Myra J. Wick

Long QT Syndrome–Associated Mutations in Intrauterine Fetal Death

IMPORTANCE Intrauterine fetal death or stillbirth occurs in approximately 1 out of every 160 pregnancies and accounts for 50% of all perinatal deaths. Postmortem evaluation fails to elucidate an underlying cause in many cases. Long QT syndrome (LQTS) may contribute to this problem. OBJECTIVE To determine the spectrum and prevalence of mutations in the 3 most common LQTS susceptible genes (KCNQ1, KCNH2, and SCN5A) for a cohort of unexplained cases. DESIGN, SETTING, AND PATIENTS In this case series, retrospective postmortem genetic testing was conducted on a convenience sample of 91 unexplained intrauterine fetal deaths (mean [SD] estimated gestational age at fetal death, 26.3 [8.7] weeks) that were collected from 2006-2012 by the Mayo Clinic, Rochester, Minnesota, or the Fondazione IRCCS Policlinico San Matteo, Pavia, Italy. More than 1300 ostensibly healthy individuals served as controls. In addition, publicly available exome databases were assessed for the general population frequency of identified genetic variants. MAIN OUTCOMES AND MEASURES Comprehensive mutational analyses of KCNQ1 (KV7.1, LQTS type 1), KCNH2 (HERG/KV11.1, LQTS type 2), and SCN5A (NaV1.5, LQTS type 3) were performed using denaturing high-performance liquid chromatography and direct DNA sequencing on genomic DNA extracted from decedent tissue. Functional analyses of novel mutations were performed using heterologous expression and patch-clamp recording. RESULTS The 3 putative LQTS susceptibility missense mutations (KCNQ1, p.A283T; KCNQ1, p.R397W; and KCNH2 [1b], p.R25W), with a heterozygous frequency of less than 0.05% in more than 10 000 publicly available exomes and absent in more than 1000 ethnically similar control patients, were discovered in 3 intrauterine fetal deaths (3.3% [95% CI, 0.68%-9.3%]). Both KV7.1-A283T (16-week male) and KV7.1-R397W (16-week female) mutations were associated with marked KV7.1 loss-of-function consistent with in utero LQTS type 1, whereas the HERG1b-R25W mutation (33.2-week male) exhibited a loss of function consistent with in utero LQTS type 2. In addition, 5 intrauterine fetal deaths hosted SCN5A rare nonsynonymous genetic variants (p.T220I, p.R1193Q, involving 2 cases, and p.P2006A, involving 2 cases) that conferred in vitro electrophysiological characteristics consistent with potentially proarrhythmic phenotypes. CONCLUSIONS AND RELEVANCE In this molecular genetic evaluation of 91 cases of intrauterine fetal death, missense mutations associated with LQTS susceptibility were discovered in 3 cases (3.3%) and overall, genetic variants leading to dysfunctional LQTS-associated ion channels in vitro were discovered in 8 cases (8.8%). These preliminary findings may provide insights into mechanisms of some cases of stillbirth.

Clinical Characteristics of Ovarian Cancer Classified by BRCA1, BRCA2, and RAD51C Status

We evaluated homologous recombination deficient (HRD) phenotypes in epithelial ovarian cancer (EOC) considering BRCA1, BRCA2, and RAD51C in a large well-annotated patient set. We evaluated EOC patients for germline deleterious mutations (n = 899), somatic mutations (n = 279) and epigenetic alterations (n = 482) in these genes using NGS and genome-wide methylation arrays. Deleterious germline mutations were identified in 32 (3.6%) patients for BRCA1, in 28 (3.1%) for BRCA2 and in 26 (2.9%) for RAD51C. Ten somatically sequenced patients had deleterious alterations, six (2.1%) in BRCA1 and four (1.4%) in BRCA2. Fifty two patients (10.8%) had methylated BRCA1 or RAD51C. HRD patients with germline or somatic alterations in any gene were more likely to be high grade serous, have an earlier diagnosis age and have ovarian and/or breast cancer family history. The HRD phenotype was most common in high grade serous EOC. Identification of EOC patients with an HRD phenotype may help tailor specific therapies.

Outcome of Whole Exome Sequencing for Diagnostic Odyssey Cases of an Individualized Medicine Clinic: The Mayo Clinic Experience

OBJECTIVE To describe the experience and outcome of performing whole-exome sequencing (WES) for resolution of patients on a diagnostic odyssey in the first 18 months of an individualized medicine clinic (IMC). PATIENTS AND METHODS The IMC offered WES to physicians of Mayo Clinic practice for patients with suspected genetic disease. DNA specimens of the proband and relatives were submitted to WES laboratories. We developed the Genomic Odyssey Board with multidisciplinary expertise to determine the appropriateness for IMC services, review WES reports, and make the final decision about whether the exome findings explain the disease. This study took place from September 30, 2012, to March 30, 2014. RESULTS In the first 18 consecutive months, the IMC received 82 consultation requests for patients on a diagnostic odyssey. The Genomic Odyssey Board deferred 7 cases and approved 75 cases to proceed with WES. Seventy-one patients met with an IMC genomic counselor. Fifty-one patients submitted specimens for WES testing, and the results have been received for all. There were 15 cases in which a diagnosis was made on the basis of WES findings; thus, the positive diagnostic yield of this practice was 29%. The mean cost per patient for this service was approximately

Challenging and complex decisions in the management of the BRCA mutation carrier.

