Metastatic medulloblastoma in an adolescent with Simpson-Golabi-Behmel syndrome.

We describe the case of a 12-year-old Hispanic male with a clinical and molecular diagnosis of Simpson-Golabi-Behmel Syndrome (SGBS) who subsequently developed metastatic medulloblastoma. While individuals with SGBS have been documented to have increased risk for intra-abdominal tumors such as Wilms tumor and neuroblastoma, medulloblastomas, or CNS tumors in general, have not been reported in patients with this syndrome. Our patient was clinically diagnosed with SGBS as an infant. He presented with many of the common features of the syndrome, such as cleft palate, macroglossia, post-axial polydactyly, "coarse" facial features, and ventricular septal defects (VSDs). Molecular testing performed in April 2009 confirmed the SGBS diagnosis. This testing detected a large intragenic deletion in the GPC3 gene (more than 500 kb, 8 exons) extending from intron 2, 37 kb downstream of exon 2, to the 5' end of the gene, deleting exons 1 and 2. However, subsequent testing by gene-centric high-density array comparative genomic hybridization (aCGH) detected a deletion encompassing only exon 2. Therefore, the exact 5' boundary of the deletion cannot currently be determined, due to an apparent complex rearrangement upstream of exon 1. We present this case of metastatic medulloblastoma as a unique malignancy in a patient with SGBS.