Chapter 25, Problem 1CS

At an interview with a genetic counselor, a couple with a severely asthmatic child learned that asthma is a complex disorder involving many genetic loci. The counselor explained that a method called whole genome sequencing (WGS) is now widely used in diagnosing and treating traits controlled by multiple loci and, in this case, could provide information to devise an effective therapy for their child. However, the parents were warned that because their child’s entire genome was to be sequenced, information unrelated to asthma, but with potentially serious health consequences, might be discovered. After permission was granted, genome analysis created a panel of loci for therapy design. The analysis also revealed that the child carried two copies of an allele conferring an increased risk for Alzheimer disease. One copy of this allele increases the risk 4-fold; two copies raise the risk to 12-fold. Even though the child and both parents are at risk, current guidelines do not require that this finding be disclosed because it is unrelated to the primary reason for undertaking WGS. Knowing that disclosure was not legally required, but feeling she may have an ethical responsibility to divulge this information, the counselor was conflicted regarding how to proceed.

Based on the outcome of the WGS, what can the counselor tell the parents about their own risk of developing Alzheimer disease?