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Lab Manual for UCSF Clinical Laboratories

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Inherited Classic Cytogenetics Disorders

Contact & Specimen Information

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Prenatal Cytogenetics Analysis
Service Name

Amniotic fluid cytogenetics analysis

Request Service

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

Request Service

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

Request Service

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.

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Postnatal Cytogenetics Analysis
Service Name

High-resolution blood cytogenetics analysis

Request Service

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

Request Service

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

Request Service

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

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Molecular Cytogenetics Analysis
Service Name

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

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