A light and electron microscopic study showing altered keratin expression in ichthyosis hystrix curth-macklin
✍ Scribed by Lasse Kanerva; Kirsti-Maria Niemi; Ismo Virtanen
- Book ID
- 103915773
- Publisher
- Elsevier Science
- Year
- 1990
- Tongue
- English
- Weight
- 202 KB
- Volume
- 21
- Category
- Article
- ISSN
- 0739-6260
No coin nor oath required. For personal study only.
✦ Synopsis
Recessive ichthyosis congenita (IC) is a very rare disease. However, electron microscopic examinations have revealed at least five types of recessive IC. Here, 36 recessive IC patients were examined and nine patients from seven families had cholesterol crystals in the corneocytes. These were first demonstrated by us and are, currently, considered diagnostic for IC type II. Each of the nine patients was born as a collodion baby and all developed hyperkeratotic palms and soles, severe ectropium and had involved flexures. Partial alopecia was present in four and mild erythrodermia in six. Currently, eight patients are on etretinate therapy with a moderate to good response. Light and electron microscopy was performed in all cases. Light microscopy showed a thickened horny and malpighian layer. Follicles were short and distorted, and contained keratin plugs. Electron microscopy showed that cholesterol crystals were present in all patients, but not in every section. The crystals were often aggregated in groups and appeared as electron-negative rods. In some areas the crystals nearly filled the corneocytes which also contained moderate to high numbers oflipid droplets. Keratinosome 'ghosts' were regularly seen in the corneocytes, which were tightly glued together with intercellular substance. The marginal bands were thin or absent in eight patients but normal in one. Keratohyalin granules were small and stellate and observed in up to seven layers. The lower epidermis and upper dermis did not show any pathognomonic features. This is the first report where clinical and electron microscopic features of IC type II have been combined. The pedigree of our patients indicated recessive inheritance. The cholesterol crystals indicated a lipid metabolism disorder and the defective corneocyte envelope could indicate a structural protein abnormality.