for these atypical EV cases is poorly understood.

OBJECTIVES: To identify the causative gene responsible for three siblings affected by atypical EV but without EVER1/EVER2 mutation.

METHODS: Whole-exome sequencing followed by Sanger sequencing was performed to identify the gene responsible for the patients with atypical EV enrolled in our study.

RESULTS: A homozygous splicing mutation was detected in LCK (c.188-2A>G). This mutation resulted in an exon 3 deletion T lymphocyte-specific protein tyrosine kinase isoform, which further led to frameshift mutation and subsequent mRNA decay.

CONCLUSIONS: We demonstrate a novel mutation in LCK in a family affected by atypical EV with T-cell defects, HPV infection and virus-induced malignancy, providing new clues in the understanding of host defences against HPV and better genetic counselling of patients with the EV phenotype.