Chromosome Analysis

Blood

Products of Conception

Cordocentesis

Chromosome analysis is performed on peripheral blood, cord blood, products of conception or skin biopsy specimens from individuals suspected of having a chromosome abnormality.

Who Should Be Offered Chromosome Analysis?

• Couples experiencing infertility or 2 or more unexplained pregnancy losses or perinatal deaths (about 6% have a chromosomal abnormality)
• Products of conception or skin biopsies of fetal tissues from unexplained fetal losses
• Newborns with serious anomalies or three or more minor congenital abnormalities
• Newborns with ambiguous genitalia, small penis, or hypospadius
• Infants and children with developmental delays or unexplained mental retardation, learning disabilities or behavioral problems
• Individuals with Down syndrome, Fragile X, autism, DiGeorge, Prader-Willi, Angelman, and Smith-Magenis
• Females with inguinal hernia, primary or secondary amenorrhea, and/or proportional short stature
• Females with premature ovarian failure
• Males with oligospermia or azoospermia, because 5-14% have a chromosomal abnormality, including balanced translocations. All males seeking assisted reproductive technologies
• Males with small testes or gynecomastia
• Blood relatives of individuals with a structural chromosomal abnormality

What Other Testing Should be Performed on Specimens?
Fluorescence in situ hybridization (FISH) is a molecular test in which DNA probes are hybridized to chromosomes to detect the presence or absence of specific DNA regions. GeneCare provides the full range of DNA probes which can aid in the detection and delineation of chromosomal abnormalities.

Many chromosome deletions are so small (micro) they cannot be detected by chromosome analysis alone. The following microdeletion syndromes can be detected by FISH analysis: Angelman, DiGeorge/Velo-Cardio-Facial (Shprintzen), Miller-Dieker/Lissencephaly, Prader-Willi, Smith-Magenis, Williams, X-linked Ichthyosis (Steroid Sulphatase Deficiency) /Kallmann. Please inquire about other microdeletion syndromes.

Small marker chromosomes and structural rearrangements can be identified by special chromosome banding, FISH (paint, centromere, and subtelomere) and probe analysis.

About 6% of children with unexplained mental retardation have a microdeletion near the end of a chromosome (subtelomere). A subtelomere deletion will not be seen by routine or high resolution chromosomal analysis. These deletions can be detected using special FISH probes. Subtelomere analysis should be considered for all children with unexplained mental retardation.

Other DNA testing such as PCR analysis, Southern analysis for direct DNA or linkage analysis and comparative genome hybridization is also available. Please contact our Centers for any DNA testing.

Specimen Collection and Transport

• Call GeneCare at (800) 277-4363 for consult and questions about testing or transport
• Complete test Request Form
• Label each specimen tube with patient name, birth date and collection date
• Transport by courier or priority overnight including specimens for Saturday Deliveries by Federal Express (800) 238-9070
• Please notify our Center of specimen collection and transport to insure successful delivery. Specimens are accepted 7 days a week.

Specimen Requirements

• BLOOD: Draw 1-10 ml peripheral vein, cord, or cardiac (less than 12 hours after fetal death) blood into a sodium heparin (200 units) vacutainer or plastic BD syringe. Blood drawn in syringe should be gently transferred to green top (Na Heparin) vacutainer for transport. Patients should avoid fatty foods and alcohol 12 hours before blood draw.
 
• SKIN, CORD, AMNION, OR CHORION: For fetal deaths, stillborns and neonatal deaths, obtain cord, skin and blood immediately. Call our Center for free tissue culture media or draw a 10 ml red top vacutainer from mother or other person, spin and remove serum with sterile syringe and needle and transfer to another sterile tube. Aseptically obtain cord, amnion, chorion and villi samples. Place in a serum tube. If the fetus is not macerated, obtain 10 mm sterile (alcohol wipe) skin dermis and tendon biopsy from above the knee using a sterile needle and scalpel. If the biopsy is not sterile, shake biopsy vigorously in saline in a closed sterile tube. Transfer biopsy to the maternal serum or Hank’s solution tube. Refrigerate until transported. Do not freeze.

Turnaround Time (Avg.)

Blood Chromosome	5 days
STAT Blood	48 hours
POC/Skin	8 days
DNA testing	7 days

Results Reporting 
GeneCare promptly reports results by telephone, fax, and/or mail. All abnormal results are promptly telephoned to the designated contact by one of our medical staff.

[About GeneCare] [Paternity Testing] [Physician Info] [Patient Info] [Conferences] [What's New?] [Awards]
[QuadInhibin][Employment Opportunities] [Contact Us] [Purchase Books] [Privacy Statement]
[Site Index] 
Last modified: May 25, 2004 04:26 PM

  © 2003 GeneCare, All Rights Reserved.