FDA OKs Postnatal Blood Test for Intellectual Disabilities

Megan Brooks


January 17, 2014

The US Food and Drug Administration (FDA) has cleared for marketing the CytoScan Dx Assay (Affymetrix), which detects chromosomal variations that may underlie a child's developmental delay or intellectual disability.

It is estimated that 2% to 3% of children in the United States have some form of intellectual disability. Many intellectual and developmental disabilities, such as Down syndrome and DiGeorge syndrome, are associated with chromosomal variations.

The CytoScan Dx Assay "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, PhD, director of the Office of In Vitro Diagnostics and Radiological Health in the FDA's Center for Devices and Radiological Health, said in a statement released today.

The agency's review included an analytical evaluation of the test's ability to accurately detect numerous chromosomal variations of different types, sizes, and genome locations when compared with several analytically validated test methods.

The FDA found that the CytoScan Dx Assay can analyze a patient's entire genome and adequately detect chromosome variations in regions associated with intellectual and developmental disabilities.

The FDA also reviewed results of a study that compared the performance of the CytoScan Dx Assay with other tests commonly used for detecting chromosomal variations associated with a developmental delay or intellectual disability.

"A comparison of test results from 960 blood specimens showed the CytoScan Dx had improved ability over commonly used tests, including karyotyping and [fluorescent in situ hybridization] chromosomal tests, to detect certain chromosomal abnormalities," the agency said.

The FDA cautions that the test should not be used for stand-alone diagnostic purposes, preimplantation or prenatal testing or screening, population screening, or the detection of or screening for acquired or genetic aberrations occurring after birth, such as cancer.

They further advise that the test 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.

"Interpretation of test results is intended to be performed only by health care professionals who are board certified in clinical cytogenetics or molecular genetics," the agency said.

The FDA reviewed the assay through its de novo classification process, a regulatory pathway for some novel low- to moderate-risk medical devices.


Comments on Medscape are moderated and should be professional in tone and on topic. You must declare any conflicts of interest related to your comments and responses. Please see our Commenting Guide for further information. We reserve the right to remove posts at our sole discretion.
Post as: