FDA approves Affymetrix's blood test for developmental disabilities

Affymetrix ($AFFX) gained the FDA's OK for a first-of-its-kind blood test that can identify possible genetic causes behind a child's developmental delay or intellectual disability.

Regulators announced the de novo approval for the California company's CytoScan Dx Assay, a diagnostic known as a "post-natal" test. It relies on a blood sample and analyzes a genome all at once in order to detect telltale chromosomal variations tied to Down syndrome, DiGeorge syndrome and other developmental disorders, the Associated Press noted.

Approval stems, in part, from a study that compared CytoScan to other tests such as karyotyping and FISH chromosomal tests in 960 blood specimens, in which CytoScan proved to be an improved option versus the competition.

Karyotyping looks for structural changes in chromosomes and counts their number in amniotic fluid, blood, bone marrow or placenta, according to the NIH. FISH (fluorescent in situ hybridization) testing typically uses samples from blood or amniotic fluid to map genetic material in a person's cells, and is also used for cancer or predicting other diseases with genetic origins, breastcancer.org explained.

The FDA also determined that CytoScan successfully analyzed a patient's entire genome and could identify chromosomal variations in parts of the genome connected to intellectual and developmental disabilities.

Diagnostics companies have focused more of their energies in recent years developing prenatal tests that accomplish the same thing. Within the last few years, Sequenom ($SQNM), Ariosa Diagnostics, Natera and Illumina's ($ILMN) Verinata Health have all launched prenatal tests designed to identify chromosomal abnormalities behind a number of conditions, such as Down syndrome.

Alberto Gutierrez, director of the FDA's Office of In Vitro Diagnostics and Radiological Health, said in a statement that CytoScan comes to market as a new tool to help spot why a child faces a developmental delay or intellectual disability, and can lead to "appropriate care and support" for the child. The goal is to screen for these issues sooner so children can get the treatment they need more quickly.

Dr. Annemarie Stroustrup, an assistant professor of pediatrics at Mount Sinai Hospital in New York, told the Associated Press that the diagnostic test would not be used on all newborns.

"When there's something about the child that strikes us as unusual or pointing to a potential genetic disease, that's when we would use this testing," she said.

The infant testing market could be quite large. As many as 3% of children in the United States have some form of intellectual disability, according to the National Institutes of Health and the American Academy of Pediatrics.

- read the FDA release
- here's the AP's take