Institute of Genomic Medicine
Products of Conception Tissues from Aborted/Miscarried Fetuses
BACKGROUND
Fibroblast cultures are prepared from tissues obtained on products of conception or stillborn fetuses.
INDICATIONS FOR TESTING
- To determine reason for fetal demise
- To confirm a chromosomal abnormality in an aborted fetus
SAMPLE REQUIREMENTS
- Fetal Tissue (Fetus 14 or more weeks of gestation):
Send these tissues if possible:
- Cord blood-minimum 1 ml in a heparinized green top tube
- Skin and muscle 1 cm3 from lateral thigh
- Placenta 2 cm3 specimen including amnion at its surface obtained midway between the cord insertion and placental margin.
In case of excessive maceration, provide tissue from muscle, kidney, heart or lung.
- Products of conception:
Send the entire gestational sack if possible. If not available, select tissue containing villi. Fetal parts are difficult to identify early in gestation, and most other tissues, including blood clots, membranes and decidua result in growth of maternal cells
SPECIMEN HANDLING
- Fetal Tissue:
Place specimen in culture media with antibiotics (3X media). This media is available from the laboratory upon request. If media is not available, place on top of a sterile gauze pad moistened with water and place in a sterile container with lid. DO NOT SUBMERGE THE TISSUE IN SALINE OR WATER! DO NOT SEND THE ENTIRE FETUS!
- Products of Conception:
Place specimen in culture media provided by the laboratory, or send the specimen alone in a sterile container. Do not add saline or water.
- Fetal Tissue and POC culture failures: Microarray CGH results can be obtained from specimens that fail to grow in culture which is required for cytogenetic analysis.
Send these tissues if possible:
- Cord blood-minimum 1 ml in a heparinized green top tube
- Skin and muscle 1 cm3 from lateral thigh
- Placenta 2 cm3 specimen including amnion at its surface obtained midway between the cord insertion and placental margin.
In case of excessive maceration, provide tissue from muscle, kidney, heart or lung.
Send the entire gestational sack if possible. If not available, select tissue containing villi. Fetal parts are difficult to identify early in gestation, and most other tissues, including blood clots, membranes and decidua result in growth of maternal cells
Send either type of specimen to the laboratory the same day, by overnight mail, or refrigerate overnight and send the following day. Samples held up more than three days will not grow.
PROCEDURE
The tissues are cleaned and dissected in the laboratory. Villi are identified and separated from the remaining tissues. The cleaned tissues are then dissociated with collagenase (fetuses), or collagenase and trypsin (villi). Single cell suspensions are grown in cultures, which are ready to be harvested between 4 and 21 days. The time depends on the condition of the specimen at the time of arrival.
Twenty metaphase cells are analyzed and 2 karyotypes are prepared from each routine specimen.
INTERPRETATION
The analysis will detect fetal sex, and any gross abnormalities of the sex chromosomes or autosomes such as trisomies, monosomies, translocations, deletions and duplications. Deletions and rearrangements on the molecular level cannot be seen.
RESULTS
Results are presented according to the international standards for chromosomal nomenclature (ISCN), and a full explanation of the karyotype is provided. Any abnormal or variant results should be followed by genetic counseling.
Molecular and biochemical testing can also be done on fresh or cultured cells. If the cultures fail to grow and fetal tissue is available then Microarray based Comparative Genomic Hybridization (CGH) studies can be performed by the Molecular laboratory at your request.
