Familial anaplastic ependymoma: evidence of loss of chromosome 22 in tumour cells.

A family with anaplastic ependymomas, histologically verified in three cases and neuroradiologically suggested in a fourth, is presented. Two healthy brothers both had two affected sons. All four male patients were younger than 5 years at the time of diagnosis. Two boys died before the age of 3 years. Genotype analysis (with polymorphic DNA markers for chromosome 22 and interphase cytogenetic analysis) of one of the tumours showed a subpopulation of tumour cells with monosomy of (part of) chromosome 22. Non-neoplastic cells of this patient showed a normal karyotype. These findings give further evidence for the role of a tumour suppressor gene on chromosome 22 in the pathogenesis of familial ependymal tumours.