The impact of multiplex genetic testing on disease risk perceptions.

This study assessed the effects of multiplex genetic testing on disease risk perceptions among 216 healthy adults. Participants, aged 25-40, were recruited through the Multiplex Initiative, which offered a genetic susceptibility test for eight common diseases. Participants completed baseline telephone and web-based surveys prior to making the testing decision. Three months after the receipt of mailed test results, participants completed a follow-up telephone survey. Risk perceptions for the eight diseases were measured at baseline and follow-up, along with beliefs about genetic causation of those diseases. The main results were: (i) mean risk perceptions were considerably stable from baseline to follow-up; (ii) the best predictors of follow-up risk perceptions were the corresponding baseline perceptions and family history; and (iii) within-individuals, most participants increased or decreased their risk perceptions for specific diseases in concordance with the number of risk markers they carry, their family history and their beliefs about genetic causality of diseases. In conclusion, participants presented a vigilant approach to the interpretation of genetic test results, which provides reassurance with regard to a potential inflation of risk perceptions in the population because of multiplex genetic testing.

Exome Sequencing and High-Density Microarray Testing in Monozygotic Twin Pairs Discordant for Features of VACTERL Association.

Exome sequencing offers an efficient and affordable method to interrogate genetic factors involved in human disease. Performing exome sequencing of monozygotic twins discordant for VACTERL (Vertebral anomalies, Anal atresia, Cardiac malformations, Tracheo-Esophageal fistula, Renal anomalies, and Limb abnormalities) association-type congenital malformations was hypothesized to potentially reveal discordant variants that could demonstrate disease cause(s). After demonstrating monozygosity, we applied high-density microarrays and exome sequencing to 2 twin pairs in which 1 twin had features of VACTERL association while the other was phenotypically normal (demonstrated through comprehensive clinical and radiological evaluation). No obvious discordant genotypic results were found that would explain phenotypic discordance. We conclude that VACTERL association is a complex disease, and while performing microarray analysis and exome sequencing on phenotypically discordant monozygotic twins may hypothetically reveal genetic causes of disorders, challenges remain in applying these methods in this circumstance.

High Intellectual Function in Individuals with Mutation-Positive Microform Holoprosencephaly.

Holoprosencephaly is the most common malformation of the forebrain and typically results in severe neurocognitive impairment with accompanying midline facial anomalies. Holoprosencephaly is heterogeneous and may be caused by chromosome aberrations or environmental factors, occur in the context of a syndrome or be due to heterozygous mutations in over 10 identified genes. The presence of these mutations may result in an extremely wide spectrum of severity, ranging from brain malformations incompatible with life to individuals with normal brain findings and subtle midline facial differences. Typically, clinicians regard intellectual disability as a sign that a parent or relative of a severely affected patient may be a mildly affected mutation 'carrier' with what is termed microform holoprosencephaly. Here we present 5 patients with clear phenotypic signs of microform holoprosencephaly, all of whom have evidence of above-average intellectual function. In 4 of these 5 individuals, the molecular cause of holoprosencephaly has been identified and includes mutations affecting SHH, SIX3, GLI2, and FGF8. This report expands the phenotypic spectrum of holoprosencephaly and is important in the counseling of patient and affected families.

Colonoscopy use following mutation detection in Lynch syndrome: exploring a role for cancer screening in adaptation.

Lynch syndrome (LS) is the most common inherited form of colorectal cancer. Mutation carriers can reduce the morbidity and mortality associated with colorectal cancer through colonoscopy. Theoretical models suggest that such health-related behaviors might also bring psychological benefits. This study assessed whether colonoscopy following mutation detection was associated with the levels of depressive symptoms. Data were obtained from a prospective family cohort study offering genetic services for LS. Participants completed questionnaires prior to the provision of services and 6 months post-receipt of mutation results. One hundred thirty-four (134) persons were identified to carry a mutation and completed both the questionnaires. Main outcome measures were depressive symptoms 6 months post-receipt of test results. Mutation carriers who did not complete a colonoscopy within the 6 months following receipt of results were six times (p < 0.01; odds ratio = 6.06) more likely to report depressive symptoms at a level of clinical importance post-receipt of test results compared to those who did undergo colonoscopy. Facilitating the expeditious use of colonoscopy following mutation detection may benefit newly identified mutation carriers by addressing the objective risks for cancer and moderating underlying emotional distress responses to genetic risk information. Furthermore, depressive symptoms may interfere with behavioral compliance in some patients, suggesting referral to mental health specialists.

Communicating genetic and genomic information: health literacy and numeracy considerations.

