Sanford Watertown

Over the years, advances in genetic testing have improved doctors’ ability to treat and diagnose certain illnesses. By analyzing small samples of blood or body tissue, doctors can use genetic tests to determine whether someone carries gene mutations or chromosome rearrangements for certain inherited disorders. Now, the Sanford Clinic USD Genetics Laboratory offers an advancement in that technology: microarray testing.

The Cytogenetics Whole Genome Array* allows screening of a patient’s entire genome at a finer resolution than can be achieved by light microscopy. The test is highly effective at detecting something (a section of DNA) that is missing from a chromosome or something extra (an additional copy of a section of DNA) that shouldn’t be there. While this test can’t see everything, it does allow for detection and diagnosis that the microscope alone doesn’t allow.

The lab’s director, Patricia Crotwell, PhD, says this type of genetic test had to be sent out of state in the past but now can be performed here in South Dakota. She adds, “Furthermore, this technology allows us to see gains and losses of genetic material that we simply can’t see at the microscope. Now, a single test can look for all of the common micro-deletion and micro-duplication syndromes at one time, which can lead to faster answers for healthcare providers and families of affected patients than if we tested for one syndrome at a time. It won’t replace a good clinical genetics evaluation, of course, but we expect it to be very helpful in determining whether a patient’s symptoms or physical findings are related to chromosome imbalances, even if those are too small to have been detectable in the past.”

Patients with the following characteristics are most likely to benefit from microarray testing:
• Congenital anomalies or birth defects
• Delayed growth and psychomotor development
• Autism spectrum disorders
• Abnormal sexual development
• Abnormal or unusual physical features
• Seizures or neurological dysfunction
• Chromosome abnormalities

Although this new technology allows for diagnosis of a broad range of genetic disorders, it does not replace the need for a clinical genetics evaluation or genetic counseling.

*This microarray chip was constructed by Affymetrix for the sole purpose of identifying DNA copy number gains and losses associated with chromosomal imbalances. This test was developed and its performance characteristics determined by the Sanford Clinic USD Genetics Lab as required by CLIA ’88 regulations. It has not been cleared or approved for specific uses by the U.S. Food and Drug Administration. Pursuant to the requirements of CLIA ’88, this laboratory has established and verified the test’s accuracy and precision.