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Monozygotic twin discordance for phacomatosis cesioflammea further supports the post‐zygotic mutation hypothesis
Author(s) -
Castori Marco,
Sarazani Stefano,
Binni Francesco,
Pezzella Francesca Romana,
Cruciani Giovanni,
Grammatico Paola
Publication year - 2011
Publication title -
american journal of medical genetics part a
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.064
H-Index - 112
eISSN - 1552-4833
pISSN - 1552-4825
DOI - 10.1002/ajmg.a.34140
Subject(s) - monozygotic twin , phenotype , mutation , microsatellite , biology , genetics , allele , gene
Phacomatosis pigmentovascularis (PPV) is a group of sporadic skin disorders combining widespread cutaneous capillary malformations and pigmented nevi. Etiopathogenesis of the various forms of PPV is unknown, although a non‐allelic twin spotting has been proposed as the most likely underlying mechanism. We report on the second instance of monozygotic twin discordance for PPV. Identical twins were observed shortly after birth, one affected by PPV and the other healthy, except for a standard Mongolian spot. Membrane examination was compatible with a monochorionic diamniotic pregnancy, and microsatellite analysis demonstrated monozygosity. This report confirms that PPV likely originates from a post‐zygotic mutation rising shortly after conception and affecting different cell lineages. Speculations about mechanisms linked to phenotypic discrepancies among identical twins were also put forward. © 2011 Wiley‐Liss, Inc.