Reticular erythrokeratoderma: a new disorder of cornification.

Heritable disorders of cornification form a large, clinically and genetically heterogeneous group. Recent advances in molecular genetics provide for the first time the opportunity to reliably classify some of these disorders based on their underlying etiology. Many rare phenotypes, however, still remain unclassified and do not fit into established classification schemes. We report here a 12-year-old girl who developed an ichthyosis vulgaris-like skin disorder 6 months after birth. Several years later, the clinical features had changed considerably. The patient had developed streaks of hyperkeratotic, slightly scaling skin with underlying erythema distributed in a reticulate, occasionally annular pattern on the trunk and extremities. The lesions were stable and had not changed significantly in size or distribution over the ensuing years. Histopathologic and ultrastructural findings were nonspecific and there was no evidence for metabolic disorders. The partial clinical overlap with erythrokeratodermia variabilis prompted us to screen several connexin genes but no pathogenic mutations were identified. We believe that this disorder belongs to the group of erythrokeratodermas and represents a novel, previously unrecognized entity.