Purpose: The purpose of this study was to document the ability of single-nucleotide polymorphism microarray to identify copy-neutral regions of homozygosity, demonstrate clinical utility of regions of homozygosity, and discuss ethical/legal implications when regions of homozygosity are associated with a parental blood relationship. methods: Study data were compiled from consecutive samples sent to our clinical laboratory over a 3-year period. A cytogenetics database identified patients with at least two regions of homozygosity >10 Mb on two separate chromosomes. A chart review was conducted on patients who met the criteria.