Attitudes and interest in incorporating BRCA1/2 cancer susceptibility testing into reproductive carrier screening for Ashkenazi Jewish men and women.

Pathogenic variants in the BRCA1 and BRCA2 (BRCA1/2) genes are associated with elevated cancer risks in men and women. Due to a founder effect, Ashkenazi Jewish individuals are at higher risk for carrying three specific BRCA1/2 pathogenic variants. There have been recent calls for population screening in this population because many carriers do not have family histories suggestive of hereditary cancer. One approach could be to integrate optional BRCA1/2 testing into routinely offered reproductive carrier screening for recessive and X-linked disorders. However, the differing goals of these types of testing (i.e., personal health risks versus family planning) raise questions about the implications for patient education and informed consent. To this end, we aimed to determine interest, attitudes, and preferences regarding integrating such testing by electronically surveying 331 Ashkenazi Jewish participants in JScreen - a national, not-for-profit, at-home carrier screening program focused on genetic risks in Jewish communities. We found that while 41% of participants had plans to pursue BRCA1/2 testing, 93% would have opted for such testing if offered as an add-on to reproductive carrier screening. This was particularly true of those with higher perceived cancer risk and more positive attitudes toward genetic testing. With respect to preferences about delivery of this service, more than 85% of participants preferred remote (telephone, print, or web-based) genetic education rather than traditional genetic counseling. These results suggest that offering optional BRCA1/2 testing within the context of reproductive carrier screening might provide opportunities for cancer prevention without overburdening scarce genetic counseling resources.

Evaluating the experiences of individuals with personal health risks identified through expanded carrier screening.

Expanded carrier screening (ECS) is used to identify individuals and couples at risk for having children with recessive or X-linked genetic conditions; however, personal health risks (PHR) can also be identified through this testing. There is limited data on how genetic counseling regarding PHR from ECS is perceived by the individual, or how they use this information. This study quantitatively surveyed individuals identified with these risks between September 2013 and March 2020. The 30-item survey included the validated Genomics Outcome Scale Short Form, the validated Genetic Counseling Satisfaction Scale, and original questions. Survey topics included pre-test knowledge of the possibility of discovering PHR through testing, satisfaction with pre-test education that addresses potential risks, perceived severity of PHR, empowerment by and understanding of information, anxiety levels related to their PHR, perceived genetic counseling support, and satisfaction with telehealth. A total of 416 completed surveys were analyzed using descriptive statistics, and linear and logistic regressions. The majority of participants were satisfied or extremely satisfied with pre-test education (n = 328; 78.8%) and telehealth (n = 329; 79.1%). However, more participants who were aware of the possibility of identifying PHR through ECS prior to testing were satisfied with pre-test education compared to those who were not aware. Additionally, a lack of prior awareness of PHR was associated with lower empowerment scores (p = .004). Those who were highly satisfied with genetic counseling were more likely to feel empowered and understand the information presented (p = .001). The majority of individuals used their PHR information following their results appointment (n = 391; 94.0%). The results of this study suggest that receiving PHR information was useful and was positively influenced by both pre-test education and the genetic counseling process.

Screening for Tay-Sachs disease carriers by full-exon sequencing with novel variant interpretation outperforms enzyme testing in a pan-ethnic cohort.

BACKGROUND: Pathogenic variants in HEXA that impair ß-hexosaminidase A (Hex A) enzyme activity cause Tay-Sachs Disease (TSD), a severe autosomal-recessive neurodegenerative disorder. Hex A enzyme analysis demonstrates near-zero activity in patients affected with TSD and can also identify carriers, whose single functional copy of HEXA results in reduced enzyme activity relative to noncarriers. Although enzyme testing has been optimized and widely used for carrier screening in Ashkenazi Jewish (AJ) individuals, it has unproven sensitivity and specificity in a pan-ethnic population. The ability to detect HEXA variants via DNA analysis has evolved from limited targeting of a few ethnicity-specific variants to next-generation sequencing (NGS) of the entire coding region coupled with interpretation of any discovered novel variants. METHODS: We combined results of enzyme testing, retrospective computational analysis, and variant reclassification to estimate the respective clinical performance of TSD screening via enzyme analysis and NGS. We maximized NGS accuracy by reclassifying variants of uncertain significance and compared to the maximum performance of enzyme analysis estimated by calculating ethnicity-specific frequencies of variants known to yield false-positive or false-negative enzyme results (e.g., pseudodeficiency and B1 alleles). RESULTS: In both AJ and non-AJ populations, the estimated clinical sensitivity, specificity, and positive predictive value were higher by NGS than by enzyme testing. The differences were significant for all comparisons except for AJ clinical sensitivity, where NGS exceeded enzyme testing, but not significantly. CONCLUSIONS: Our results suggest that performance of an NGS-based TSD carrier screen that interrogates the entire coding region and employs novel variant interpretation exceeds that of Hex A enzyme testing, warranting a reconsideration of existing guidelines.

