by Ken Alltucker – Oct. 5, 2012 12:00 AM
The Republic | azcentral.com
The TGen Center for Rare Childhood Disorders will use the institute’s gene-hunting technology to identify causes of ailments that can confound doctors.
The idea is that scientists working with doctors, can uncover the genetic triggers to rare disorders. Once the cause is identified, doctors can evaluate potential drugs or treatments.
“When you are dealing with a rare disorder, even with a child, it has a high likelihood of being genetic,” said Matthew Huentelman, who will be co-director of the new center. “There are thousands of disorders with names and probably thousands of others without names that are just a collection of symptoms. We know it is a big problem and it affects a lot of lives across the Valley.”
Huentelman said such rare diseases or disorders afflict as many as 1 in 150 children. These children at times are subjected to a dozens of medical tests, biopsies and scans. that can frustrate them and their families, particularly when the cause of the disease or disorder remains a mystery.
TGen identified rare childhood diseases as a potential area of study when the Phoenix-based research institute was established a decade ago. As technology has improved and whole-genome sequencing has grown more affordable, TGen decided to use the sequencing technology to study children with these disorders.
TGen started the effort more than a year ago and evaluated the genetic makeup of five children. In three cases, scientists were able to find the genetic causes of their disorders.
The first case studied by TGen involved 12-year-old Shelby Valint of north Phoenix. Shelby had difficulty talking, walking and eating, but doctors could not pinpoint the cause of her illness after years of testing. She needed a motorized wheelchair or a walker to get around. After her genome was sequenced, TGen scientists and her pediatric neurologist, Dr. Vinodh Narayanan, discovered a genetic anomaly that blocked her ability to synthesize dopamine, a brain chemical tied to movement, muscle control and balance. Narayanan prescribed a drug, bromocriptine, that is often used to treat Parkinson’s disease.
Within three months of taking the drug in December 2010, Shelby began to walk and talk and live an otherwise normal life. Narayanan is still closely monitoring her progress, and TGen plans more extensive genetic scans as scientists seek answers to what appears to be a type of neurotransmitter metabolism disorder, he said.
TGen’s new program also has helped diagnose two families with mitochondrial disease. One child has passed away.
TGen has since expanded its genetic testing to more than 20 children, and the research institute has collected about 100 DNA samples of children with rare disorders, said David Craig, co-director of the new TGen center. Craig said he is hopeful that TGen can find genetic triggers for about half of the cases researchers study. There will not be known drug treatments for some diseases, but families may find relief even in knowing the diagnosis, Narayanan said.
TGen President Jeffrey Trent said the new center is another example of how genetic sequencing can be used to diagnose and help treat patients. The Phoenix research institute routinely sequences genomes for cancer patients at Mayo Clinic, Scottsdale Healthcare and other hospitals. Trent said the new center will be funded by TGen, foundations, philanthropy and, potentially, payments from health insurance companies. He estimates 20 to 30 percent of sequencing cases could be reimbursable by private insurers.
“TGen was formed a decade ago to use genomic information for medical benefit,” Trent said. “I feel like that hope has been realized. Genetic medicine is ready today.”