Prenatal genetic counseling practices regarding recommendations for cancer genetic counseling: A retrospective chart review from two academic institutions.

Prenatal and preconception genetic counselors are trained to take patient pedigrees to evaluate for potential risks for genetic conditions, including hereditary cancer syndromes. However, little research has been published on how often prenatal/preconception genetic counselors provide recommendations for cancer genetic counseling solely based on a family history of cancer. Therefore, this study sought to (a) characterize the types of cancers recognized for a cancer genetic counseling recommendation, (b) analyze appointment indications associated with discussion documentation, and (c) investigate how often National Comprehensive Cancer Center (NCCN) genetic testing criteria for Hereditary Breast and Ovarian Cancer syndrome (HBOC) and Lynch syndrome were met and how often a recommendation for cancer genetic counseling was made. A retrospective chart review and pedigree analysis were performed for prenatal/preconception genetic counseling patients with a family history of cancer seen at two academic institutions between August 10, 2019, and December 1, 2019. In the 170 charts included, a recommendation for cancer genetic counseling was documented in 40% of all genetic counseling summaries and in 59.2% of summaries when NCCN genetic testing criteria for HBOC and/or Lynch syndrome was met. Using chi-squared and logistic regression analysis, these data support that individuals were significantly more likely to receive a recommendation when NCCN genetic testing criteria were met (OR = 5.01, p < .001) or when the family history contained two or more types of cancer (OR = 2.24, p = .02). Overall, this study identified the NCCN genetic testing criteria for HBOC and Lynch syndrome for which recommendations for cancer genetic counseling were commonly missed. This characterization suggests that continuing education for prenatal and preconception genetic counselors on updated NCCN guidelines may be helpful for improving rates of cancer genetic counseling referrals, uptake of genetic testing, and cancer screening recommendations.

Clinical implementation of chromosomal microarray analysis: summary of 2513 postnatal cases.

BACKGROUND: Array Comparative Genomic Hybridization (a-CGH) is a powerful molecular cytogenetic tool to detect genomic imbalances and study disease mechanism and pathogenesis. We report our experience with the clinical implementation of this high resolution human genome analysis, referred to as Chromosomal Microarray Analysis (CMA). METHODS AND FINDINGS: CMA was performed clinically on 2513 postnatal samples from patients referred with a variety of clinical phenotypes. The initial 775 samples were studied using CMA array version 4 and the remaining 1738 samples were analyzed with CMA version 5 containing expanded genomic coverage. Overall, CMA identified clinically relevant genomic imbalances in 8.5% of patients: 7.6% using V4 and 8.9% using V5. Among 117 cases referred for additional investigation of a known cytogenetically detectable rearrangement, CMA identified the majority (92.5%) of the genomic imbalances. Importantly, abnormal CMA findings were observed in 5.2% of patients (98/1872) with normal karyotypes/FISH results, and V5, with expanded genomic coverage, enabled a higher detection rate in this category than V4. For cases without cytogenetic results available, 8.0% (42/524) abnormal CMA results were detected; again, V5 demonstrated an increased ability to detect abnormality. Improved diagnostic potential of CMA is illustrated by 90 cases identified with 51 cryptic microdeletions and 39 predicted apparent reciprocal microduplications in 13 specific chromosomal regions associated with 11 known genomic disorders. In addition, CMA identified copy number variations (CNVs) of uncertain significance in 262 probands; however, parental studies usually facilitated clinical interpretation. Of these, 217 were interpreted as familial variants and 11 were determined to be de novo; the remaining 34 await parental studies to resolve the clinical significance. CONCLUSIONS: This large set of clinical results demonstrates the significantly improved sensitivity of CMA for the detection of clinically relevant genomic imbalances and highlights the need for comprehensive genetic counseling to facilitate accurate clinical correlation and interpretation.