Family health beliefs and cascade genetic testing in Asian families with hereditary cancer risk: "Okay, now what?"

The limited literature on Asian family communication of hereditary cancer risk and cascade genetic testing for pathogenic variants (PVs) in BRCA1 and BRCA2 has reported that Asian patients have selective communication of test results and lower cascade testing rates. To better understand the factors that impact communication and cascade testing in Asian families, we conducted an in-depth qualitative study guided by the Health Belief Model. Participants with heterozygous PVs in ATM, BRCA1, BRCA2, CHEK2, or PALB2, who identified their family's origins to an Asian country, were recruited from the Stanford Cancer Genetics Research Database in October-November 2021. Utilizing a constructivist approach, we conducted sixteen semi-structured interviews around family communication and cascade genetic testing. The research team analyzed the transcript data using a reflexive thematic approach. Extensive discussions between the research team resulted in three primary themes presented in this paper: (1) the role of family health beliefs in cascade genetic testing, (2) changes in communication as a result of genetic testing, and (3) genetics providers' role in supporting family discussions on cascade genetic testing. Certain health beliefs, such as perceived susceptibility to cancer and self-efficacy to take action, were co-created by family members and these shared beliefs influenced decisions about genetic testing, family communication, and family support during the cascade genetic testing process. Participants shared strategies for how genetics providers can prepare Asian patients for more effective conversations with relatives and better address potential testing barriers by tailoring information and providing anticipatory guidance. This study represents an important contribution to the literature about cascade testing among an underrepresented group. Shared family health beliefs about genetic testing may be particularly relevant for this community and these findings can inform strategies to increase cascade genetic testing in Asian families.

Preventive drugs for Huntington's disease: A choice-based conjoint survey of patient preferences.

Introduction: This research examined the perspective of the Huntington's disease (HD) community regarding the use of predictive biomarkers as endpoints for regulatory approval of therapeutics to prevent or delay the onset of clinical HD in asymptomatic mutation carriers. Methods: An online, choice-based conjoint survey was shared with HD community members including untested at-risk individuals, presymptomatic mutation carriers, and symptomatic individuals. Across 15 scenarios, participants chose among two proposed therapies with differing degrees of biomarker improvement and side effects or a third option of no treatment. Results: Two hundred and thirty-eight responses were received. Attributes reflecting biomarker efficacy (e.g., prevention of brain atrophy on magnetic resonance imaging, reduced mutant huntingtin, or reduced inflammation biomarkers) had 3- to 7-fold greater importance than attributes representing side effects (e.g., increased risk of heart disease, cancer, and stroke over 20 years) and were more influential in directing choice of treatments. Reduction in mutant huntingtin protein was the most valued attribute overall. Multinomial logit model simulations based on survey responses demonstrated high interest among respondents (87-99% of the population) for drugs that might prevent or delay HD solely based upon biomarker evidence, even at the risk of serious side effects. Conclusion: These results indicate a strong desire among members of the HD community for preventive therapeutics and a willingness to accept significant side effects, even before the drug has been shown to definitively delay disease onset if the drug improves biomarker evidence of HD progression. Preferences of the HD community should inform regulatory policies for approving preventive therapies.

Physician-directed genetic screening to evaluate personal risk for medically actionable disorders: a large multi-center cohort study.

