DNA sequencing of infants and children with anatomical defects of unknown causes

ScienceDaily (Nov. 6, 2012) A presentation at the American Society of Human Genetics 2012 meeting updated genetics experts about a one-year-old research initiative that brought together researchers, clinicians and policy experts to tackle the challenges of incorporating new genomic technologies into clinical care of newborns, infants and children with anatomical defects whose causes are unknown.

Among the challenges is interpreting how variations in patients' DNA cause or contribute to their medical problems, said Duke University Assistant Professor of Pediatrics Erica E. Davis, Ph.D., who presented the update and is based in the Center for Human Disease Modeling in the university's medical center.

In 2011, the center founded the Duke Task Force for Neonatal Genomics to act as a nucleus for a group of physicians and scientists with the diverse skills sets needed to bridge genetics, genomics, cell biology, ethics and clinical investigation and to offer a "360 degree" view of challenging clinical pediatric cases, Dr. Davis said.

"Strikingly, preliminary analysis of the task force's first year of work has suggested definitive or strong candidate diagnoses in some 90% of the recruited cases," she noted.

During its first year, the task force screened over 150 newborns, infants and children, enrolled 20 patients and developed the capacity to enroll about 100 patients each year.

"Our patients come from the Duke fetal diagnostic center, the Duke intensive care nursery and various pediatric specialty clinics," she said.

In one child with severe epilepsy, the task force used sequencing of the protein-coding regions of the genome (about 2% of the entire human genome) to identify a broken gene that impairs the ability of sodium to move in and out of cells.

"We determined that the child's condition was caused by a new mutation in a gene named SCN2A," Dr. Davis said.

This approach was also used to help diagnose genetic disorders in babies with a variety of conditions including congenital muscle weakness, fluid in the brain and kidney cysts.

"The task force's goal is to create a model of how and when genetic sequencing should be a first-tier diagnostic tool to inform and guide clinical management and treatment of young children with unexplained congenital defects," she said.

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DNA sequencing of infants and children with anatomical defects of unknown causes