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One of the most common and unsatisfying situations encountered in medical genetics clinics is the child with multiple congenital anomalies (MCAs) suggestive of an underlying syndrome for whom it is not possible to make a definitive diagnosis. We undertook a qualitative, descriptive study to learn more about the ways in which the lack of a diagnosis affects parental coping and adjustment to their child's special needs. Semistructured interviews were conducted with 29 parents of 16 children born with an unidentified MCA syndrome. Interviews were based on a small number of open-ended questions, with follow-up probing, asking about parents' experiences with seeking a diagnosis, obtaining treatment and special services, explaining their child's problems to others, reproductive decision making, and support group participation. Transcripts of interviews were analyzed to identify the principal themes surrounding parents' beliefs about the significance of diagnostic information. The parents in this study had been aware of their child's anomalies for 2-23 years, and all had sought multiple evaluations to find a diagnosis. A majority of parents were still interested in identifying their child's syndrome, but most felt that their interest in a diagnosis had diminished over time, and some felt that there were benefits in not having this information. We identified six areas where parents claimed a diagnosis would have impact: labels, causes, prognosis, treatment, acceptance, and social support. Significant issues included obtaining special education services, anticipating the child's future and potential medical complications, life expectancy, recurrence risks, finding sources of social support, and ensuring that the child was receiving appropriate treatment. We conclude that the significance of diagnostic information is complex and varies for different parents. Providers should explore the underlying issues associated with a parental quest for a diagnosis in order to identify and address specific concerns. Published 2001 Wiley-Liss, Inc.

Genetic testing has the potential to guide the prevention and treatment of disease in a variety of settings, and recent technical advances have greatly increased our ability to acquire large amounts of genetic data. The interpretation of this data remains challenging, as the clinical significance of genetic variation detected in the laboratory is not always clear. Although regulatory agencies and professional societies provide some guidance regarding the classification, reporting, and long-term follow-up of variants, few protocols for the implementation of these guidelines have been described. Because the primary aim of clinical testing is to provide results to inform medical management, a variant classification program that offers timely, accurate, confident and cost-effective interpretation of variants should be an integral component of the laboratory process. Here we describe the components of our laboratory's current variant classification program (VCP), based on 20 years of experience and over one million samples tested, using the BRCA1/2 genes as a model. Our VCP has lowered the percentage of tests in which one or more BRCA1/2 variants of uncertain significance (VUSs) are detected to 2.1% in the absence of a pathogenic mutation, demonstrating how the coordinated application of resources toward classification and reclassification significantly impacts the clinical utility of testing.

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BACKGROUND: Current estimates of the contribution of large rearrangement (LR) mutations in the BRCA1 (breast cancer 1, early onset) and BRCA2 (breast cancer 2, early onset) genes responsible for hereditary breast and ovarian cancer are based on limited studies of relatively homogeneous patient populations. The prevalence of BRCA1/2 LRs was investigated in 48,456 patients with diverse clinical histories and ancestries, referred for clinical molecular testing for suspicion of hereditary breast and ovarian cancer. METHODS: Sanger sequencing analysis was performed for BRCA1/2 and LR testing for deletions and duplications using a quantitative multiplex polymerase chain reaction assay. Prevalence data were analyzed for patients from different risk and ethnic groups between July 2007 and April 2011. Patients were designated as “high-risk” if their clinical history predicted a high prior probability, wherein LR testing was performed automatically in conjunction with sequencing. “Elective” patients did not meet the high-risk criteria, but underwent LR testing as ordered by the referring health care provider. RESULTS: Overall BRCA1/2 mutation prevalence among high-risk patients was 23.8% versus 8.2% for the elective group. The mutation profile for high-risk patients was 90.1% sequencing mutations versus 9.9% LRs, and for elective patients, 94.1% sequencing versus 5.9% LRs. This difference may reflect the bias in high-risk patients to carry mutations in BRCA1, which has a higher penetrance and frequency of LRs compared with BRCA2. There were significant differences in the prevalence and types of LRs in patients of different ancestries. LR mutations were significantly more common in Latin American/Caribbean patients. CONCLUSIONS: Comprehensive LR testing in conjunction with full gene sequencing is an appropriate strategy for clinical BRCA1/2 analysis.

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IMPORTANCE To date, few studies have examined the extent to which polygenic single-nucleotide variation (SNV) (formerly single-nucleotide polymorphism) scores modify risk for carriers of pathogenic variants (PVs) in breast cancer susceptibility genes. In previous reports, polygenic risk modification was reduced for BRCA1 and BRCA2 PV carriers compared with noncarriers, but limited information is available for carriers of CHEK2, ATM, or PALB2 PVs. OBJECTIVE To examine an 86-SNV polygenic risk score (PRS) for BRCA1, BRCA2, CHEK2, ATM, and PALB2 PV carriers.

Genetic testing for inherited cancer risk is now widely used to target individuals for screening and prevention. However, there is limited evidence available to evaluate the clinical utility of various testing strategies, such as single-syndrome, single-cancer, or pan-cancer gene panels. Here we report on the outcomes of testing with a 25-gene pan-cancer panel in a consecutive series of 252,223 individuals between September 2013 and July 2016. The majority of individuals (92.8%) met testing criteria for Hereditary Breast and Ovarian Cancer (HBOC) and/or Lynch syndrome (LS). Overall, 17,340 PVs were identified in 17,000 (6.7%) of the tested individuals. The PV positive rate was 9.8% among individuals with a personal cancer history, compared to 4.7% in unaffected individuals. PVs were most common in BRCA1/2 (42.2%), other breast cancer (BR) genes (32.9%), and the LS genes (13.2%). Half the PVs identified among individuals who met only HBOC testing criteria were in genes other than BRCA1/2. Similarly, half of PVs identified in individuals who met only LS testing criteria were in non-LS genes. These findings suggest that genetic testing with a pan-cancer panel in this cohort provides improved clinical utility over traditional single-gene or single-syndrome testing.