Monozygotic twins discordant for phacomatosis pigmentovascularis: evidence for the concept of twin spotting.

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.

• Authors: Tanya Moutray, Maria Napier, Ayad Shafiq, Alan Fryer, Simon Rankin, Colin E Willoughby
• Journal: American journal of medical genetics. Part A (Am J Med Genet A) Vol. 152A Issue 3 Pg. 718-20 (Mar 2010) ISSN: 1552-4833 [Electronic] United States
• PMID: 20186807 (Publication Type: Case Reports, Journal Article)
• Copyright: (c) 2010 Wiley-Liss, Inc.

Topics

• Diseases in Twins (etiology, genetics, pathology)
• Eye (blood supply, pathology)
• Female
• Humans
• Melanosis (genetics, pathology)
• Models, Genetic
• Mongolian Spot (genetics, pathology)
• Mosaicism
• Neurocutaneous Syndromes (etiology, genetics, pathology)
• Phenotype
• Pigmentation Disorders (genetics, pathology)
• Twins, Monozygotic
• Vascular Malformations (genetics, pathology)