Patients' reactions and follow-up testing decisions related to Tay-Sachs (HEXA) variants of uncertain significance results.

JScreen is a national public health initiative based out of Emory University that provides reproductive carrier screening through an online portal and follow-up genetic counseling services. In 2014, JScreen began reporting to patients variants of uncertain significance (VUSs) in the gene that causes Tay-Sachs disease (HEXA). Genetic counseling was provided to discuss the VUS and patients were offered hexosaminidase A (HEXA) blood enzyme testing to assist with VUS reclassification. To identify patient reactions and factors influencing their follow-up testing decisions after receiving these results, we conducted a retrospective quantitative study by administering online surveys to 62 patients with HEXA VUSs. Participants who pursued enzyme testing and those who did not both experienced low levels of distress when receiving the VUS results. Perceptions of HEXA carrier status after genetic counseling, decisional conflict levels, plans to have children in the near future, time available to pursue enzyme testing, and eligibility for research were significant factors influencing decision-making to pursue or not pursue enzyme testing. Genetic counseling played an important role in helping patients understand the VUS and follow-up testing options. When discussing VUSs with patients, it would be beneficial for genetic counselors to focus on the patient's perception of the VUS, anxiety related to the uncertainty of their results, and follow-up options, when available.

Gaucher disease: in vivo evidence for allele dose leading to neuronopathic and nonneuronopathic phenotypes.

Gaucher disease, a common lysosomal storage disorder, is associated with mutations at the acid beta-glucosidase (GCase) locus. Two affected individuals are described to share a common mutant allele, but manifest different clinical categorical phenotypes. A 57-year-old female, with Gaucher disease type 1 and Cherokee ancestry, was homozygous for a rare mutant allele encoding Lys79Asn (K79N). A 2-year-old Caucasian male, with Gaucher disease type 3 and Cherokee ancestry, was a heteroallelic homozygote for this same allele (K79N) and a novel complex mutation (null allele). The shared alleles were identical as determined by complete gene sequencing, suggesting a founder effect. The discrepant phenotypes (types 1 and 3) in these two patients provide support for a threshold of residual activity necessary to "protect" the central nervous system (CNS) from the pathogenic effects of Gaucher disease, indicating an allele dose-effect. Designation of genotype associations with specific phenotypes must be assessed with this perspective.

Cessation of enzyme replacement therapy in Gaucher disease.

PURPOSE: Enzyme replacement therapy (ERT) is a promising therapeutic intervention for lysosomal storage diseases. Posttranslationally engineered human beta-glucocerebrosidase (Ceredase/Cerezyme) is commercially available and is the standard ERT for Type I Gaucher disease. Cessation of therapy is sometimes necessary for personal or financial reasons, but the consequences of discontinuation are unknown. This study reports results of discontinuing therapy in four patients with Type I Gaucher disease with different genotypes and varying degrees of clinical involvement. METHODS: Patient genotypes were as follows: N370S/L444P (Patients 1 and 2), K79N/K79N (Patient 3), and N370S/N370S (Patient 4). All were evaluated before, during, and after withdrawal from ERT. Patients 1, 2, and 3 were studied after reinstituting ERT. The following parameters were documented at 3- to 12-month intervals in all patients: hemoglobin, platelet count, angiotensin-converting enzyme, spleen volume, liver volume, femoral magnetic resonance imaging, bone density, and urinary pyridinium crosslinks. RESULTS: After cessation of therapy, Patients 1, 2, and 3 had more dramatic regression in hematological and visceral parameters than Patient 4 and required reinstitution of ERT within 2 years. All three patients recovered posttreatment status within 4 years of reinstituting ERT. Patient 4 remained stable 6 years after cessation of ERT. CONCLUSIONS: Regression of disease status in patients with Type I Gaucher disease after cessation of ERT conformed to the genotype-phenotype relationships of disease onset. Careful monitoring and reinstitution of ERT enabled previously attained treatment status.