Abstract

Increasingly, genomic analysis is being utilized to diagnose children with developmental delay or dysmorphic facial features suggestive of a congenital disorder. Genetic testing has rapidly evolved, and the genome-wide tests that we use today are significantly different from the more targeted single-gene tests of the last decade. Chromosomal microarray analysis is now a first line test for children with multiple birth defects, children with intellectual impairment, and children with an unusual constellation of symptoms that do not fit with a known disease. There are three types of CMA that are currently clinically available. CMA by oligonucleotide array-based comparative genomic hybridization compares the hybridization signal from the patient's DNA to that of a reference DNA sample for each oligonucleotide on the array. Depending on the specific array, this can range from tens of thousands to hundreds of thousands of oligonucleotides.