BACKGROUND: The use of proactive genetic screening for disease prevention and early detection is not yet widespread. Professional practice guidelines from the American College of Medical Genetics and Genomics (ACMG) have encouraged reporting pathogenic variants that confer personal risk for actionable monogenic hereditary disorders, but only as secondary findings from exome or genome sequencing. The Centers for Disease Control and Prevention (CDC) recognizes the potential public health impact of three Tier 1 actionable disorders. Here, we report results of a large multi-center cohort study to determine the yield and potential value of screening healthy individuals for variants associated with a broad range of actionable monogenic disorders, outside the context of secondary findings. METHODS: Eligible adults were offered a proactive genetic screening test by health care providers in a variety of clinical settings. The screening panel based on next-generation sequencing contained up to 147 genes associated with monogenic disorders within cancer, cardiovascular, and other important clinical areas. Sequence and intragenic copy number variants classified as pathogenic, likely pathogenic, pathogenic (low penetrance), or increased risk allele were considered clinically significant and reported. Results were analyzed by clinical area and severity/burden of disease using chi-square tests without Yates' correction. RESULTS: Among 10,478 unrelated adults screened, 1619 (15.5%) had results indicating personal risk for an actionable monogenic disorder. In contrast, only 3.1 to 5.2% had clinically reportable variants in genes suggested by the ACMG version 2 secondary findings list to be examined during exome or genome sequencing, and 2% had reportable variants related to CDC Tier 1 conditions. Among patients, 649 (6.2%) were positive for a genotype associated with a disease of high severity/burden, including hereditary cancer syndromes, cardiovascular disorders, or malignant hyperthermia susceptibility. CONCLUSIONS: This is one of the first real-world examples of specialists and primary care providers using genetic screening with a multi-gene panel to identify health risks in their patients. Nearly one in six individuals screened for variants associated with actionable monogenic disorders had clinically significant results. These findings provide a foundation for further studies to assess the role of genetic screening as part of regular medical care.

Understanding variants of uncertain significance in the era of multigene panels: Through the eyes of the patient.

Variants of uncertain significance (VUSs) are often disclosed to patients despite ambiguous association with disease risk and lack of clinical actionability. It is important to understand how patients understand a VUS result, but few studies have assessed this. Our qualitative study explored patient recall, reaction to, and interpretation of a VUS in the context of multigene panels. We conducted 11 semi-structured phone interviews with adults who had a VUS identified on multigene panel testing in a hereditary oncology clinic, with questions focusing on the VUS result, personal and family history, and motivations for and expectations of genetic testing. Transcripts were coded iteratively, using both deductive and inductive codes. Overall, participants usually recalled that they had a VUS, despite variation in the vocabulary used. Participants responded both emotionally and intellectually to receiving information about having a VUS, which was often a result of their expectations and motivations prior to testing. Overall, participants understood the lack of clinical significance of a VUS, yet often interpreted the etiologic significance of a VUS within the context of the personal and family history. Our study provides insight into a process by which patients translate uncertain genetic testing results into a construct that fits within their current belief framework and which may be facilitated by a genetic counselor.

Use of genetic risks in pediatric organ transplantation listing decisions: A national survey.

There is a limited supply of organs for all those who need them for survival. Thus, careful decisions must be made about who is listed for transplant. Studies show that manifesting genetic disease can impact listing eligibility. What has not yet been studied is the impact genetic risks for future disease have on a patient's chance to be listed. Surveys were emailed to 163 pediatric liver, heart, and kidney transplant programs across the United States to elicit views and experiences of key clinicians regarding each program's use of genetic risks (ie, predispositions, positive predictive testing) in listing decisions. Response rate was 42%. Sixty-four percent of programs have required genetic testing for specific indications prior to listing decisions. Sixteen percent have required it without specific indications, suggesting that genetic testing may be used to screen candidates. Six percent have chosen not to list patients with secondary findings or family histories of genetic conditions. In hypothetical scenarios, programs consider cancer predispositions and adult-onset neurological conditions to be relative contraindications to listing (61%, 17%, and 8% depending on scenario), and some consider them absolute contraindications (5% and 3% depending on scenario). Only 3% of programs have formal policies for these scenarios, but all consult genetic specialists at least "sometimes" for results interpretation. Our study reveals that pediatric transplant programs are using future onset genetic risks in listing decisions. As genetic testing is increasingly adopted into pediatric medicine, further study is needed to prevent possible inappropriate use of genetic information from impacting listing eligibility.

MACF1 Mutations Encoding Highly Conserved Zinc-Binding Residues of the GAR Domain Cause Defects in Neuronal Migration and Axon Guidance.

