Shlomit Rienstein

Familial vs sporadic ovarian tumors: characteristic genomic alterations analyzed by CGH

OBJECTIVE Our purpose was to get an overview of the genetic events leading to the development of familial and sporadic ovarian tumors and to identify chromosomal regions that may contain genes important in tumor progression. METHODS The comparative genomic hybridization (CGH) technique was employed in a total of 46 epithelial ovarian or peritoneal tumors: 27 sporadic tumors, 11 tumors disected from BRCA1 mutation (185delAG) carriers, and eight from BRCA2 mutation (6174delT) carriers (familial tumors). RESULTS The average number of genetic alterations (deletions and amplifications) was significantly (alpha=0.0069) higher in familial tumors (9.17 +/- 4.25 alterations per tumor in the BRCA1 mutation carriers and 7.25 +/- 6.06 in the BRCA2 mutation carriers) compared to the sporadic group (4.26 +/- 3.61 alterations per tumor). The pattern of the chromosome amplifications resembled in the three groups and the most common amplifications detected were at chromosomes 8q, 3q, and 2q. The pattern of the chromosomal deletions varied between the groups. Among the BRCA1 group, the most common deletions were in chromosomes 9 and 19. The BRCA2 group showed a lower frequency of deletions. Deletion of chromosome 16 and 22 were the most frequent ones. No specific chromosomal deletion was significantly indicated in the sporadic group. CONCLUSIONS Familial ovarian tumors exhibit a significantly higher number of chromosomal aberrations and genomic imbalances and nonrandom genetic changes were characterized in the BRCA1 and BRCA2 groups.

Screening of human pluripotent stem cells using CGH and FISH reveals low-grade mosaic aneuploidy and a recurrent amplification of chromosome 1q.

Pluripotency and proliferative capacity of human embryonic stem cells (hESCs) make them a promising source for basic and applied research as well as in therapeutic medicine. The introduction of human induced pluripotent cells (hiPSCs) holds great promise for patient-tailored regenerative medicine therapies. However, for hESCs and hiPSCs to be applied for therapeutic purposes, long-term genomic stability in culture must be maintained. Until recently, G-banding analysis was considered as the default approach for detecting chromosomal abnormalities in stem cells. Our goal in this study was to apply fluorescence in-situ hybridization (FISH) and comparative genomic hybridization (CGH) for the screening of pluripotent stem cells, which will enable us identifying chromosomal abnormalities in stem cells genome with a better resolution. We studied three hESC lines and two hiPSC lines over long-term culture. Aneuploidy rates were evaluated at different passages, using FISH probes (12,13,16,17,18,21,X,Y). Genomic integrity was shown to be maintained at early passages of hESCs and hiPSCs but, at late passages, we observed low rates mosaiciam in hESCs, which implies a direct correlation between number of passages and increased aneuploidy rate. In addition, CGH analysis revealed a recurrent genomic instability, involving the gain of chromosome 1q. This finding was detected in two unrelated cell lines of different origin and implies that gains of chromosome 1q may endow a clonal advantage in culture. These findings, which could only partially be detected by conventional cytogenetic methods, emphasize the importance of using molecular cytogenetic methods for tracking genomic instability in stem cells.

Preimplantation genetic haplotyping a new application for diagnosis of translocation carrier’s embryos- preliminary observations of two robertsonian translocation carrier families

PurposePreimplantation genetic diagnosis using fluorescence in-situ hybridization (PGD-FISH) is currently the most common reproductive solution for translocation carriers. However, this technique usually does not differentiate between embryos carrying the balanced form of the translocation and those carrying the homologous normal chromosomes. We developed a new application of preimplantation genetic haplotyping (PGH) that can identify and distinguish between all forms of the translocation status in cleavage stage embryos prior to implantation.MethodsPolymorphic markers were used to identify and differentiate between the alleles that carry the translocation and those that are the normal homologous chromosomes.ResultsEmbryos from two families of robertsonian translocation carriers were successfully analyzed using polymorphic markers haplotyping.ConclusionsOur preliminary results indicate that the PGH is capable of distinguishing between normal, balanced and unbalanced translocation carrier embryos. This method will improve PGD and will enable translocation carriers to avoid transmission of the translocation and the associated medical complications to offspring.

