Spectrum of genes for inherited hearing loss in the Israeli Jewish population, including the novel human deafness gene ATOH1.

Mutations in more than 150 genes are responsible for inherited hearing loss, with thousands of different, severe causal alleles that vary among populations. The Israeli Jewish population includes communities of diverse geographic origins, revealing a wide range of deafness-associated variants and enabling clinical characterization of the associated phenotypes. Our goal was to identify the genetic causes of inherited hearing loss in this population, and to determine relationships among genotype, phenotype, and ethnicity. Genomic DNA samples from informative relatives of 88 multiplex families, all of self-identified Jewish ancestry, with either non-syndromic or syndromic hearing loss, were sequenced for known and candidate deafness genes using the HEar-Seq gene panel. The genetic causes of hearing loss were identified for 60% of the families. One gene was encountered for the first time in human hearing loss: ATOH1 (Atonal), a basic helix-loop-helix transcription factor responsible for autosomal dominant progressive hearing loss in a five-generation family. Our results show that genomic sequencing with a gene panel dedicated to hearing loss is effective for genetic diagnoses in a diverse population. Comprehensive sequencing enables well-informed genetic counseling and clinical management by medical geneticists, otolaryngologists, audiologists, and speech therapists and can be integrated into newborn screening for deafness.

Genotype-phenotype correlation in the presentation of retinoblastoma among 149 patients.

In this work, we describe the association between a germline RB1 mutation and disease presentation characteristics of retinoblastoma. The study evaluates a retrospective cohort of 164 of the 295 patients with retinoblastoma who were treated at a single center between 1988 and 2013 and who were referred for genetic evaluation. Peripheral blood was evaluated for RB1 mutations via Multiplex Ligation-dependent Probe Amplification (MLPA), sequencing, and detection of recurrent CpG transition mutations. Patients with an RB1 mutation were compared to patients without a mutation, regarding epidemiological factors and clinical presentation. Genetic analysis was completed for 149 patients. An RB1 mutation was identified in 76 children (51.0%) including 90.0% of the bilateral patients, and 19.8% of the unilateral unifocal patients (24.7% if we include the unilateral multifocal cases). The most common mutations were a stop codon (38.2%), a splicing error (19.7%) and a large deletion (15.8%). The mutation type correlated only with sex (Likelihood ratio, p = 0.0240) and with macular involvement (Likelihood ratio, p = 0.0591 and Fisher's exact one tail test p = 0.0459 for more macular involvement if there are germline mutations). It did not correlate with laterality, with the reason for referral, or with diagnosis age. However, identification of a mutation was more common in babies diagnosed under one year of age (Likelihood ratio, p < 0.0001). In conclusion, we were surprised that our genetic tests have also found mutations in 24.7% of patients with unilateral retinoblastoma in addition to most of the bilateral children. These unilateral patients with a germline mutation have an increased risk for other cancers throughout their lives, and their first-degree relatives have an increased risk for retinoblastoma. Therefore, genetic testing for RB1 mutation should be offered to all patients, including the unilateral cases.

An Ashkenazi founder mutation in the PKHD1 gene.

Autosomal recessive polycystic kidney disease (ARPKD) is usually detected late in pregnancies in embryos with large echogenic kidneys accompanied by oligohydramnios. Hundreds of private pathogenic variants have been identified in the large PKHD1 gene in various populations. Yet, because of the large size of the gene, segregation analysis of microsatellite polymorphic markers residing in the PKDH1 locus has commonly been utilized for prenatal diagnosis. Keeping in mind the limitations of this strategy, we utilized it for testing 7 families with affected fetuses or newborns, of which in 5 at least one parent was Ashkenazi, and identified that the same haplotype was shared by the majority of the Ashkenazi parents (7/9). This led us to suspect that they carry the same founder mutation. Whole Exome analysis of DNA from a fetus of one of the families detected an already known pathogenic variant c.3761_3762delCCinsG, an indel variant resulting in frameshift (p.Ala1254GlyfsX49). This variant was detected in 9 parents (5 families), of them 7 individuals were Ashkenazi and one Moroccan Jew who shared the same haplotype, and one Ashkenazi, who carried the same variant on a recombinant haplotype. Screening for this variant in 364 Ashkenazi individuals detected 2 carriers. These findings suggest that although c.3761_3762delCCinsG is considered one of the frequent variants detected in unrelated individuals, and was thought to have occurred independently on various haplotypes, it is in fact a founder mutation in the Ashkenazi population.

