Recurrent Erythema Nodosum in a Child with a SHOC2 Gene Mutation.

We report the case of a 6-year-old male who developed recurrent erythema nodosum (EN) at the age of 3 years. The patient exhibited hypertelorism, low-set ears, micrognathia, moderate intellectual disability, thin long fingers, loose anagen hair, and prominent palmoplantar wrinkles. A heterozygous single nucleotide variant in the SHOC2 gene (c.4 A > G, p.S2G) was identified. Patients with a SHOC2 mutation exhibit a unique combination of ectodermal abnormalities including darkly pigmented skin and loose anagen hair. This report is the first to describe EN in a patient with SHOC2 mutation, and to examine the patient's hair using scanning electron microscopy. We hypothesize that the RAS/MAPK pathway is associated with the pathogenesis of cutaneous lesions in patients with SHOC2 mutations via autoinflammation and disturbance of epithelial stem cells.