Histologic and ultrastructural features of the ichthyotic skin in X-linked dominant chondrodysplasia punctata.

The ichthyotic skin in X-linked dominant chondrodysplasia punctata was investigated in a four-week-old baby and a fourteen-year-old girl. Histologically, the ichthyosiform erythroderma of the newborn and the ichthyosis of the older child presented as a retention hyperkeratosis with several distinctive features such as calcification of the keratotic follicular plugs, atrophy of the hair follicles and focal hyperpigmentation of the basal keratinocytes. On ultrastructural examination, small to medium sized vacuoles were regularly seen in the thinned granular layer. Some of these vacuoles contained needle-like calcium inclusions. The histologic and ultrastructural findings are therefore characteristic for this rare type of ichthyosis.