Patients' Attitudes Towards Disclosure of Genetic Test Results to Family Members: The Impact of Patients' Sociodemographic Background and Counseling Experience.

Many factors predict the intention to disclose genetic information to relatives. The article examines the impact of patients' socio-demographic factors on their intention to disclose genetic testing results to their relatives. Data were collected in eight genetic clinics in Israel. Patients were requested to fill in a questionnaire after counseling. A convenience sample of 564 participants who visited these clinics was collected for a response rate of 85 %. Of them, 282 participants came for susceptibility testing for hereditary cancers (cancer group), and 282 for genetic screening tests (prenatal group). In the cancer group, being secular and having more years of education correlated positively with the intention to disclose test results to relatives. In the prenatal group, being married and female correlated positively with the intention to disclose. In the cancer group, being religious and with less years of education correlated positively with the view that the clinician should deliver the results to the family. In the prenatal group, being male and unmarried correlated positively with this belief. In both groups, being of young age correlated with the perception that genetic information is private. Varied sociodemographic factors affect the intention to inform family members. Thus, knowing the social background of patients will shed light on people's attitudes to genetic information and will help clinicians provide effective counseling in discussions with patients about the implications of test results for relatives.

Whole Exome Sequencing Reveals Mutations in Known Retinal Disease Genes in 33 out of 68 Israeli Families with Inherited Retinopathies.

Whole exome sequencing (WES) is a powerful technique for identifying sequence changes in the human genome. The goal of this study was to delineate the genetic defects in patients with inherited retinal diseases (IRDs) using WES. WES was performed on 90 patient DNA samples from 68 families and 226 known genes for IRDs were analyzed. Sanger sequencing was used to validate potential pathogenic variants that were also subjected to segregation analysis in families. Thirty-three causative mutations (19 novel and 14 known) in 25 genes were identified in 33 of the 68 families. The vast majority of mutations (30 out of 33) have not been reported in the Israeli and the Palestinian populations. Nine out of the 33 mutations were detected in additional families from the same ethnic population, suggesting a founder effect. In two families, identified phenotypes were different from the previously reported clinical findings associated with the causative gene. This is the largest genetic analysis of IRDs in the Israeli and Palestinian populations to date. We also demonstrate that WES is a powerful tool for rapid analysis of known disease genes in large patient cohorts.

Genetic screening in patients with Retinoblastoma in Israel.

Retinoblastoma (Rb) is a childhood tumor (~1 in 20,000 live births) developing in the retina due to mutations in the RB1 gene. Identification of the oncogenic mutations in the RB1 gene is important for the clinical management and for genetic counseling to families with a child or a parent affected with the tumor. Here we present our experience in detecting the pathogenic mutations in blood samples, from 150 unrelated Rb patients and highlight the relevant counseling issues. Mutation screening in the RB1 gene was based on Sanger sequencing, mosaicism of recurrent CpG transition mutations was detected by allele specific PCR and multiplex ligation dependent probe amplification for detecting of large deletions/duplications. The overall detection rate of mutations in our cohort was 55% (82/150). In the familial cases it was 100% (17/17), in bilateral and unilateral-multifocal sporadic cases 91% (50/55), and in the unilateral sporadic cases 19% (15/78). Nonsense mutations and small deletions or insertions that results in transcripts with premature termination codons that are subject to nonsense mediated decay were the most frequent, detected in 50/82 (61%) of the patients. The rest were large deletions detected in 14/82 (17%), splice site mutations detected in 11/82 (13%), missense mutations in four patients and mutations in the promoter sequence in three patients. Mutation mosaicism ranging from 10 to 30% was detected by allele specific PCR in ten patients, 9% (5/55) of patients with bilateral tumor and 33% (5/15) of the patients with unilateral tumor. In three patients rare variants were detected as the only finding which was also detected in other healthy family members. Allele specific amplification of recurrent mutations raises in our cohort the identification rate from 82 to 91% in the sporadic bilateral cases and from 13 to 19% in the unilateral sporadic cases. Most mosaic cases could not be identified by Sanger sequencing and therefore screening for recurrent CpG transition mutations by allele specific amplification is of utmost importance. Molecular screening is important for the genetic counseling regarding the risk for tumor development and the relevance for prenatal diagnosis but in several families is accompanied by detecting rare variants that might be rare polymorphisms or low penetrant mutations.

