By Lam Vo
On Thursday, Oct. 16, the Olin Lecture Hall welcomed special guest speaker Dr. Michelle Caggana for a joint seminar of Union’s Chemistry and Biology Departments.
Caggana comes from the New York State Department of Health. Her talk was entitled “Newborn Screening, Biochemistry and DNA Technology to Improve Infant and Public Health.”
Caggana is currently the director of the Newborn Screening Program, deputy director of the Division of Genetics at Wadsworth Center and a faculty member at Wadsworth School of Laboratory Sciences.
She joined the Wadsworth Center in 1996 after receiving her doctoral degree from the Harvard School of Public Health and completing post-doctoral work in molecular virology at Wadsworth Center and clinical molecular genetics at Mt. Sinai School of Medicine.
Caggana began her talk by giving an overview of her program.
Newborn screening is a public health program designed to screen infants shortly after birth for a list of conditions that are treatable but not necessarily clinically evident in the newborn period.
In other words, it serves as a form of early protection against diseases that have not exhibited any symptoms in a newborn yet.
There are around 1,000 newborns being screened for these diseases in the state of New York everyday.
The testing procedure is simple: Most newborn screening tests are done by measuring metabolites and enzyme activity in whole blood samples collected from a baby’s heel onto specially designed filter paper.
The filter paper is often attached to a form containing required information about the infant being tested and his or her parents.
Infants who test positive for any of the diseases for which they are screened undergo further testing to determine if they are truly affected by a disease or if the test result was a false positive.
Follow-up testing is typically coordinated between geneticists and the infant’s physician.
To help the attendees of her talk have a better look at this process, Caggana discussed a condition for which the Wadsworth Center is currently screening: Krabbe disease.
Krabbe disease is caused by the complete deficiency of the enzyme galactocerebrosidase.
It is considered both a lysosomal-storage disorder and a leukodystrophy involving the central and peripheral nervous systems.
Krabbe disease generally presents in the first six months of life and leads to death before the age of two.
Stem-cell transplantation and chemotherapy prior to the onset of symptoms have been shown to stabilize the disease to a certain level.
The screening for Krabbe starts with a 3-millimeter “punch” taken from the baby and transferred to the Krabbe testing laboratory.
Mass spectrometry is used to test the sample for GALC activity. An infant with GALC activity greater than 12 percent of the daily mean is considered to be screen-negative.
DNA analysis is initiated for any sample with confirmed enzyme activity less than 12 percent of the daily mean.
In this step, the specimen is tested for polymorphisms and common mutations.
If no mutations and only polymorphisms are observed after sequence analysis, the infant is considered to be screen-negative.
If one or more mutations are found and confirmed, the infant is considered to be screen-positive and a physician is notified immediately.
If no mutations are found, sequence analysis is performed. If sequence analysis demonstrates any mutation, the infant is considered to be screen-positive and a physician is notified immediately.
After this stage, the Newborn Screening Program staff reports positive results to a child neurologist specialist at the treatment center nearest to the infant’s home for further evaluation and testing.
If the baby is found to have a high risk of Krabbe — no sign of GALC activity — he or she will be sent to a transplant center for treatment.
Caggana also mentioned two other diseases for which infants can be effectively tested and transferred for further treatment. One of them was X-ALD, X-linked adrenoleukodystrophy disease, which is a disorder of peroxisomal fatty acid beta oxidation.
X-ALD results in the accumulation of very long chains of fatty acids in tissues throughout the body.
This affects the central nervous system and causes poor memory, poor articulate skill, visual loss, deafness and seizures.
The other disease is Pompe disease, which is an inherited lysosomal disorder caused by the buildup of a complex sugar called glycogen in the body’s cells.
This accumulation of glycogen in certain organs and tissues impairs an infant’s ability to function normally.
Thus, Pompe can lead to muscle weakness, heart problems and breathing problems.
Krabbe, X-ALD and Pompe disease are the three most recent conditions added to the panel of 47 conditions being screened for in newborns by the state of New York.
Since the newborn period is an extremely important stage in every child’s development, we hope that Caggana’s program will continue to help parents take better, sometimes crucial, care of the children’s health.