Meningioma in Down Syndrome

Area of Science:

• Genetics
• Oncology
• Neuropathology

Background:

• Down syndrome (DS) is a genetic disorder caused by trisomy 21.
• Epidemiological studies indicate a reduced incidence of solid tumors, including brain tumors, in individuals with DS.
• This protective effect is hypothesized to stem from tumor suppressor genes on the extra chromosome 21.

Observation:

• A case report details an 8-year-old boy with Down syndrome who developed an intracranial meningioma.
• Histological examination confirmed the meningioma diagnosis.
• Genetic analysis of the tumor revealed chromosome 21 heterogeneity, with cells exhibiting trisomy 21, disomy, and monosomy 21, while the patient's blood cells showed trisomy 21.

Findings:

• Fluorescence in situ hybridization confirmed high allele loss at the neurofibromin 2 gene locus, a common finding in meningiomas.
• The presence of both trisomy 21 and monosomy 21 in tumor cells suggests a loss of the extra chromosome 21 copy in some cells.
• This genetic instability involving chromosome 21 in the tumor is a novel observation.

Implications:

• The deletion of a chromosome 21 allele in the tumor may be linked to meningioma development in Down syndrome.
• This finding supports the hypothesis that genes on chromosome 21 act as tumor suppressors.
• Understanding these mechanisms could offer insights into cancer prevention and treatment strategies for individuals with Down syndrome.