'The BRCA clock is ticking!': negotiating medical concerns and reproductive goals in preimplantation genetic diagnosis.

Despite research on BRCA1/2 mutation carriers attitudes towards preimplantation genetic diagnosis (PGD), considerably less is known about individuals' experience with its use. Through case reports of BRCA1/2 mutation carriers' thoughts on, and use of, PGD, this paper highlights how the option of PGD is experienced and negotiated in the context of reproductive and life-course goals. Drawing on qualitative interviews with 38 BRCA1/2 mutation carriers, this article focuses on a subsample of 10 interviewees who sought consultation for, and/or attempted, PGD, with in-depth reports of 3 cases and summary decisions of the remaining 7. Three couples decided against PGD, and one was deciding at the time of the interview. Interviewees discuss key aspects of their experience prior to, and going through, PGD for BRCA1/2, including potential challenges of becoming pregnant through PGD and of heightened pressure to achieve their reproductive goals more quickly. Despite considerable focus on ethical issues in screening embryos for mutations associated with adult-onset cancer risk, less attention has been paid to the technical, logistical, and related psychosocial issues. Narrative case reports may help individuals develop appropriate expectations of PGD for BRCA prepare for possibly challenging decisions and outcomes, and ultimately determine whether it is compatible with their reproductive goals.

Identification of mutations causing inherited retinal degenerations in the israeli and palestinian populations using homozygosity mapping.

PURPOSE: The Israeli and Palestinian populations are known to have a relatively high level of consanguineous marriages, leading to a relatively high frequency of autosomal recessive (AR) diseases. Our purpose was to use the homozygosity mapping approach, aiming to prioritize the set of genes and identify the molecular genetic causes underlying AR retinal degenerations in the Israeli and Palestinian populations. METHODS: Clinical analysis included family history, ocular examination, full-field electroretinography (ERG), and funduscopy. Molecular analysis included homozygosity mapping and mutation analysis of candidate genes. RESULTS: We recruited for the study families with AR nonsyndromic retinal degenerations, including mainly retinitis pigmentosa (RP), cone-rod degeneration (CRD), and Leber congenital amaurosis (LCA). With the aim to identify the causative genes in these families, we performed homozygosity mapping using whole genome single nucleotide polymorphism (SNP) arrays in 125 families. The analysis revealed the identification of 14 mutations, 5 of which are novel, in 16 of the families. The mutations were identified in the following eight genes: RDH12, PROM1, MFRP, TULP1, LCA5, CEP290, NR2E3, and EYS. While most patients had a retinal disease that is compatible with the causing gene, in some cases new clinical features are evident. CONCLUSIONS: Homozygosity mapping is a powerful tool to identify genetic defects underlying heterogeneous AR disorders, such as RP and LCA, in consanguineous and nonconsanguineous patients. The identification of significant and large homozygous regions, which do not include any known retinal disease genes, may be a useful tool to identify novel disease-causing genes, using next generation sequencing.

Lynch Syndrome in high risk Ashkenazi Jews in Israel.

