X-Inactivation (X-I) Studies

Clinical info Determination of maternal and paternal X chromosome activation status is useful in the diagnostic analysis of nonrandom patterns. Skewed patterns of inactivation in female carriers of a number of X-linked recessive disorders and asymptomatic female carriers of some X-linked dominant diseases have been observed. By using the methylation-sensitive restriction enzyme HpaII and the polymerase chain reaction, the methylation status of both the maternal and paternal X chromosome is determined. Methylation of the HpaII restriction endonuclease site in the human androgen-receptor gene, HUMARA, correlates with X-inactivation. In approximately 10% of cases, the testing is uninformative due to the presence of the same allele size on both X chromosomes.
Indications X-inactivation studies are useful in diagnosing some X-linked recessive disorders and determining carrier status of family members
Specimen Requirements 5 to 10 ml of peripheral blood collected in an EDTA (lavender top) Vacutainer tube is preferred. The minimal blood needed for reliable DNA isolation is 3 ml
Transport The specimen should be kept at room temperature and delivered via overnight shipping. FedEx is preferred. If shipment is delayed by one or two days, the specimen should be refrigerated and shipped at room temperature. Do not freeze the specimen. Samples collected on Friday can be safely designated for Monday delivery.
Turnaround time 2 weeks
CPT Codes 81401
Cost $350
Contact For further information contact one of our This email address is being protected from spambots. You need JavaScript enabled to view it. at 1-800-473-9411.

Cytogenetics Lab

The Cytogenetics Lab provides high quality analysis for the detection of both constitutional chromosomal aberrations as well as abnormalities related to hematological malignancies

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