FISH Study: Microdeletion Metaphase – Steroid Sulfatase Deficiency (Xp22.3)
Peripheral Blood: Peripheral blood must be collected aseptically in sodium heparin tubes (usually green-top tubes) and immediately rotated thoroughly to prevent clotting. For infants, obtain approximately 2 cc. Obtain 5 - 7 cc for children and adults.
Note: A separate blood sample is required if a concurrent CGH microarray study is desired. Do not freeze or fix samples in any manner contrary to the maintenance of cell viability. Maintain sample sterility; keep all specimens at room temperature; and deliver samples to the laboratory within 24 - 48 hours. Ship specimens at room temperature for overnight delivery.
- Unacceptable Conditions:
- Frozen specimens
- Specimens > 48 hours old*
- Stability (collection to initiation of testing):
- Ambient: 24 - 48 hours*
- Frozen: Unacceptable
* Cell viability of specimens requiring cell culture may be compromised in specimens more than 48 hours old upon receipt. Refrigeration at 2° - 8° C may assist when a delay is not preventable. Do not freeze or place specimens directly on ice.
This test is used to detect microdeletions in the distal short-arm region of the X chromosome, which includes the STS gene locus, and have been reported in some patients with the X-linked ichthyosis.
Metaphase/Chromosome fluorescence in-situ hybridization (FISH) analyses; requires cell culture and a concurrent or previous routine karyotyping
10 - 28 days
By report; interpretive
Monday - Saturday