X-linked reticulate pigmentary layer. Report of a new patient and demonstration of a skewed X-inactivation.

We report a boy, born to healthy first cousin parents, with diffuse hyperpigmentation of the skin and guttate hypomelanotic lesions, photophobia, abnormal hair, developmental delay, and recurrent bronchitis. Skin histology showed pigmentation incontinence with numerous melanophages. Electron microscopy showed a very high number of melanosomes and some degenerating keratinocytes. These features correspond to a rare genodermatosis, the X-linked reticulate pigmentary disorder with systemic manifestations. Skewed X-inactivation patterns were detected in the mother's lymphocytes.