The University of Washington Clinical Genomics Lab (CGL) is changing the method offered for targeted testing for small genomic copy number variants (CNVs – deletions and duplications). The droplet digital PCR test has been discontinued, and the CGL will instead use constitutional microarray analysis (CMA). Like with ddPCR, CMA, Familial Variant can be used to (1) test a person for a CNV found previously in a family member or (2) clarify the size and gene content of a CNV found previously in a person by a different test method, such as FISH, MLPA, or a gene panel. A copy of the prior test results must be provided if the original test wasn’t done by CGL.
The CMA-Familial Variant test uses the same microarray platform as the genome-wide CMA that the CGL offers, so the difference is in analysis and reporting. When CMA, Familial Variant is ordered, only the region of the specified copy number variant is analyzed and reported on. No other regions of the genome are evaluated.
Like with ddPCR, specialists in the UW Department of Lab Medicine and Pathology are happy to handle pre-authorization for CMA, Familial Variant on behalf of ordering providers. Also like ddPCR, the list price for CMA, Familial Variant is lower than genome-wide CMA.
Contact the CGL Laboratory Genetic Counselor at whitneyn@uw.edu for more information.