Lynch Syndrome is caused by mutations in DNA mismatch repair genes. Diagnosis is not always trivial and may be costly. Information regarding incidence, genotype-phenotype correlation, spectrum of mutations and genes involved in specific populations facilitate the diagnostic process and contribute to clinical work-up. To report gene distribution, mutations detected and co-occurrence of related syndromes in a cohort of Ashkenazi Jews in Israel. Patients were identified in dedicated high risk clinics in 3 medical centers in Israel. Diagnostic process followed a multi-step scheme. It included testing for founder mutations, tumor testing, gene sequencing and MLPA. Lynch Syndrome was defined either by positive mutation testing, or by clinical criteria and positive tumor analysis. We report a cohort of 75 Ashkenazi families suspected of Lynch Syndrome. Mutations were identified in 51/75 (68%) families: 38 in MSH2, 9 in MSH6, and 4 in MLH1. 37/51 (73%) of these families carried one of the 3 'Ashkenazi' founder mutations in MSH2 or MSH6. Each of the other 14 families carried a private mutation. 3 (6%) were large deletions. Only 20/51 (39%) families were Amsterdam Criteria positive; 42 (82%) were positive for the Bethesda guidelines and 9 (18%) did not fulfill any Lynch Syndrome criteria. We report C-MMRD and co-occurrence of BRCA and Lynch Syndrome in our cohort. Mutation spectra and gene distribution among Ashkenazi Jews are unique. Three founder Lynch Syndrome mutations are found in 73% families with known mutations. Among the three, MSH2 and MSH6 are the most common. These features affect the phenotype, the diagnostic process, risk estimation, and genetic counseling.

Genetic predisposition to radiation induced sarcoma: possible role for BRCA and p53 mutations.

The estimated incidence of radiation-associated sarcoma (RAS) is 0.03-0.2 % in 5 years post treatment. Most cancer predisposing genes are involved in DNA repair; therefore, elevated RAS risk in these patients is plausible. Cases of angiosarcoma post breast cancer treatment were reported in BRCA1 and BRCA2 carriers. We report the genetic evaluation of seven cases with suspected RAS from patients counseled in our cancer-genetic clinic. Of 2,885 breast cancer patient, 470 were BRCA1 or two mutation carriers and three were p53 mutation carriers. Of them seven developed sarcoma in the field of irradiation; five in the chest wall and two in other sites. Genetic evaluation revealed BRCA1 mutation in two, BRCA2 mutation in additional patient and a carrier of p53 mutation. The estimation of risk for RAS in patients with genetic predisposition is limited due to the rarity of this event, and the bias in referral to the clinic toward younger age. With these limitations the rate of RAS is 0.43 % (2/470, 95 % CI -0.17 to 1.02, SE = 0.3) in this group in a median follow-up of 8.2 years (range 1 month to 51 years). If we assume irradiation for the breast in 80 % of the patients than rate of RAS in group is proximately 0.53 % (2/376, 95 % CI -0.21 to 1.26, SE = 0.37). A BRCA1 carrier which had sarcoma after irradiation to head and neck carcinoma was not included in these analyses. In conclusion, we found a high frequency of BRCA1/2 mutation among our patients diagnosed with RAS. However, we estimated approximately twofold increase in the risk of RAS in BRCA1/2 carriers which was not significant compared to reports in general population. Therefore, RAS is a rare event in BRCA carriers as in the general population, and should not be considered in the decision regarding irradiation treatment in this population.

Genetic counseling services and training of genetic counselors in Israel: an overview.

