Using population-based data to predict the impact of introducing noninvasive prenatal diagnosis for Down syndrome.

Purpose: To compare the number and types of chromosome abnormalities prenatally diagnosed and the number of invasive procedures between current prenatal testing pathways and a pathway where noninvasive prenatal diagnosis for Down syndrome replaces Down syndrome screening tests.

Methods: Numbers and types of chromosome abnormalities for each referral category were extracted from prenatal diagnostic testing reports routinely collected in Victoria, Australia, in 2006 and 2007. These data were then applied to the proposed implementation strategy.

Dysembryoplastic neuroepithelial tumor (DNT)-like oligodendrogliomas or Dnts evolving into oligodendrogliomas: two illustrative cases.

A review of dysembryoplastic neuroepithelial tumors (DNTs) in 14 patients over a 12-year period revealed four patients re-operated because of changes on magnetic resonance imaging (MRI) suggesting tumor recurrence or progression. In three of these, the histological features were identical to the initial DNT. In the fourth patient, persistent DNT was surrounded by WHO grade 2 oligoastrocytoma.

Quantitation of chromosome 1p and 19q deletions in glial tumours by interphase FISH on formalin-fixed paraffin-embedded tissue.

Deletions on chromosomes 1p and 19q identify oligodendroglial tumours that are likely to have a complete response to some chemotherapy regimens and are associated with prolonged patient survival. Detection of these chromosomal alterations is becoming increasingly important in the evaluation of glial tumours. Interphase fluorescence in situ hybridisation (FISH) is one of a number of techniques for detecting deletions, and is an efficient method for screening large numbers of tumours.

Isochromosome 5p mosaicism at prenatal diagnosis: observations and outcomes in six cases at chorionic villus sampling and one at amniocentesis.

We present six cases of 47,+i(5p)/46 mosaicism diagnosed at chorionic villus sampling (CVS), this being the first prospective series to be reported. The clinical indication in each was advanced maternal age. Further prenatal studies in four (amniocentesis, plus fetal blood sampling in one) did not show the isochromosome.