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Monozygotic twins discordant for phacomatosis pigmentovascularis: Evidence for the concept of twin spotting
Author(s) -
Moutray Tanya,
Napier Maria,
Shafiq Ayad,
Fryer Alan,
Rankin Simon,
Willoughby Colin E.
Publication year - 2010
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.33232
Subject(s) - monozygotic twin , iris (biosensor) , dermatology , medicine , biology , genetics , computer security , computer science , biometrics
Abstract The term phacomatosis pigmentovascularis (PPV) refers to the occurrence of vascular nevi with melanocytic or epidermal nevi. We report on monozygotic twins (MZTs) discordant for phacomatosis cesioflammea (PPV type II) providing evidence for the mechanism of twin spotting in the development of PPV. The affected twin had a nevus flammeus on the right arm and the right maxilla, and a pigmented area on the trunk in keeping with a persistent, aberrant Mongolian spot. The affected twin had bilateral ocular melanocytosis with abnormal scleral pigmentation, iris mamillations, increased pigmentation of the trabecular meshwork, and increased fundal pigmentation and secondary glaucoma. DNA testing confirmed monozygosity. This case of MZTs discordant for PPV supports the hypothesis that PPV results from mosaicism due to a post‐zygotic mutational event and the concept of twin spotting. © 2010 Wiley‐Liss, Inc.