A novel frameshift CYLD mutation in a family with multiple familial trichoepithelioma

Introduction: Multiple familial trichoepithelioma is a rare autosomal dominant genodermatosis caused by a mutation in the CYLD gene. This disease is characterized by the development of multiple skin-colored papules and nodules mainly on the central face. We herein describe a family with multiple familial trichoepithelioma with a novel frameshift mutation in CYLD. Case presentation: The proband was an 8-year-old girl who presented with a 2-year history of numerous progressive, asymptomatic, firm skin-colored papules on her nasal dorsum, nasolabial folds, and eyelids. Histopathological examination was compatible with the typical findings of trichoepithelioma. Her father displayed similar but inconspicuous smaller lesions on the face. Mutation analysis of the proband identified a heterozygous frameshift mutation c.1181_1182insCTTTGAC (p.D394fs) in exon 10 of CYLD. This mutation was also detected in the proband’s father, but not in either her mother or 100 unrelated control individuals Discussion: There is no obvious genotype–phenotype correlation in patients with multiple familial trichoepithelioma. In our study, the girl had a severe clinical appearance characterized by facial disfiguration, whereas her father had inconspicuous smaller lesions despite having the same mutation. We also identified a novel frameshift mutation c.1181_1182insCTTTGAC (p.D394fs) in exon 10 of the CYLD gene. The presence of this mutation leads to premature translation termination and thus to the synthesis of a truncated protein. Conclusion: We found a novel frameshift mutation of the CYLD gene in a Chinese family, thus expanding the database of CYLD gene mutations in multiple familial trichoepithelioma.