VMD4Kids test, now used by 30-40 pediatric hospitals nationwide for difficult-to-diagnose cases, targets 218 gene variants in mosaic disorders.
Doctors at Children’s Hospital Los Angeles (CHLA) have developed and validated a specialized genetic test that identifies mutations causing vascular anomalies and mosaic disorders in pediatric patients, providing a pathway to targeted treatments for these difficult-to-diagnose conditions.
The VMD4Kids (Vascular and Mosaic Diseases for Kids) test has become the primary diagnostic tool for clinics across the US dealing with complex vascular, lymphatic, and overgrowth disorders, according to researchers at the hospital’s Center for Personalized Medicine.
“About 30-40 mostly pediatric hospitals around the country send patient samples to us for the VMD4Kids test, as few do this type of testing themselves, and those that do have been sending their unsolved cases here to us,” says Matthew Deardorff, MD, PhD, director of translational genomics for the Center for Personalized Medicine at CHLA, in a release.
Addressing Market Gap in Specialized Testing
The test addresses a gap in the diagnostic market for pediatric genetic disorders. Only around five hospitals in the country perform comparable testing, with most using smaller, less extensive panels than the VMD4Kids system, according to Deardorff.
The current version of the VMD4Kids panel targets 218 gene variants and can detect mutations present at levels as low as 1% of affected tissue. The test is designed to be updated as new gene relationships are discovered, allowing laboratories to add new targets without rebuilding the entire panel.
Vascular anomalies result from genetic mutations that cause abnormal growth and development of blood or lymphatic vessels. Many of these mutations affect only certain cells in the body—a condition known as mosaicism—making them particularly challenging to detect through standard blood-based genetic testing.
“Because the genetic alterations that cause these conditions are not always present in all the cells of the body, a blood sample will not give enough information,” says Avinash Dharmadhikari, PhD, DABMGG, NYCQ, assistant director of the Clinical Genomics Laboratory, in a release. “This makes it important to test the affected tissue. But we only need a small skin biopsy or surgical specimen to do so, and this test also works on fixed/preserved (FFPE) tissue samples stored from previous surgery.”
Clinical and Commercial Implications
The test’s clinical utility extends beyond diagnosis to treatment selection. Several targeted therapies already exist for vascular anomalies caused by specific genetic mutations, including apelisib, which blocks PIK3CA gene activity, MEK inhibitors that reduce RAS pathway signaling, and MTOR inhibitors targeting another group of genes.
“When a child has a disorder that causes malformation and overgrowth of tissue, we try to find a genetic diagnosis as quickly as possible,” says Deardorff, in a release. “Because once we find the gene or genes involved, we can work to apply personalized treatments.”
The development team notes that the test’s design allows for easy updates as new genetic associations are discovered, providing laboratories with a scalable platform for expanding their genetic testing capabilities in the vascular anomaly space.
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