Paradominant inheritance, a hypothesis explaining occasional familial occurrence of sporadic syndromes.
Heterozygous individuals carrying a "paradominant" mutation, as a rule, are phenotypically normal. Therefore, the mutation can be transmitted unperceived through many generations. The trait becomes manifest when a somatic mutation occurs during embryogenesis giving rise to loss of heterozygosity and forming a mutant cell population, being either homozygous or hemizygous for the mutation. This concept explains the occasional familial occurrence of usually sporadic traits like the Klippel-Trenaunay syndrome and others.
Department of Dermatology, University Hospital Nijmegen, Nijmegen, The Netherlands. p.steijlen@derma.azn.nl
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van Steensel
D005799:Genes, Dominant; D006801:Humans; D007715:Klippel-Trenaunay-Weber Syndrome / Q000235:genetics; D009506:Nevus / Q000150:complications / Q000235:genetics*; D012878:Skin Neoplasms / Q000150:complications / Q000235:genetics*; D013577:Syndrome