Genetic counseling services have existed in Israel since 1964 and are available in almost all the major hospitals. Given the socialized healthcare system and small country size, genetic services are generally accessible and often free. The existence of founder mutations in various communities in Israel makes genetic testing easier to perform. Yet, the ethnic, cultural and religious diversity of the population has major implications on the design of the screening programs and the use of genetic services. The Israeli Association of Genetic Counselors (IAGC) was established in 2008 and had existed informally since 1989. There are two Master level genetic counseling training programs (6 students/class, 2 year program): Hebrew University-Hadassah Medical School (established in 1997) and the Technion (established in 2009). Genetic counselors' clinical training is largely observational and 2 years of supervised counseling sessions post degree are required for board exam eligibility. Genetic counselors are licensed and lead counseling sessions individually, but currently must work under medical geneticist supervision. This is the first article to summarize the history and training of Master level genetic counselors in Israel. Genetic services, coverage and regulations are also described.

Incorporating information regarding preimplantation genetic diagnosis into discussions concerning testing and risk management for BRCA1/2 mutations: a qualitative study of patient preferences.

BACKGROUND: Studies have shown that BRCA1/2 mutation carriers are interested in learning about reproductive options such as preimplantation genetic diagnosis (PGD) to prevent passing their risk onto their children. However, attitudes vary widely, and the procedure raises complex ethical and psychosocial issues. This complexity, plus the highly technical nature of PGD, makes it difficult to integrate PGD information into genetic counseling sessions that already cover probabilistic, emotionally charged risk information. METHODS: A total of 33 carriers of the BRCA1/2 mutation who were of reproductive age and had previously undergone genetic counseling viewed a tutorial regarding PGD and were interviewed concerning their attitudes toward PGD and preferences about how to include PGD information in genetic counseling. RESULTS: The majority of participants preferred to be briefly informed of the availability of PGD information, and to receive written materials regarding PGD, but with the option of deferring detailed discussion if they already believed themselves to be overloaded or perceived that PGD was not immediately relevant to their risk management and/or childbearing plans. For some individuals, the stress of testing temporarily interfered with information processing, producing states of cognitive avoidance ("in a fog," or "tuning out"). Some preferred to discuss PGD with a physician with whom they had an ongoing relationship (eg, obstetrician/gynecologist, primary care provider, or oncologist). CONCLUSIONS: Providers offering cancer genetic testing may consider indicating the availability of PGD information to their patients, while attending to the patients' level of interest and ability to absorb information. Research is needed to link patient responses to information overload with psychosocial outcomes (eg, distress, and quality of decision-making). Continuing medical education is needed to support providers in facilitating informed decisions regarding PGD.

"My funky genetics": BRCA1/2 mutation carriers' understanding of genetic inheritance and reproductive merger in the context of new reprogenetic technologies.

Deleterious mutations in the BRCA1/BRCA2 genes elevate lifetime risk of breast and ovarian cancer. Each child of a mutation-positive parent has a 50% chance of inheriting it. Preimplantation genetic diagnosis (PGD) permits prospective parents to avoid the birth of a BRCA-mutation-positive child, introducing predictability into a process historically defined by chance. This investigation explored how BRCA1/2 mutation carriers understand genetic inheritance and consider a child's inheritance of a BRCA1/2 mutation, given the opportunities that exist to pursue PGD. Thirty-nine female and male BRCA1/2 mutation carriers of reproductive age were recruited from urban cancer and reproductive medical centers. Participants completed a standardized educational presentation on PGD and prenatal diagnosis, with pre- and posttest assessments. An interdisciplinary team of qualitative researchers analyzed data using grounded theory techniques. Participants expressed the belief that reproduction yields children with unique genetic strengths and challenges, including the BRCA1/2 mutation, family traits for which predictive tests do not exist, and hypothetical genetic risks. Participants expressed preference for biologically related children, yet stated their genetically "well" partner's lineage would be marred through reproductive merger, requiring the well partner to assume the burden of the BRCA1/2 mutation via their children. Participants expressed diverse views of genetically "well" partners' participation in family planning and risk management decisions. Pressure to use reprogenetic technology may grow as genetic susceptibility testing becomes more widely available. Work with individuals and couples across the disease spectrum must be attuned to the ways beliefs about genetic inheritance play into reproductive decision-making.

