Early Treatment for Metabolic Disorders Prevents Disability, Saves Lives

Tuesday, June 26, 2001

ROCHESTER, MINN. — Babies now born at Mayo Clinic hospitals in Rochester can be screened for more than 20 metabolic disorders. Combined, these disorders affect about one in 4,000 newborns.

Metabolism — the process of turning food into energy — involves thousands of steps. A defective gene can make the process go awry, sometimes soon after birth. The disorders can cause severe illness and consequences including mental retardation and death. Though a defective gene in the baby causes the disorders, parents likely would not know they carried such a gene.

"If we know the child has the disorder before symptoms appear, in many cases, we can provide effective treatment," says Gerard Vockley, M.D., Ph.D., professor and chair of the Mayo Clinic's Department of Medical Genetics and a specialist in biochemical genetics. "With proper treatment — often just adjustments in diet — many children with these metabolic disorders will have a chance to grow and develop normally."

The cost of the test, about $50, is included in delivery charges.

"Based on the number of births at Mayo hospitals each year, we would expect to identify one or two newborns a year with one of these disorders," says Dietrich Matern, M.D., a pediatrician, geneticist and co-director of Mayo Clinic's Biochemical Genetics Laboratory.

How the screening is done A nurse draws a small blood sample from the infant's heel. The blood is dried on absorbent paper and analyzed by tandem mass spectrometry at Mayo Clinic's Biochemical Genetics Laboratory, one of the largest laboratories of its kind in the nation. The laboratory will use reference values and procedures developed by Neo Gen Screening Inc., an independent laboratory with expertise in high-throughput newborn screening using tandem mass spectrometry. Within three minutes, this device creates a metabolic profile of the baby's blood. It is compared to normal ranges based on the database of more than one million newborns obtained from Neo Gen Screening.

"By using this large database, we can provide the most accurate screening currently possible," says Dr. Matern. "Our hope is to identify all of the babies with the disorders and minimize the number of 'false positives,' which cause needless anxiety for the families."

Test results will be available to families in 24 to 48 hours. If results indicate a metabolic disorder, the family would be referred to a specialist in metabolic disorders for an immediate confirmation and evaluation.

States require some newborn screenings The expanded newborn testing supplements state-mandated screening, which varies from state to state. Typically, states require screening for a small number of genetic disorders. Minnesota and other states are taking steps to make expanded genetic testing available to all newborns.

"Grassroots parents organizations have been great advocates for more comprehensive newborn evaluations," says Piero Rinaldo, M.D., Ph.D., a geneticist, pediatrician and also co-director of Mayo Clinic's Biochemical Genetics Laboratory. "In large part because of their efforts, these expanded tests are becoming the standard in newborn care."

Contact: Chris Gade 507-284-2430 (days) 507-284-2511 (evenings) e-mail: newsbureau@mayo.edu

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