Amniotic fluid cytogenetics analysis

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Indications for analysis:

• Advanced maternal age (over 35 at time of expected delivery)
• Abnormal maternal serum screen
• Abnormal ultrasound findings
• Previous pregnancy with a chromosome abnormality
• Family history of chromosome abnormalities
• Others (twin pregnancies, IVF and other conditions, patient anxiety, etc.)

Specimen and volume:

• 20-30 ml of clear, fresh, sterile amniotic fluid in two sterile 15 ml centrifuge tubes with screw cap.
• Specimens need to be transported immediately to the laboratory at room temperature.
• Complete a Cytogenetics Request Form. Indicate test requested including FISH, and include gestational age at time of specimen collection.

Analysis:

• G-banding: a minimum of 15 metaphases from 15 colonies with a minimum of 2 in situ cultures.
• Fluorescence in situ hybridization (FISH) for trisomy 13, 18 and 21 and for sex chromosome aneuploidy: 100-200 uncultured interphase nuclei.
• FISH for microdeletions: 10 metaphase cells
• Amniotic fluid alpha-fetoprotein assay and acetylcholinesterase assay (when indicated): sent to a UC reference lab for testing.

Chorionic villus sampling (CVS) chromosome analysis

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Indications for analysis:

• Advanced maternal age (over 35 at time of expected delivery)
• Previous pregnancy with a chromosome abnormality
• Abnormal ultrasound findings
• Family history of chromosome abnormalities
• Others (IVF, multiple miscarriages, patient anxiety, etc.)

Specimen and volume:

• Submit 20-30 mg chorionic villus in sterile, plastic, screw-top tubes filled with sterile transport media.
• Specimens need to be transported immediately to the laboratory at room temperature.
• Complete a Cytogenetics Request Form. Indicate test requested including FISH, and include gestational age at time of specimen collection.

Analysis:

• G-banding: a minimum of 20 metaphases from a minimum of 2 cultures.
• Fluorescence in situ hybridization (FISH) for trisomy 13, 18 and 21 and for sex chromosome aneuploidy: 100-200 uncultured interphase nuclei.
• FISH for microdeletions: 10 metaphase cells.

Fetal tissue cytogenetics analysis

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Indications for analysis:

• Recurrent SAB
• Fetal anomalies

Specimen and volume:

1. Submit 30mg sample from the fetal side of the placenta at the site of cord insertion, and if possible 30mg sample from one or two of the following tissues: gonad, kidney, cartilage, umbilical cord, or membranes. Obtain samples using aseptic technique.
2. Specimens need to be transported immediately to the laboratory at room temperature.
3. Complete a Cytogenetics Request Form. Indicate test request and include gestational age at time of specimen collection.

Analysis:

• G-banding: a minimum of 20 metaphases from a minimum of 2 cultures.
• Fluorescence in situ hybridization (FISH) for trisomy 13, 18 and 21 and for sex chromosome aneuploidy (if cell cultures were unsuccessful): 100-200 uncultured interphase nuclei.

High-resolution blood cytogenetics analysis

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Indications for analysis:

• Developmental delay
• Growth retardation
• Multiple congenital anomalies
• Mental retardation
• Ambiguous genitalia
• Possible balanced translocation carrier
• Recurrent miscarriages
  1. Positive family history for abnormal pregnancy outcom
  2. Phenotype suggestive of a particular microdeletion or microduplication syndrome
  3. Other phenotypic anomalies

Specimen and volume:

• Submit 3-5 ml peripheral blood specimen in sodium heparin green top tubes.
• Specimens need to be transported immediately to the laboratory at room temperature.
• Complete a Cytogenetics Request Form, and include indication for analysis and all tests requested including FISH.

Analysis:

• G-banding analysis (at >550 band stage): a minimum of 20 metaphases.
• FISH for microdeletion syndromes: a minimum of 10 metaphase cells for each probe.
• FISH for the subtelomere regions: a minimum of 5 metaphase cells for each probe mix.
• Other specific banding analysis (C-, Q-, NOR-banding): please contact the laboratory.

Skin Biopsy Cytogenetic Analysis

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Indications for analysis:

• Tissue limited mosaicism
• Culture for other studies, such as biochemical and molecular studies

Specimen and volume:

• Submit a 3-4 mm² skin biopsy sample in a sterile, plastic, screw-top tube filled with sterile tissue culture medium or sterile saline solution.
• Specimens need to be transported immediately to the laboratory at room temperature.
• Complete a Cytogenetics Request Form with instruction for send-out studies.
• If it is necessary to hold a tissue sample overnight, please refrigerate. Do not freeze.
• Specimens need to be transported immediately to the laboratory at room temperature.
• Complete a Cytogenetics Request Form. Indicate test requested including FISH, and include gestational age at time of specimen collection.

Analysis:

• G-banding analysis: a minimum of 20 metaphases.
• FISH on metaphase cells: a minimum of 10 metaphase cells for each probe.
• FISH on interphase nuclei: 100-200 nuclei.
• Culture for other studies: two T-25 flasks of cultured cells

Stem cell and cell line cytogenetics analysis

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Indications for analysis:

• Research

Specimen and volume:

• Submit two T-25 flasks of cultured cells that are ready for chromosome analysis with 3 day's of culture medium.
• Specimens need to be transported immediately to the laboratory at room temperature.
• Complete a Cytogenetics Request Form with instruction for keeping the cells growing in the lab for a short period.

Analysis:

• G-banding analysis: a minimum of 20 metaphases.
• Other studies upon request

Please contact the laboratory at 415-353-4844 for information regarding FISH analysis and chromosome microdissection-based analysis.