Proximal 19q trisomy : A new syndrome of morbid obesity and mental retardation

Aims: To report on the clinical and metabolic characteristic and the unique chromosomal defect of a mentally retarded and morbidly obese patient. Methods: A 13-year follow-up, including insulin sensitivity, lipid profile and polysomnography studies and various therapeutic interventions are described. The presence of a supernumerary marker in karyotype preparation was further studied by fluorescence in situ hybridization (FISH). Comparative genomic hybridization (CGH) was used to identify the source of the chromosomal marker. Results: Insulin resistance was found by the homeostatic model assessment (HOMA) and the quantitative insulin sensitivity check index (QUICKI). M-FISH identified euchromatin derived from chromosome 19, and CGH confirmed the FISH results and demonstrated that the supernumerary marker derived from 19q12 to 19q13.2. Conclusion: The clinical and metabolic characteristics in association with partial chromosomal trisomy differ our patient from the currently known syndromes of obesity and mental retardation. The metabolic impairments in this case can derive from unbalanced expression of several genes in the 19q12–19q13.2 region, genes that are related to adipose tissue homeostasis and insulin resistance. The clinical and genetic similarities to a previously reported case may suggest that partial 19q trisomy is a new syndrome of obesity and mental retardation.

True hermaphroditism with ambiguous genitalia due to a complicated mosaic karyotype: clinical features, cytogenetic findings, and literature review.

Abnormal recombination between the X and Y chromosomes during meiosis, occurring outside the pseudoautosomal region, can result in translocation of the SRY gene from the Y to the X chromosome, and consequently in abnormal sexual differentiation, such as the development of 46,XX males or true hermaphroditism. In this report we present clinical, cytogenetic, and molecular‐cytogenetic data of a patient with ambiguous genitalia and true hermaphroditism, who had a unique mosaic karyotype, comprising three different cell lines: 46,XXSRY+, 45,XSRY+, and 45,X. The mosaic karyotype of our patient probably represents two different events: abnormal recombination between the X and Y chromosomes during paternal meiosis, and postzygotic loss of one of the X chromosomes. Replication studies demonstrated that in 80% of the XX cells, the SRY sequence was located on the active X chromosome. This finding suggests nonrandom X inactivation and, together with the presence of the SRY gene, explains the male phenotype of our patient. On the other hand, the presence of the 45,X cell line may have contributed to genital ambiguity. We conclude that fluorescence in situ hybridization (FISH) analysis with SRY probes is highly recommended and allows accurate diagnosis and optimal management in cases of 46,XX hermaphroditism and ambiguous genitalia.

Comparative genomic hybridization analysis of radiation-associated and sporadic meningiomas

Ionizing irradiation to the skull is a known risk factor for meningioma development. To gain insight into the molecular mechanisms that underlie radiation-associated meningioma (RAM), we characterized the somatic genetic alterations in 16 RAMs by using comparative genomic hybridization and compared the pattern of alterations with 17 nonradiation-associated meningiomas (non-RAM). Most tumors (29/33;87.9%) displayed at least one DNA copy number alteration, and 11 out of 33 (33%) exhibited four or more changes. The mean number of DNA copy number changes was similar in RAMs (2.4+/-1.9) and in non-RAMs (2.5+/-1.9). The most common DNA losses were noted in chromosome 22 (56.2% in RAM, and 47% in non-RAM) and chromosome 1 (37.5% in RAM and 35.3% in non-RAM), with no significant differences between the two groups. Noteworthy, gain in DNA copy number of chromosomes 8 and 12 was detected in two RAM tumors only. In conclusion, no significant differences were noted between RAMs and non-RAMs regarding the number of genetic changes and the extent and frequency of chromosomes 1 and 22 losses. These preliminary data suggest that the tumorogenic pathways of meningioma formation are similar, regardless of previous skull irradiation.

