Neuroblastoma in a pediatric patient with a microduplication of 2p involving the MYCN locus.

Neuroblastoma is the most common solid tumor of infancy, and mutations in several genes have been implicated as playing a role in tumor development. Here, we describe a pediatric patient with a constitutional microduplication of 2p24.3 who developed Stage 4 neuroblastoma at age 11 months. He represents the sixth patient described in the literature with partial trisomy 2p and neuroblastoma. All previous cases had duplication events spanning two genes implicated in neuroblastoma, MYCN and ALK. Our patient is unique because his duplicated region includes the MYCN gene only; the ALK gene is unaffected. These data, combined with the relatively high incidence of neuroblastoma reported in partial trisomy 2p patients, support the notion that MYCN duplication should be added to the growing list of genetic factors associated with an increased risk of neuroblastoma. The mechanism of increased risk is unclear, but the fact that our patient had dramatic amplification of MYCN in his tumor suggests that a germline duplication might predispose to further amplification. Additionally, our patient has several morphologic features common to patients with partial trisomy 2p including high forehead, hypertelorism, postaxial polydactyly, and developmental delay despite having a microduplication spanning approximately 1 Mb and including just three intact genes. This case may therefore help further delineate the genotype-phenotype correlations associated with partial trisomy 2p.