Genome-wide SNP genotyping identifies the Stereocilin (STRC) gene as a major contributor to pediatric bilateral sensorineural hearing impairment.

Hearing loss is the most prevalent sensory perception deficit in humans, affecting 1/500 newborns, can be syndromic or nonsyndromic and is genetically heterogeneous. Nearly 80% of inherited nonsyndromic bilateral sensorineural hearing loss (NBSNHI) is autosomal recessive. Although many causal genes have been identified, most are minor contributors, except for GJB2, which accounts for nearly 50% of all recessive cases of severe to profound congenital NBSNHI in some populations. More than 60% of children with a NBSNHI do not have an identifiable genetic cause. To identify genetic contributors, we genotyped 659 GJB2 mutation negative pediatric probands with NBSNHI and assayed for copy number variants (CNVs). After identifying 8 mild-moderate NBSNHI probands with a Chr15q15.3 deletion encompassing the Stereocilin (STRC) gene amongst this cohort, sequencing of STRC was undertaken in these probands as well as 50 probands and 14 siblings with mild-moderate NBSNHI and 40 probands with moderately severe-profound NBSNHI who were GJB2 mutation negative. The existence of a STRC pseudogene that is 99.6% homologous to the STRC coding region has made the sequencing interpretation complicated. We identified 7/50 probands in the mild-moderate cohort to have biallelic alterations in STRC, not including the 8 previously identified deletions. We also identified 2/40 probands to have biallelic alterations in the moderately severe-profound NBSNHI cohort, notably no large deletions in combination with another variant were found in this cohort. The data suggest that STRC may be a common contributor to NBSNHI among GJB2 mutation negative probands, especially in those with mild to moderate hearing impairment.

Complete remission, in BRCA2 mutation carrier with metastatic pancreatic adenocarcinoma, treated with cisplatin based therapy.

Carriers of a germline mutation in the BRCA genes, in particular BRCA2, have an increased risk of developing pancreatic adenocarcinoma when compared with the general population. While the addition of cisplatin to gemcitabine did not produce survival benefit compared to single-agent gemcitabine in prospective trials it is postulated that the addition of DNA cross-linking agent such as cisplatin to standard gemcitabine chemotherapy should be considered in known BRCA mutation carriers. We report a case of pancreatic adenocarcinoma arising in a 60-year-old carrier of a rare BRCA2 (1153insertionT) germline mutation. The patient received gemcitabine without any response and actually progression of the disease had occurred. Therefore cisplatin was added in combination with gemcitabine. A dramatic complete response to therapy was encountered with no evidence of disease in both CT scans and markers (CA19-9). In conclusion, in patients with known BRCA mutation associated pancreatic adenocarcinoma, the addition of a DNA cross-linking agent such as cisplatin should be considered. Physicians should consider BRCA mutation testing when the diagnosis of pancreatic cancer is established, especially when the patient belongs to an ethnic group where founder mutations exist, and/or there is strong personal or family history of cancer. This may be applied also to other metastatic tumors diagnosed in BRCA1/2 carriers.

Two BRCA1/2 founder mutations in Jews of Sephardic origin.

Founder mutations in BRCA1/2 genes have been detected in several Jewish communities in Israel, including in Ashkenazi Jews and Jews who immigrated to Israel from Iraq, Yemen, Iran and Afghanistan. We analyzed DNA samples of patients of Sephardic origin (descendents of Jews from the Iberian Peninsula) with breast cancer (BC) and/or ovarian cancer (OC) and additional family history of these cancers. In this study we identified 2 mutations: p.A1708E in BRCA1 and c.67 + 1G > A (IVS2 + 1G > A) in BRCA2, each in 3 unrelated patients. The frequency of the two mutations was 26-31% among Sephardic high risk families and about 3% among the full cohort of 177 patients of this origin who were tested in our center. Based on haplotype analysis we concluded that these mutations are most probably founder mutations in Sephardic Jews. We recommend testing the two mutations in women of Sephardic origin who apply for BRCA testing because of personal and/or family history of BC and/or OC. Furthermore, we suggest adding them to the 5 mutations included in "The Jewish panel" of BRCA1/2 mutations that are being tested in Israel.