Genetic alterations detected by comparative genomic hybridization and recurrence rate in epithelial ovarian carcinoma

To assess the putative correlation between comparative genomic hybridization (CGH)-detectable genetic alterations in epithelial ovarian cancer and disease recurrence, conventional CGH was performed on 45 epithelial ovarian cancers: 26 tumors from sporadic, BRCA mutation noncarriers and 11 and 8 tumors from BRCA1 and BRCA2 mutation carriers, respectively. Relevant clinical data, including histology, grade, stage, size of residual tumor, recurrence, and survival, were obtained from outpatient and inpatient charts. Among the 45 cases, the most common regions involving gain of DNA copy number were 3q (n = 23; 51%), 8q (n = 21; 47%), and 1q (n = 14; 31%), and the most common regions with loss were 19 and 22 at 9 cases (20%) each, followed by 5q (n = 6; 13%). In multivariate analysis, the total number of genetic alterations was not associated with risk of recurrence, but gain in 5p was associated with a higher risk of recurrence (hazard ratio HR = 6.06, P = 0.0399), and gain in 1p as well as loss in 5q were associated with a significant decrease in recurrence (HR = 0.08, P = 0.0079, and HR = 0.10, P = 0.0143, respectively). Recurrence rate in patients with epithelial ovarian cancer is seemingly associated with specific genetic alterations detected by CGH, but the specific genes involved and the implications of these findings await further studies.

Caudal dysplasia sequence with penile enlargement: case report and a potential pathogenic hypothesis.

The clinical spectrum of caudal dysplasia sequence (CDS) is noted for its diversity. The origin of CDS remains unknown, though poorly controlled gestational diabetes has been implicated in some cases. Here we describe the case of a newborn with CDS associated with penile enlargement (PE). The main anomalies included anal atresia, agenesis of the kidneys and of the sacrococcygeal vertebrae, dysgenesis of lumbar vertebrae, and bilateral cryptorchidism. Penile enlargement (7 cm), a rather unusual finding, has so far not been reported in association with CDS. Chromosomal analysis failed, and the neonate died 30 min after birth. Comparative genomic hybridization analysis using stored DNA showed a balanced normal male DNA content, which negates chromosomal losses or gains as a cause of CDS and/or PE. PE due to virilizing-type adrenal hyperplasia, caused by common mutations in the genes encoding for the adrenal enzymes 21-hydroxylase and 11-hydroxylase, was ruled out. We report on a previously unpublished case of the coexistence of PE and severe CDS and propose a possible pathogenetic hypothesis of this association.

Mutations in the sarcosine dehydrogenase gene in patients with sarcosinemia

Sarcosinemia is an autosomal recessive metabolic trait manifested by relatively high concentrations of sarcosine in blood and urine. Sarcosine is a key intermediate in 1-carbon metabolism and under normal circumstances is converted to glycine by the enzyme sarcosine dehydrogenase. We encountered six families from two different descents (French and Arab), each with at least one individual with elevated levels of sarcosine in blood and urine. Using the “candidate gene approach” we sequenced the gene encoding sarcosine dehydrogenase (SARDH), which plays an important role in the conversion of sarcosine to glycine, and found four different mutations (P287L, V71F, R723X, R514X) in three patients. In an additional patient, we found a uniparental disomy in the region of SARDH gene. In two other patients, we did not find any mutations in this gene. We have shown for the first time that mutations in the SARDH gene are associated with sarcosinemia. In addition, our results indicate that other genes are most probably involved in the pathogenesis of this condition.

Post-childhood Presentation and Diagnosis of DiGeorge Syndrome:

Background and Objectives. The diversity of clinical presentations makes the diagnosis of DiGeorge syndrome (DGS) a diagnostic challenge. The objective of our study was to report the clinical presentation of DGS in the post-childhood period. Methods. A retrospective study, investigating patients diagnosed clinically and genetically with DGS at Sheba Medical Center during the period of 2010-2013. Post-childhood period was defined as age >10 years. Results. During the study period, 29 patients were diagnosed with DGS. Nine (31%) patients with DGS were diagnosed in their post-childhood period. The basis for clinical suspicion was diverse. However, once the suspicion was brought to attention, additional symptoms consistent with DGS were noted at up to 88% of patients who presented characteristic of facial features and developmental delay. Conclusion. Our research shows that diagnosing DGS patients in the post-childhood period is not uncommon. Characteristic facial features and developmental delay, although not leading presenting symptoms, are found very frequently in patients with DGS.