Prenatal Genetic Testing

Common indications for prenatal genetic testing:

• Advanced maternal age
• Abnormal maternal serum screens
• Family history/carrier of inherited disease or chromosome rearrangement
• Fetal abnormality detected through ultrasound
• Family history of chromosome abnormality
• Previous child with an inherited disease, neural tube defect, or chromosome abnormality.

This laboratory provides cytogenetic analysis on the following:

Amniocentesis - Amniotic fluid obtained between the 13th and 24th week of pregnancy can be tested for chromosome abnormalities.

Chorionic Villi Sampling - Chorionic villi obtained through CVS procedure between the 10th and 12th week of pregnancy can be tested for chromosome abnormalities.

Percutaneous Umbilical Blood Sampling (PUBS) - Fetal blood obtained through PUBS may be used for prenatal testing of fetal chromosomes.

Products of Conception (POC) - fetal biopsies, blood, or tissue samples. Cord or cardiac blood at delivery, even from fetal demises in utero, can be successful. Skin, lung, placenta, including membranes near the base of the unbilical cord. These samples will be processed for chromosome analysis and/or molecular cytogenetics (FISH).

Fluorescence in-situ Hybridization (FISH)  Analysis - is a technology involving hybridization, or binding, of specific DNA probes to the chromosomes of fetal cells obtained by amniocentesis, CVS, fetal blood, or products of conception.

FISH provides rapid diagnosis in high risk or late gestation pregnancies or when results are not available by chromosome analysis. FISH analysis can also identify microdeletions associated with certain genetic diseases in cases where there is a family history of disease or if a deletion is suspected by cytogenetics. Available tests include probes for:

•  DiGeorge/VeloCardioFacial syndrome (chromosome 22)

•  Interphase FISH Prenatal Aneuploidy Screen (AneuVysion) - consists of a panel of probes that identifies an extra or missing copy for chromosomes 13, 18, 21, X and Y only. The AneuVysion assay does not detect translocations, inversions, deletions, or other structural abnormalities involving these chromosomes.

• Prader Willi / Angelman Syndromes - Identifies deletions of paternal chromosome 15 (Prader-Willi) or maternal chromosome 15 (Angelman)

Minimum Specimen Requirements

Peripheral Blood

5.0 cc in Sodium heparin (green-top) vacutainer.
Transport at Room Temperature or Store at 2-8 C overnight (if necessary).

Amniotic Fluid

2 (15ml) tubes. Send at room temperature.

CVS and Products of Conception

Send available specimen in STERILE container with RPMI media, Hanks balanced salt solution, or sterile saline.