DefinitionThis section has been translated automatically.
In the biological sense, an organism composed of genetically diverse cells that have emerged from a homogeneous zygote is called a mosaic. In contrast, a chimera arises from different cell populations. Cutaneous mosaics can be divided into 2 categories:
- Epigenetic mosaics: All cells have the same genome. Functionally different cell clones arise due to the influence of certain control genes. These functional mosaics are hereditary.
- Genetic mosaics: Two or more cell populations have different genomes.
Acquired mosaic dermatoses: Some acquired skin diseases, usually diffusely distributed, may appear "suddenly" (in a phase of exacerbation) along Blaschko lines (in atopic eczema, psoriasis vulgaris, dyskeratosis follicularis, lichen planus, circumskripter scleroderma, and others). The cause is probably a mutated cell clone acting as a "locus minoris resistentiae" in which the underlying disease is realized.
Clinical pictureThis section has been translated automatically.
Mosaics are particularly easy to identify in the skin, as the different cell systems are often visibly morphologically distinct from each other. Very diverse mosaic patterns can be distinguished in the skin:
- Type I: Skin manifestations along the Blaschko lines(ILVEN, Incontinentia pigmenti achromians (Ito); Incontinentia pigmenti, Bloch-Sulzberger type).
- Type II: Checkerboard pattern(nevus spilus, Becker nevus).
- Type III: Phylloid pattern(phylloid hypomelanosis).
- Type IV: Patchy pattern without midline border(melanocytic giant nevi).
- Type V: Lateralization pattern(CHILD syndrome).
- Twin spots: closely adjacent occurrence of two malformations in one and the same patient.
LiteratureThis section has been translated automatically.
- Happle R (2004) Cutaneous mosaics: patterns and molecular mechanisms. Dt Ärzteblatt 101: 1575-1580.
- Happle R (2016) The categories of cutaneous mosaicism: a proposed classification. Am J Med Genet A 170A: 452-459.
- Moog U et al (2020) Diseases caused by genetic mosaicism. Dtsch Ärztebl Int 117: 119-125.
- Peron A et al (2018) Genetics, genomics, and genotype-phenotype correlations of TSC: insights for clinical practice. Am J Med Genet C Semin Med Genet 178: 281-290.
- Rohlin A et al. (2009) Parallel sequencing used in detection of mosaic mutations: comparison with four diagnostic DNA screening techniques. Hum Mutat 30: 1012-1020