Seeking to test saliva samples from donors for copy number of a specific gene that is subject to duplication and deletion (and which is hypothesized to predict a specific phenotype shared by participants, who are part of a disease community). In a basic sense, what are the best practices (and alternative approaches) to testing the saliva samples? Am presuming custom assay, to be done by a sequencing provider via multiplex qPCR, comparing yield to a non-varying gene that always has exactly two copies, using a pair of primers for each -- but am unfamiliar with best platforms or even if the above is a sound approach. Seek info to source the work from a standpoint of greater knowledge than currently. Please forgive ignorance; am a nonexpert and part of the disease community that seeks answers and to help others. Advice for assuring a robust result welcome. Thank you in advance for your insights!