Loss of calcineurin Aalpha alters keratinocyte survival and differentiation.

Calcineurin is a serine/threonine phosphatase that is inhibited by the immunosuppressive drugs cyclosporine and FK506. Although calcineurin has been extensively studied in immune cells, less is known about calcineurin in other systems. There are two primary isoforms of the catalytic subunit of calcineurin, and mice have been created that lack either the alpha isoform (calcineurin A (CnA)alpha(-/-)) or the beta isoform (CnAbeta(-/-)). In this study, we examined the epidermis of CnAalpha(-/-) mice at birth and 4 weeks of age. Histological analyses revealed an attenuation of cells in the stratum spinosum of CnAalpha(-/-) mice. There was no significant difference in proliferation in the epidermis of CnAalpha(-/-) sections, but TUNEL assay revealed increased cell death in the supra-basal layers. Interestingly, the calcineurin substrate nuclear factor of activated T cells (NFATc) was highly expressed in the nucleus of basal epidermal cells in wild-type (WT) mice but was cytoplasmic in CnAalpha(-/-) mice, consistent with a loss of calcineurin activity. Moreover, NFATc activity was decreased in the epidermis of null mice compared with that in WT littermates. Finally, immunohistochemical staining revealed supra-basal expression of keratin 14 and decreased expression of differentiation-associated keratin 10 and involucrin. These findings suggest that calcineurin Aalpha activity is required for the normal differentiation and survival of epidermal cells.

Epidermolysis Bullosa Simplex with mottled pigmentation: mutation analysis in the first reported Hispanic pedigree with the largest single generation of affected individuals to date.

Epidermolysis bullosa simplex with mottled pigmentation (EBS-MP), characterized by trauma-induced blisters, distinct pigmentary changes of the trunk and extremities, and acral hyperkeratotic papules, is almost exclusively caused by a common KRT5 missense mutation affecting the V1 region of keratin 5. We studied the first Hispanic family, the largest single generation of affected family members in which 5 out of 10 siblings inherited EBS-MP from their affected father, as well a second large pedigree, the first reported of Finnish ancestry. In both families, the heterozygous transition mutation 74C-->T of the keratin 5 gene, which results in amino acid substitution P25L, completely co-segregated with the EBS-MP phenotype.

Bilateral anterior granulomatous uveitis associated with cutaneous Rosai-Dorfman disease.

BACKGROUND: Rosai-Dorfman disease (RDD) is a benign, rare, histiocytic disorder of unknown etiology. We describe the case of a 61-year-old woman who presented to the ophthalmology clinic with bilateral granulomatous anterior uveitis. METHODS: The uveitis was controlled on topical prednisolone acetate 1%. One month after presentation, she developed generalized macules and papules, and dermatologic and systemic evaluations were performed. RESULTS: On the basis of skin biopsy, purely cutaneous RDD was established. CONCLUSION: Anterior granulomatous uveitis may be the presenting sign of cutaneous RDD. Consultation is necessary for accurate diagnosis.