On The Spot e-News
Volume 4, Issue 2 | February 2009
In this issue:
- Signature Receives New York Clinical Laboratory Permit
- SignatureChip Coverage of Schizophrenia Loci
- Characterization of 22q11.21-q11.23 Duplications Distal to DGS/VCFS Critial Region
- 2009 Scientific Microarray Conference
Signature Genomic Laboratories Receives New York State Clinical Laboratory Permit
Signature has received its New York Clinical Laboratory Permit. The permit allows Signature to receive specimens drawn by clinical laboratories in the state of New York, in accordance with the New York State Department of Health, Wadsworth Center’s Clinical Laboratory Evaluation Program. Signature is the first laboratory to receive a New York permit to perform array CGH.
New York healthcare must include a signed Consent for Molecular Cytogenetic Testing when submitting samples to Signature for testing.
SignatureChip Covers Regions of the Genome Associated with Schizophrenia
The SignatureChip® covers regions of the human genome that were known and recently published to be associated with susceptibility to schizophrenia.
A study led by investigators from Duke University and published Feb. 6 in PLoS Genetics examined 1073 individuals with schizophrenia and 1148 unaffected control individuals. Among individuals with schizophrenia, investigators identified eight deletions larger than 2 megabases (Mb), none of which were present in the control group or in an additional control group of 1378 individuals. The deletions encompassed loci on chromosomes 1 and 22 that have been previously implicated in schizophrenia and regions on chromosomes 8 and 16 that have not been previously associated with the disease.
In addition to backbone coverage of the genome, the SignatureChip covers more than 1,500 genes involved in developmental disabilities and known syndromes, including coverage over each of the eight loci identified in the Duke study. Signature has tested over 30,000 patients by array CGH and developed a repository of all abnormalities identified in this population. A review of this data shows alterations in these regions in individuals with schizophrenia.
"It is very gratifying when independent studies corroborate the value of the design of our arrays and affirm their clinical utility in the study of neurodevelopmental disorders," said Bassem A. Bejjani, M.D., Chief Medical Officer at Signature. "We have designed these arrays with specific coverage of areas of the genome that are likely to be associated with such disorders in addition to other developmental disorders such as autism. As a result, we regularly identify newly recognized disease loci and help families in their quest for a diagnosis."
Characterization of 22q11.21-q11.23 Duplications Distal to DGS/VCFS Critial Region
A group led by researchers at Signature recently characterized 18 individuals with submicroscopic gains of DNA on chromosome 22 and suggest that duplication alone may not account for the clinical features in those individuals.
In the study, published in Human Molecular Genetics, researchers identified 18 individuals with duplications of 22q11.21-q11.23 distal to the DiGeorge/velocardiofacial syndrome region among more than 20,000 individuals with unexplained mental retardation and congenital anomalies referred to the laboratory for microarray testing. The clinical features of the individuals varied widely, with contradicting clinical features?macrocephaly versus microcephaly, for example,present in some. In addition, there appeared to be no correlation between the severity of the individuals’ clinical features and the size or location of their duplications. Of 11 cases for whom parental DNA samples were available for testing, one had a duplication not present in either parent and 10 inherited the microduplication from a parent, two of whom reportedly have learning problems or developmental delay. Because some of the duplications were inherited from a clinically normal parent, the clinical significance of these duplications is unclear and may require an as-yet unidentified genetic modifier for medical problems to occur.
"Although further studies are required to determine what role these duplications play in the patients’ clinical features, microarray analysis was essential for identifying this novel chromosome abnormality. Their highly variable clinical features—and the lack of similar patients reported in the literature—would have prevented their identification without this technology," said Justine Coppinger, Certified Genetic Counselor at Signature and lead author of the study. "These cases are an excellent example of how microarray technology can provide answers that traditional methods of genetic testing cannot."
Signature Announces 2009 Microarray Conference
Signature welcomes its clients to the 2009 Scientific Microarray Conference June 19-20 at the Doubletree Hotel in Spokane. The only event of its kind in the United States, the Scientific Microarray Conference brings together medical professionals who use Signature’s microarray diagnostic technology in their practices for a weekend of discussion about the clinical applications of this technology. To foster an intimate environment for the free sharing of information, conference attendance has been capped at 100 registrants. More information is available on our conference page.
Meeting attendees are encouraged to submit abstracts for platform presentation at the 2009 Signature Scientific Microarray Conference. Selections will be made and presentation times determined by the Conference Committee. Abstracts should be submitted via e-mail by April 1, 2009, 5 PM PST. Abstract submission instructions are available here.