8000. Medicaid supported 27% of the patients, and 38% of patients received complete or partial insurance coverage. CONCLUSION The significant diagnostic yield, moderate cost, and notable health marketplace acceptance for WES compared with conventional genetic testing make the former method a rational diagnostic approach for patients on a diagnostic odyssey.

De novo 16p deletion: ATR‐16 syndrome

Women afflicted by the hereditary breast and ovarian cancer syndrome face complex decisions regarding medical interventions aimed at reducing their risk of ovarian and breast cancer, interventions which in turn may interfere with their fertility and cause early menopause. This review addresses selected topics of importance and controversy in the management of the BRCA mutation carrier, such as psychological well-being and quality of life, breast and ovarian cancer screening, risk-reducing interventions for breast cancer and ovarian cancer, the issue of hysterectomy at the time of the risk-reducing salpingo-oophorectomy, health consequences of early surgical menopause, and safety of hormonal therapy after oophorectomy. The information presented is based on an extensive review of the literature on the selected topics and on the expertise of our multidisciplinary team.

Predicting Vaginal Birth after Cesarean Section: A Cohort Study

We describe a child with alpha-thalassemia ascertained by newborn screening. Evaluation at 9 months of age showed minor anomalies and developmental delay. Chromosomal analysis demonstrated a de novo deletion of the most distal portion of the short arm of chromosome 16, which contains the alpha-globin genes. Analysis of the alpha-globin locus by Southern blot analysis did not demonstrate altered band sizes at this locus; however, analysis of the films using densitometry confirmed hemizygosity. This is the fifth reported case of the ATR-16 syndrome (alpha-thalassemia retardation-16) not complicated by duplication or deletion of other chromosomes.

Primary appendiceal mucinous adenocarcinoma in two first-degree relatives: case report and review

Objective: To develop a model to predict vaginal birth after cesarean (VBAC) in our population and to compare the accuracy of this model to the accuracy of a previously published widely used model. Materials and Methods: Women attempting trial of labor after cesarean delivery (TOLAC) at our institution from January 1, 2000 through May 30, 2010 were evaluated for inclusion. Demographic and clinical data were collected. Associations of these characteristics with VBAC were evaluated with univariate and multivariate logistic regression. We critically compared the accuracy of the resulting model to a previously published widely utilized model for predicting VBAC. Results: A total of 2,635 deliveries with at least 1 prior cesarean delivery were identified. TOLAC was attempted in 599 (22.7%) and resulted in 456 VBACs (76.0%) and 143 repeat cesareans (24.0%). VBAC success was independently associated with age <30 years, a body mass index <30, prior vaginal delivery, prior VBAC, and absence of a recurrent indication for cesarean. This model provided a range of successful probability of VBAC (38-98%) with an area under the receiver operating characteristic curve of 0.723. Conclusions: This study provides an accurate and simple model that can be utilized to guide decisions related to TOLAC.

Offering Prenatal Screening in the Age of Genomic Medicine: A Practical Guide

Carcinomas of the appendix are exceedingly rare tumors and have an annual age-adjusted incidence of around 0.4 cases per 100,000. Appendiceal adenocarcinoma accounts for < 0.5% of all gastrointestinal neoplasms and, of these, mucinous adenocarcinomas account for the majority. Published accounts of familial instances of primary appendiceal tumors are strikingly rare. We report two siblings who both developed primary mucinous adenocarcinomas. A genetics evaluation was conducted to determine if there was a recognizable underlying single gene disorder; no DNA mismatch repair defect was evident, and no other diagnosis was apparent. A review of appendiceal cancers seen at Mayo Clinic from l997 to the present was conducted to search for additional familial cases. Among 316 cases of primary appendiceal cancer of any histologic type, this sib pair was the only family reporting a second affected family member. The occurrence of appendiceal cancer in siblings may represent a random occurrence. An exceedingly rare predisposition syndrome cannot be ruled out.

Functional characterization of a GFAP variant of uncertain significance in an Alexander disease case within the setting of an individualized medicine clinic.

AIMS In September, 2015, Mayo Clinic convened a panel of national thought leaders on prenatal screening, medical genetics, and obstetrics and gynecology practice. RESULTS During the 2-day symposium, participants discussed the implications of the shift toward broader prenatal screening using cell-free placental DNA in maternal serum (cfDNA screening). Key topics included challenges around the pace of change in the prenatal screening market, uncertainty around reimbursement, meeting the need for patient counseling, and potential challenges in interpreting and returning cfDNA screening results. INNOVATION Here, we describe the challenges discussed and offer clinical recommendations for practices who are working to meet them. CONCLUSION As the spread of prenatal genetic screening continues, providers will increasingly need to update their practice to accommodate new screening modalities.

Noninvasive Prenatal Genetic Screening Using Cell-free DNA

A de novo GFAP variant, p.R376W, was identified in a child presenting with hypotonia, developmental delay, and abnormal brain MRI. Following the 2015 ACMG variant classification guidelines and the functional studies showing protein aggregate formation in vitro, p.R376W should be classified as a pathogenic variant, causative for Alexander disease.