To date, mutations in 15 actin- or microtubule-associated genes have been associated with the cortical malformation lissencephaly and variable brainstem hypoplasia. During a multicenter review, we recognized a rare lissencephaly variant with a complex brainstem malformation in three unrelated children. We searched our large brain-malformation databases and found another five children with this malformation (as well as one with a less severe variant), analyzed available whole-exome or -genome sequencing data, and tested ciliogenesis in two affected individuals. The brain malformation comprised posterior predominant lissencephaly and midline crossing defects consisting of absent anterior commissure and a striking W-shaped brainstem malformation caused by small or absent pontine crossing fibers. We discovered heterozygous de novo missense variants or an in-frame deletion involving highly conserved zinc-binding residues within the GAR domain of MACF1 in the first eight subjects. We studied cilium formation and found a higher proportion of mutant cells with short cilia than of control cells with short cilia. A ninth child had similar lissencephaly but only subtle brainstem dysplasia associated with a heterozygous de novo missense variant in the spectrin repeat domain of MACF1. Thus, we report variants of the microtubule-binding GAR domain of MACF1 as the cause of a distinctive and most likely pathognomonic brain malformation. A gain-of-function or dominant-negative mechanism appears likely given that many heterozygous mutations leading to protein truncation are included in the ExAC Browser. However, three de novo variants in MACF1 have been observed in large schizophrenia cohorts.

De Novo Missense Variants in TRAF7 Cause Developmental Delay, Congenital Anomalies, and Dysmorphic Features.

TRAF7 is a multi-functional protein involved in diverse signaling pathways and cellular processes. The phenotypic consequence of germline TRAF7 variants remains unclear. Here we report missense variants in TRAF7 in seven unrelated individuals referred for clinical exome sequencing. The seven individuals share substantial phenotypic overlap, with developmental delay, congenital heart defects, limb and digital anomalies, and dysmorphic features emerging as key unifying features. The identified variants are de novo in six individuals and comprise four distinct missense changes, including a c.1964G>A (p.Arg655Gln) variant that is recurrent in four individuals. These variants affect evolutionarily conserved amino acids and are located in key functional domains. Gene-specific mutation rate analysis showed that the occurrence of the de novo variants in TRAF7 (p = 2.6 × 10-3) and the recurrent de novo c.1964G>A (p.Arg655Gln) variant (p = 1.9 × 10-8) in our exome cohort was unlikely to have occurred by chance. In vitro analyses of the observed TRAF7 mutations showed reduced ERK1/2 phosphorylation. Our findings suggest that missense mutations in TRAF7 are associated with a multisystem disorder and provide evidence of a role for TRAF7 in human development.

Germline Loss-of-Function Mutations in EPHB4 Cause a Second Form of Capillary Malformation-Arteriovenous Malformation (CM-AVM2) Deregulating RAS-MAPK Signaling.

BACKGROUND: Most arteriovenous malformations (AVMs) are localized and occur sporadically. However, they also can be multifocal in autosomal-dominant disorders, such as hereditary hemorrhagic telangiectasia and capillary malformation (CM)-AVM. Previously, we identified RASA1 mutations in 50% of patients with CM-AVM. Herein we studied non-RASA1 patients to further elucidate the pathogenicity of CMs and AVMs. METHODS: We conducted a genome-wide linkage study on a CM-AVM family. Whole-exome sequencing was also performed on 9 unrelated CM-AVM families. We identified a candidate gene and screened it in a large series of patients. The influence of several missense variants on protein function was also studied in vitro. RESULTS: We found evidence for linkage in 2 loci. Whole-exome sequencing data unraveled 4 distinct damaging variants in EPHB4 in 5 families that cosegregated with CM-AVM. Overall, screening of EPHB4 detected 47 distinct mutations in 54 index patients: 27 led to a premature stop codon or splice-site alteration, suggesting loss of function. The other 20 are nonsynonymous variants that result in amino acid substitutions. In vitro expression of several mutations confirmed loss of function of EPHB4. The clinical features included multifocal CMs, telangiectasias, and AVMs. CONCLUSIONS: We found EPHB4 mutations in patients with multifocal CMs associated with AVMs. The phenotype, CM-AVM2, mimics RASA1-related CM-AVM1 and also hereditary hemorrhagic telangiectasia. RASA1-encoded p120RASGAP is a direct effector of EPHB4. Our data highlight the pathogenetic importance of this interaction and indicts EPHB4-RAS-ERK signaling pathway as a major cause for AVMs.