New Genetic Tests, Next-Generation Technology Improve Diagnosis of Congenital Disorders
by The Robert W. Woodruff Health Sciences Center of Emory University - 05/20/10
New panels of genetic tests, linked with next-generation gene-sequencing equipment and software, should significantly enhance diagnosis of newborns, children and adults with three groups of rare but extremely serious developmental disabilities and degenerative neurological disorders.
The panels were developed by Emory Genetics Laboratory within the Department of Human Genetics at Emory University School of Medicine.
"The evaluation of a newborn, a child or an adult with developmental disabilities or with a degenerative neurological disorder is a challenge even for the best diagnostician," says Paul Fernhoff, MD, Emory associate professor of human genetics. "The evaluation usually involves testing of multiple blood and urine samples and the need to send these samples to several different laboratories.
"These new panels, developed by scientists at Emory Genetics Laboratory, test for groups of rare disorders that can now be confirmed efficiently with minimal clinical time and effort. These panels greatly enhance our ability to diagnose rare disorders and to avoid the time and expense of the usual diagnostic odyssey for our families."
The three test panels and related diseases now available for ordering are:
Congenital Disorders of Glycosylation Panel (CDG Panel)
This group of more than 30 genetic disorders is caused by an alteration in synthesis and structure of protein and lipid glycosylation, an enzyme process that is essential for the function of nearly all organ systems. Clinical disorders range from severe developmental delay and hypotonia (loss of muscle tone), with multiple organ systems involved beginning in infancy, to hypoglycemia and protein-losing enteropathy (intestinal disorder) with normal development.
The new Next Generation CDG sequencing panel includes simultaneous analysis of 24 genes known to cause CDG. Complemented by its comprehensive biochemical testing panel, EGL's CDG test offering allows for efficient and informative diagnosis.
Congenital Muscular Dystrophy Panel (CMD Panel)
The congenital muscular dystrophies are a group of genetically and clinically heterogeneous hereditary myopathies characterized by congenital hypotonia and muscle weakness, contractures (shortened muscles and joints), and delayed motor development.
The new Next Generation CMD sequencing panel includes simultaneous analysis of 12 genes known to cause CMD, enabling an accurate clinical diagnosis without the need for invasive muscle and skin biopsies.
X-Linked Intellectual Disability Panel (XLID Panel)
It is estimated that up to 25-30 percent of X-Linked Intellectual Disability syndrome cases can be attributed to a genetic cause, of which fragile X syndrome is the most common. Fragile X affects about one in 5,000 males with moderate to severe intellectual disability and carrier females with milder clinical symptoms. Current diagnostic testing involves analysis of only a few XLID genes and is both time-consuming and expensive.
A new Next Generation XLID sequencing panel includes simultaneous analysis of 90+ genes that have clear associations with X-Linked Intellectual Disability.
The three new test panels are made possible by next-generation technologies that provide significant improvements in efficiency, speed and quality.
- Emory Genetics Laboratory recently acquired a new Applied Biosystems SOLiDTM System that enables analysis of multiple genes concurrently, making it significantly easier to analyze disorders in which there are many possible candidate genes. All three new test panels will be run on the ABI SOLiD System.
- A new Raindance Technologies instrument can select and amplify large genetic regions. This technology is useful in panels targeting a large number of genes where there is low volume for each particular test. The Raindance technology enriches genetic coding regions and surrounding sequences, thus providing significant improvements over current technology - single amplicon PCR - which is time consuming, inefficient and prone to errors when processing large numbers of amplicons.
- Emory Genetics Laboratory has partnered with Softgenetics to enhance NextGENe, SoftGenetics' next-generation sequencing analysis software. The NextGENe software can pick up the full spectrum of possible mutations for any Next Generation sequencing panels. This is the first and only software available to pick up large and small deletion and duplication mutations, in addition to single nucleotide changes on the SOLiD platform.
Development of the CMD panel was funded by the Muscular Dystrophy Association and the National Institute of Neurological Disorders and Strokes (NINDS) of the National Institutes of Health (NIH). The CDG and XLID panel development was funded by the Collaboration Education and Test Translation (CETT) program as part of the Office of Rare Diseases of the NIH. CETT facilitates the translation of genetic tests from the research setting to Clinical Laboratory Improvement Amendments (CLIA)-certified laboratories through collaborations among clinicians, laboratories, researchers and disease-specific advocacy groups. The acquisition of the Raindance instrument was made possible through a grant from the Clinical & Translational Science Institute.
Emory Genetics Laboratory, within the Department of Human Genetics at Emory University School of Medicine, is a comprehensive clinical genetics testing laboratory (cytogenetics, molecular and biochemical services) specializing in molecular cytogenetics, rare disease testing and newborn screen confirmatory testing. For more information, visit http://geneticslab.emory.edu.
The Robert W. Woodruff Health Sciences Center of Emory University is an academic health science and service center focused on missions of teaching, research, health care and public service. Its components include the Emory University School of Medicine, Nell Hodgson Woodruff School of Nursing, and Rollins School of Public Health; Yerkes National Primate Research Center; Winship Cancer Institute of Emory University; and Emory Healthcare, the largest, most comprehensive health system in Georgia. Emory Healthcare includes: The Emory Clinic, Emory-Children's Center, Emory University Hospital, Emory University Hospital Midtown, Wesley Woods Center, and Emory University Orthopaedics & Spine Hospital. The Woodruff Health Sciences Center has a $2.5 billion budget, 17,600 employees, 2,500 full-time and 1,500 affiliated faculty, 4,700 students and trainees, and a $5.7 billion economic impact on metro Atlanta.