Journal of Genetic Counseling

, Volume 22, Issue 2, pp 200–217 | Cite as

“Grasping the Grey”: Patient Understanding and Interpretation of an Intermediate Allele Predictive Test Result for Huntington Disease

  • A. SemakaEmail author
  • L. G. Balneaves
  • M. R. Hayden
Original Research


Since the discovery of the genetic mutation underlying Huntington disease (HD) and the development of predictive testing, the genetics of HD has generally been described as straightforward; an individual receives either mutation-positive or negative predictive test results. However, in actuality, the genetics of HD is complex and a small proportion of individuals receive an unusual predictive test result called an intermediate allele (IA). Unlike mutation-positive or negative results, IAs confer uncertain clinical implications. While individuals with an IA will usually not develop HD, there remains an unknown risk for their children and future generations to develop the disorder. The purpose of this study was to explore how individuals understood and interpreted their IA result. Interviews were conducted with 29 individuals who received an IA result and 8 medical genetics service providers. Interviews were analyzed using the constant comparative method and the coding procedures of grounded theory. Many participants had difficulty “Grasping the Grey” (i.e. understanding and interpreting their IA results) and their family experience, beliefs, expectations, and genetic counseling influenced the degree of this struggle. The theoretical model developed informs clinical practice regarding IAs, ensuring that this unique subset of patients received appropriate education, support, and counseling.


Huntington disease Predictive testing Intermediate alleles Uncertainty Understanding Beliefs Expectations Genetic counseling 



We would like to thank the study participants and medical genetics service providers who shared their time and experiences with us. Funding for this study has been provided by the Canadian Institutes of Health Research. Alicia Semaka is funded by a Senior Trainee Award from the Michael Smith Foundation for Health Research and a Doctoral Award from the Canadian Institutes of Health Research. Lynda Balneaves holds a New Investigator Award from the Canadian Institutes of Health Research. Michael Hayden is a Killam University Professor and holds a Canada Research Chair in Human Genetics and Molecular Medicine.


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Copyright information

© National Society of Genetic Counselors, Inc. 2012

Authors and Affiliations

  1. 1.Department of Medical Genetics, Centre for Molecular Medicine & TherapeuticsUniversity of British ColumbiaVancouverCanada
  2. 2.School of NursingUniversity of British ColumbiaVancouverCanada

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