The Food and Drug Administration authorized for marketing a postnatal diagnostic test that helps detect genetic causes of developmental delay or intellectual disabilities in children, but it is not intended to be used as a stand-alone test, the agency announced on Jan 17.
With a blood sample, the CytoScan Dx Assay analyzes the entire genome and detects chromosomal variations in regions of the genome that are associated with intellectual and developmental disabilities, such as DiGeorge syndrome, according to the FDA statement. The statement emphasized that is should not be used as a stand-alone diagnostic test, or for preimplantation or prenatal testing or screening; population screening; "or for the detection of, or screening for acquired or genetic aberrations occurring after birth, such as cancer."
Moreover, test results "should only be used in conjunction with other clinical and diagnostic findings, consistent with professional standards of practice, including confirmation by alternative methods, evaluation of parental samples, clinical genetic evaluation, and counseling as appropriate," the statement said. Results should only be interpreted by health care professionals who are board certified in clinical cytogenetics or molecular genetics.
Evaluation of the test included a comparison of results of almost 1,000 blood samples, which found the test was better at detecting certain chromosomal abnormalities than karyotyping and fluorescence in situ hybridization (FISH) chromosomal tests.
"This new tool may help in the identification of possible causes of a child’s developmental delay or intellectual disability, allowing health care providers and parents to intervene with appropriate care and support for the child," Alberto Gutierrez, Ph.D., director of the office of in vitro diagnostics and radiological health in the FDA’s Center for Devices and Radiological Health, said in the statement.
The test is manufactured by Affymetrix.