Genetic variants associated with breast cancer risk for Ashkenazi Jewish women with strong family histories but no identifiable BRCA1/2 mutation.

The ability to establish genetic risk models is critical for early identification and optimal treatment of breast cancer. For such a model to gain clinical utility, more variants must be identified beyond those discovered in previous genome-wide association studies (GWAS). This is especially true for women at high risk because of family history, but without BRCA1/2 mutations. This study incorporates three datasets in a GWAS analysis of women with Ashkenazi Jewish (AJ) homogeneous ancestry. Two independent discovery cohorts comprised 239 and 238 AJ women with invasive breast cancer or preinvasive ductal carcinoma in situ and strong family histories of breast cancer, but lacking the three BRCA1/2 founder mutations, along with 294 and 230 AJ controls, respectively. An independent, third cohort of 203 AJ cases with familial breast cancer history and 263 healthy controls of AJ women was used for validation. A total of 19 SNPs were identified as associated with familial breast cancer risk in AJ women. Among these SNPs, 13 were identified from a panel of 109 discovery SNPs, including an FGFR2 haplotype. In addition, six previously identified breast cancer GWAS SNPs were confirmed in this population. Seven of the 19 markers were significant in a multivariate predictive model of familial breast cancer in AJ women, three novel SNPs [rs17663555(5q13.2), rs566164(6q21), and rs11075884(16q22.2)], the FGFR2 haplotype, and three previously published SNPs [rs13387042(2q35), rs2046210(ESR1), and rs3112612(TOX3)], yielding moderate predictive power with an area under the curve (AUC) of the ROC (receiver-operator characteristic curve) of 0.74. Population-specific genetic variants in addition to variants shared with populations of European ancestry may improve breast cancer risk prediction among AJ women from high-risk families without founder BRCA1/2 mutations.

Best practices: antenatal screening for common genetic conditions other than aneuploidy.

PURPOSE OF REVIEW: Carrier screening aims to identify asymptomatic heterozygotes of heritable disorders and has a vital, ever-changing role in its application to the prenatal detection of disease. An explosion of new technologies for the identification of single-gene disorders challenges our ability to evaluate each individual test prior to its introduction into the private and public sectors. RECENT FINDINGS: The efficacy of carrier screening is dependent on several factors including the validity of the test, the incidence of disease within the community, and as many genetic disorders segregate along ethnic and racial lines, which populations should be offered testing. The difficulties in evaluating prenatal screening programs are highlighted by the recent conflicting recommendations from the American College of Medical Genetics and the American Congress of Obstetrics and Gynecology over several single-gene disorders. In addition, changes in the recommendation for universal versus risk-based screening for ethnically segregated disorders remain controversial. These conflicts have major impacts in the provision of genetic counseling in the prenatal outpatient setting. SUMMARY: We will evaluate current and proposed screening protocols for several single-gene disorders, and comment on universal versus ethnic-based screening. Our objective is to develop guidelines for genetic screening in the antenatal outpatient setting.

Chromosomal microarray in prenatal diagnosis: case studies and clinical challenges.

Chromosomal microarray analysis (CMA) is a diagnostic tool used in the evaluation of pediatric patients with congenital anomalies or developmental and intellectual disability. In both the pediatric and prenatal patient population, CMA has been shown to have a higher detection rate of chromosomal abnormalities than conventional karyotype alone. Currently, the diagnostic yield of prenatal CMA is highest when applied to the evaluation of a fetus with multiple ultrasound anomalies. Challenges arise when CMA yields isolated findings not associated with a phenotype on ultrasound or variants of uncertain significance, which warrants evaluation of the risks, benefits, limitations and optimal incorporation of CMA into prenatal care. The clinical cases presented here will be used to illustrate these issues.

Prenatal screening for fragile x: carriers, controversies, and counseling.

In addition to causing developmental disability in future offspring, fragile X carrier status has important reproductive and mental health implications for the individual being tested. Accordingly, prenatal carrier screening and diagnosis using DNA-based molecular methods has become crucial in early detection, intervention, and family planning. Although the list of known genetic disorders is growing daily, controversy remains over who should be tested for fragile X. FMR1 gene mutations can result in inherited intellectual disability, infertility, and neurodegeneration syndromes that are encountered by clinicians in a variety of settings. Patients and clinicians are still largely unfamiliar with this disorder, its complicated inheritance, and its heterogeneous phenotype. Debate continues over who should be offered prenatal carrier screening. As more disease screening is offered, pretest counseling will become only more complex and clinicians will further struggle to balance the needs of the individual and allocation of public health resources.

Sibling and self ovum donation for sisters with an intermediate FMR1 mutation: what's a program to do?

OBJECTIVE: To increase awareness of the unique clinical and ethical considerations invoked by the request of a patient with premature ovarian failure (POF) and her nulliparous sister, both with intermediate-size mutations in fragile X mental retardation 1 (FMR1), to pursue sibling ovum donation. DESIGN: Case report. SETTING: Academic medical center. PATIENT(S): A 32-year-old woman with POF and her 26-year-old sister with occult diminished ovarian reserve, both of whom are carriers of an intermediate-size mutation in FMR1. INTERVENTION(S): Prospective donor ovarian function testing, genetic testing and consultation, and psychological evaluation; institutional assisted reproduction ethics committee consultation, and controlled ovarian hyperstimulation-IVF with cryopreservation of embryos for potential future self-use. MAIN OUTCOME MEASURE(S): Successful cryopreservation of embryos for autologous use by the prospective donor (younger sister) before ovum donation. RESULTS(S): Three blastocysts were frozen. CONCLUSION(S): Requests for sibling ovum donation, while understandable and ethically sanctioned under typical circumstances, prove particularly challenging in some patients with POF given uncertainties regarding the prognosis of the currently asymptomatic sister, risks of genetic transmission of POF, and fiduciary responsibilities to address the reproductive interests of the prospective donor. A multidisciplinary approach was highly beneficial in this case.