Identification of the Genetic Mutation Responsible for Segmental Dysplastic Nevi
Dysplastic (atypical) melanocytic (DMN) nevi have been identified as being potential
precursors of melanoma and markers for patients at risk of developing primary melanoma1. In
addition, having an increased number of nevi is associated with increased risk1. DMN are
present in 2-5% of white adults in the U.S. population and international studies have
documented up to 18% prevalence2. These lesions may be present in at least 17% of white
adults with melanoma and 20-50% of melanomas may arise in nevi and atypical nevi2. The exact
gene(s) involved in the development of nevi have yet to be elucidated.
Segmental dysplastic nevi are nevi that are restricted to one area of the body3. This
condition is much rarer than the occurrence of dysplastic nevi, but nonetheless, may involve
the same genetic mutation. The pattern of distribution in SDN is thought to result from
mosaicism, i.e. the part of the body that expresses the dysplastic nevi has a mutation in a
gene, however, the rest of the body does not contain this same mutation. Other mosaic
disorders that have been studied in greater detail than SDN have been shown to be caused by
a single gene mutation4. It appears that SDN is no different and that it too is caused by a
mutation in a single gene, however, this gene is not yet known.
In this study we will perform a genetic analysis of tissue from a patient known to have SDN.
With the information we gather from this analysis, we may be able to find the gene
responsible for the development of dysplastic nevi.
Primary Research Objective:
To investigate the genetic mutation involved in the development of dysplastic nevi by
examining a patient with SDN.
Observational Model: Case-Only, Time Perspective: Prospective
Richard GB Langley, MD, FRCPC
Capital Health/Dalhousie University
Canada: Ethics Review Committee