Clinical and genetic heterogeneity of congenital adrenal hypoplasia due to NR0B1 gene mutations.

INTRODUCTION: X-linked adrenal hypoplasia congenita (AHC) is a rare disorder caused by mutations or complete deletion of the NR0B1 gene that encodes the DAX-1 protein, an orphan member of the nuclear receptor superfamily. AHC is characterized by adrenal insufficiency in infancy and early childhood. Later, hypogonadotropic hypogonadism (HH) manifests as pubertal failure. PATIENTS AND METHODS: We evaluated the clinical, endocrine and molecular characteristics of 12 AHC patients from 5 families diagnosed between 1984 and 2007 in Israel. RESULTS: Most of the boys (10/12) presented with signs of adrenal insufficiency such as salt wasting and failure to thrive during the neonatal period. Aldosterone deficiency usually preceded cortisol deficiency requiring early mineralocorticoid therapy. Serum cortisol levels in the first weeks of life varied from very low to high levels (<2.76 to >1776 nmol/l). Five boys showed signs of precocious sexual development during infancy and childhood, including enlargement of the penis and testes. In four patients the initial diagnoses were erroneous. Molecular analysis of the NR0B1 gene identified point mutations in six patients including a novel splice site mutation in one patient and his family (IVS1-1G-->C). Contiguous gene deletion was found in six patients from two families who manifested impaired mental development. CONCLUSIONS: In X-linked AHC caused by different molecular defects in NR0B1 gene, the clinical spectrum of the disease is quite variable and precocious sexual development is a prominent feature. Genetic testing is indicated in boys presenting with salt-wasting with or without cortisol deficiency if congenital adrenal hyperplasia has been ruled out.

Presentation format affects comprehension and risk assessment: the case of prenatal screening.

We studied the effects of presentation formats (frequency, 1-in-N, and visual) and numeracy level on students' understanding of prenatal screening results, as well as their risk assessment for having a fetus with Down syndrome. Frequency format (vs. 1-in-N and visual formats) improved participants' ability to accurately assess the chances of having a fetus with Down syndrome, and was associated with lower risk estimates. High numeracy levels were associated with a better ability to judge risk likelihood. For individuals of low numeracy levels, however, the frequency format significantly facilitated accurate understanding of probability information. This suggests that presenting information in frequency format is particularly beneficial for certain populations.

Mutation spectrum in HNPCC in the Israeli population.

Hereditary non-polyposis colon cancer is caused by mutations in DNA mismatch repair genes. The mutation spectrum in the Israeli population is poorly documented except for the c.1906G>C Ashkenazi founder mutation in the hMSH2 gene. To report our experience in HNPCC screening, the mutations detected and the clinical features among a cohort of Israeli patients. Diagnostic work-up was done in a multi-step process guided by clinical and ethnic information. Tumors of suspected patients were tested for microsatellite instability and immunohistochemistry. Based on tumor analyses, we proceeded to mutation screening by DHPLC followed by sequence analysis and multiplex ligase dependent probe amplification. Ashkenazi Jews were first tested for the c.1906G>C founder mutation. Of the 240 families, 24, including Arabs and Jews from different ethnic origins, were tested positive. All tumors that lost expression of mismatch repair proteins also showed microsatellite instability. There was evidence for involvement of hMSH2 (15) hMLH1 (6) and hMSH6 (3) genes. Mutations were identified in 17/24 (71%) patients: 6 Ashkenazi families harbored the c.1906G>C mutation. Eleven other mutations (2 nonsense, 3 splice site and 6 small deletions) were detected. Three of the mutations are novel. No gross deletions or insertions were detected. This is the first report that characterizes the profile of HNPCC in a cohort of patients in Israel. Tumor testing indicated that the 3 main MMR genes are involved, and that mutation spectrum is broad.