How Does Mode of Inheritance of a Genetic Condition Infl

Human Genome Research

Investigators

Abstract

The mode of inheritance of a genetic condition has long been thought to have not only medical but also social and psychological consequences for affected families. Suppositions about the impact of mode of inheritance have been made based on clinical experience and anecdotal evidence, but remain untested, most likely because of the difficulty in controlling for disease type, severity, course, and resources available when comparing diseases. Chronic granulomatous disease (CGD), a rare immunodeficiency disorder inherited in both an X-linked and autosomal recessive fashion, presents an opportunity to investigate the impact of mode of inheritance in a controlled fashion. Based on qualitative interviews of parents and adolescent sisters of individuals with CGD, we have identified issues salient to families and generated hypotheses about the impact of mode of inheritance. These hypotheses will now be tested via the administration of a mail survey to parents, adult siblings, and adults with CGD. Appropriately modified surveys will be mailed to parents, adult siblings, and adults with Duchenne (DMD) and Becker (BMD) muscular dystrophy (X-linked) and spinal muscular atrophy (SMA) types II and III (autosomal recessive), two similar although not identical neuromuscular diseases, to provide insight into the generalizability of the influence of mode of inheritance. Specifically, we will investigate how mode of inheritance is associated with family members?: 1) understanding of the genetic nature of the conditions and perception of reproductive risk, 2) attitudes toward carrier testing of minors, and 3) feelings of guilt, blame, and stigma by assessing the association of mode of inheritance with each of these independent variables through appropriate bivariate and multivariate analysis. By providing insight into the influence of mode of inheritance, this study will help inform the interactions of health care providers with families affected by CGD, DMD, BMD, and SMA, which can potentially be applied to other X-linked and autosomal recessive conditions. An enhanced understanding of the influence of mode of inheritance will better enable health providers and others to anticipate concerns and questions, address misconceptions, and provide appropriate anticipatory guidance to families. We are in the process of contacting families with MD and SMA by telephone to obtain a brief family history, to answer any questions they may have about participating, and to determine who in their family is eligible and desires to participate. Eligible, interested family members are mailed a questionnaire, followed two weeks later by a reminder letter, and four weeks later by a second copy of the questionnaire if they fail to respond. To date, 77 people have been sent questionnaires at least a month ago. 15/18 questionnaires sent to members of SMA families and 23/59 questionnaires sent to members of MD families have been completed and returned accompanied by a signed informed consent form. As we have nearly completed contacting the families with MD and SMA, we are beginning to contact families with CGD and to mail them questionnaires