Familial progressive hyperpigmentation: A family resurvey and ultrastructural skin investigation.

Familial progressive hyperpigmentation (FPH) is an autosomal dominant genodermatosis characterized by hyperpigmented patches that increase in size and number with age. Since its initial description in an African-American family in 1971, only a few cases of FPH have been documented. A three-generation family with FPH in central China has also been reported. Here, we resurveyed that Chinese FPH family for a few unusual features including delayed age of onset and noninvolvement of ocular and oral mucosae. Electron microscopic examination of skin from the proband of the family showed that there were more melanosomes in lesional keratinocytes than in perilesional keratinocytes. Additionally, a large number of nonmembrane-bound melanosome complexes were observed in the keratinocytes of hyperpigmented areas, whereas all of the melanosomes were dispersed in the keratinocytes of normally pigmented areas.