Genomic research is transforming our understanding of the role of genes in health and disease. These advances, and their application to common diseases that affect large segments of the general population, suggest that researchers and practitioners in public health genomics will increasingly be called upon to translate genomic information to individuals with varying levels of health literacy and numeracy. This paper discusses the current state of research regarding public understanding of genetics and genomics, the influence of health literacy and numeracy on genetic communication, and behavioral responses to genetic and genomic information. The existing research suggests that members of the general public have some familiarity with genetic and genomic terms but have gaps in understanding of underlying concepts. Findings from the limited research base to date indicate that health literacy affects understanding of print and oral communications about genetic and genomic information. Numeracy is also likely to be an important predictor of being able to understand and apply this information, although little research has been conducted in this area to date. In addition, although some research has examined behavior change in response to the receipt of information about genetic risk for familial disorders and genomic susceptibility to common, complex diseases, the effects of health literacy and numeracy on these responses have not been examined. Potential areas in which additional research is needed are identified and practical suggestions for presenting numeric risk information are outlined. Public health genomics researchers and practitioners are uniquely positioned to engage in research that explores how different audiences react to and use genomic risk information.

The impact of familial environment on depression scores after genetic testing for cancer susceptibility.

The associations between characteristics of family relationships and family trends in cancer worry and the psychological adjustment of recipients of genetic testing for cancer susceptibility were investigated. Data provided by 178 individuals from 24 families with Lynch syndrome who participated in a cohort study investigating psychological and behavioral outcomes of genetic testing were used. Responses from multiple family members were aggregated to construct family trends representing norms and departure from norms in cancer worry. Lower perceived family cohesion at baseline and decrease in this variable at 6 months after receipt of test results were associated with higher depression scores at 12 months. More variability in cancer worry among family members at baseline was also associated with higher depression scores at 12 months. Increase in family conflict was associated with decrease in depression scores among individuals from families with higher levels of cancer worry on average and less variability among the members. Family relationships and family trends in levels of cancer worry may play important roles in the psychological adjustment of genetic test recipients. The findings highlight the complexity of familial environment surrounding individuals that undergo genetic testing and suggest the benefits of considering these factors when providing genetic services.

The Human Genome Project: an update.

The mapping, sequencing, and analysis of the human genome that has occurred during the last decade through the Human Genome Project are providing fundamental advances for basic science and medicine. Genomic information is providing insights into causes of, susceptibility to, and protection from cancer and a host of other diseases. Already, information generated by the Human Genome Project has been incorporated into the care of cancer patients. Perhaps more so than other types of medical information, genetic knowledge can have profound implications for individuals, families, and society. As a result, nursing professionals in clinical and academic settings are being called upon to identify and deliberate medical, social, ethical, and legal issues stemming from Human Genome Project advancements. The purpose of this article is to review the goals and implications of the Human Genome Project to further prepare cancer nurses to actively participate in the deliberations, research, and clinical activities evolving from the Human Genome Project.

Gentamicin treatment of Duchenne and Becker muscular dystrophy due to nonsense mutations.

Aminoglycosides have previously been shown to suppress nonsense mutations, allowing translation of full-length proteins in vitro and in animal models. In the mdx mouse, where muscular dystrophy is due to a nonsense mutation in the dystrophin gene, gentamicin suppressed truncation of the protein and ameliorated the phenotype. A subset of patients with Duchenne and Becker muscular dystrophy similarly possess a nonsense mutation, causing premature termination of dystrophin translation. Four such patients, with various stop codon sequences, were treated once daily with intravenous gentamicin at 7.5 mg/kg/day for 2 weeks. No ototoxicity or nephrotoxicity was detected. Full-length dystrophin was not detected in pre- and post-treatment muscle biopsies.

Psychosocial factors predicting BRCA1/BRCA2 testing decisions in members of hereditary breast and ovarian cancer families.

Although BRCA1/2 testing has increasingly entered clinical practice, much is to be learned about the most effective ways to provide counseling to persons potentially interested in receiving test results. The purpose of this study was to identify factors affecting genetic testing decisions in a cohort of hereditary breast and ovarian cancer (HBOC) families presented with the choice to undergo testing. Relatives in these families are known to carry BRCA1 or BRCA2 mutations. Sociodemographics, personality traits, and family functioning were self-assessed using validated psychometric instruments at baseline. Among 172 individuals who participated in pretest education and counseling, 135 (78%) chose to undergo genetic testing and 37 (22%) chose not to be tested. Individuals who chose to undergo genetic testing were more likely to be older (> or =40 years), to have lower levels of optimism, and to report higher levels of cohesiveness in their families. A better understanding of factors that influence interest in predictive testing may help to inform the counseling that occurs prior to genetic testing.