Hypotrichosis simplex of the scalp is associated with nonsense mutations in CDSN encoding corneodesmosin.

We have identified nonsense mutations in the gene CDSN (encoding corneodesmosin) in three families suffering from hypotrichosis simplex of the scalp (HSS; OMIM 146520). CDSN, a glycoprotein expressed in the epidermis and inner root sheath (IRS) of hair follicles, is a keratinocyte adhesion molecule. Truncated CDSN aggregates were detected in the superficial dermis and at the periphery of hair follicles. Our findings suggest that CDSN is important in normal scalp hair physiology.

The single cell as a tool for genetic testing: credibility, precision, implication.

PURPOSE: To investigate the influence of amplicons size and cell type on allele dropout and amplification failures in single-cell based molecular diagnosis. METHODS: 730 single lymphocytes and amniotic cells were collected from known heterozygotes individuals to one of the common Ashkenazi Jewish mutations: 1278+TATC and IVS12+1G>C which cause Tay Sachs Disease, IVS20+6T and 854A>C which underlie Familial Dysautonomia and Canavan Disease. DNA was extracted and analyzed by our routine methods. RESULTS: Reduced rates of allele dropout and amplification failure were found when smaller amplification product were designed and in amniotic cultured cells compared to peripheral lymphocytes. Cultured lymphocytes, induced to divide, demonstrated significantly less allele dropout than non induced lymphocytes suggesting the role of division potential on amplification efficiency. CONCLUSION: Single cell based diagnosis should be designed for each mutation. Minimal sized amplicons and cell having division potential should be preferred, as well as sensitive techniques to detect preferential amplification.

Genotyping of patients with sporadic and radiation-associated meningiomas.

Ionizing radiation is the most established risk factor for meningioma formation. Our aim was to evaluate the main effect of selected candidate genes on the development of meningioma and their possible interaction with ionizing radiation in the causation of this tumor. The total study population included 440 cases and controls: 150 meningioma patients who were irradiated for tinea capitis in childhood, 129 individuals who were similarly irradiated but did not develop meningioma, 69 meningioma patients with no previous history of irradiation, and 92 asymptomatic population controls. DNA from peripheral blood samples was genotyped for single nucleotide polymorphisms (SNP) in 12 genes: NF2, XRCC1, XRCC3, XRCC5, ERCC2, Ki-ras, p16, cyclin D1, PTEN, E-cadherin, TGFB1, and TGFBR2. SNP analysis was done using the MassArray system (Sequenom, San Diego, CA) and computerized analysis by SpectroTYPER. Logistic regressions were applied to evaluate main effect of each gene on meningioma formation and interaction between gene and radiation. Intragenic SNPs in the Ki-ras and ERCC2 genes were associated with meningioma risk (odds ratio, 1.76; 95% confidence interval, 1.07-2.92 and odds ratio, 1.68; 95% confidence interval, 1.00-2.84, respectively). A significant interaction was found between radiation and cyclin D1 and p16 SNPs (P for interaction = 0.005 and 0.057, respectively). Our findings suggest that Ki-ras and ERCC2 SNPs are possible markers for meningioma formation, whereas cyclin D1 and p16 SNPs may be markers of genes that have an inverse effect on the risk to develop meningioma in irradiated and nonirradiated populations.

Genetic and biochemical analyses of Israeli osteogenesis imperfecta patients.

Osteogenesis imperfecta (OI) is clinically characterized by abnormal bone fragility, with most patients harboring heterozygote germline mutations in the COL1A1 or COL1A2 genes that encode the chains of type I procollagen, the major protein in bone. More than 250 mutations in both genes in OI patients have been reported, mostly missense mutations affecting glycine residues in the triple helical domains of the two chains. These mutations disrupt protein folding and structure, and their effects often can be detected by the analysis of proteins synthesized but cultured fibroblasts or, less often, osteoblasts. In this study, mutational analysis of all the COL1A1 and part of the COL1A2 was performed using exon-specific PCR amplification followed by denaturing gradient gel electrophoresis (DGGE) analysis and complemented by DNA sequencing in 57 Israeli OI patients from 55 unrelated families. Protein analysis was also performed using cultured fibroblasts obtained from a subset of these OI patients. Of 57 OI patients analyzed, 35 had OI type 1, 12 has OI type III, 8 had OI type IV, and 2 had OI type II. Fourteen different pathogenic mutations (10 novel) were identified in the COL1A1 gene: 3 missense, 5 nonsense, 3 insertion/deletion frameshift, 2 splice junction mutations, and 1 in frame deletion. We conclude that COL1A1 mutations underlie a subset of Israeli OI patients, that most commonly in OI type I, the mutations are contained within the COL1A1 gene, and that there are no predominant mutations in Jewish OI patients. Lastly, the use of protein analyses complements genetic analyses.

Genetic counseling in hereditary breast/ovarian cancer in Israel: psychosocial impact and retention of genetic information.

Genetic counseling for individuals at high risk for developing breast and ovarian cancer (oncogenetic counseling) involves evaluation of cancer risk, psychological assessment, and genetic testing for germline mutations in BRCA1/BRCA2 genes. The long-term psychosocial impact of oncogenetic counseling on consultees and the retention of oncogenetic information are uncertain. We retrospectively interviewed 155 women who underwent oncogenetic counseling in a single medical center in Israel in 1996 (N = 50) and 1998 (N = 105). There were 29 (18.7%) BRCA1/BRCA2 mutation carriers and 126 non-carriers; 58 (37.4%) had a past or present history of cancer, and 97 (62.6%) were first-degree relatives within breast/ovarian cancer families. A questionnaire evaluating self-reported distress and anxiety symptoms before and after counseling, as well as the retention of relevant information (e.g., individual and offspring cancer risk, early detection schemes), one and three years after the initial consultation was administered. Overall, oncogenetic counseling had a minimal effect on anxiety-related symptoms. Mutation carriers reported anxiety-associated symptoms, such as sleeplessness and "bad mood", more frequently than non-carriers following oncogenetic counseling. As expected, 61.8% of carriers and only 30% of non-carriers accurately remembered the personal and offspring cancer risk and preventive and early detection schemes. We conclude that although there seemed to be slight worsening of anxiety-related symptoms following oncogenetic counseling in BRCA1/BRCA2 mutation carriers, these symptoms were minimal and did not affect everyday life activities. In addition, there is an ongoing need to emphasize oncogenetic information to high-risk individuals.

Genomic analyses of primary and metastatic serous epithelial ovarian cancer.

Epithelial ovarian cancer is the most lethal gynecologic malignancy in the western world. In 75% of patients, peritoneal metastases are found at the time of primary surgery. However, the genetic events leading to the development of ovarian tumors and to the genetic progression toward metastasis remain unclear. To gain insight into this issue, the types and patterns of DNA copy number changes were compared between primary ovarian tumors and their respective metastases by using comparative genomic hybridization (CGH) and fluorescence in situ hybridization (FISH). The genetic alterations (deletions and amplifications) detected by CGH were similar in the primary tumors and in their respective metastases. Moreover, the FISH results show a similar pattern of chromosomal abnormalities. Our results imply that the major gross genetic changes in ovarian cancer take place in the primary tumor, and the additional genetic changes that may occur in the metastases are not detectable by CGH.

Comparative genomic hybridization analysis of craniopharyngiomas.

OBJECT: Craniopharyngioma is the most common childhood brain tumor and is thought to arise from embryonic remnants of the Rathke pouch. Some craniopharyngiomas are monoclonal in origin and hence presumably harbor somatic genetic alterations, although the precise molecular mechanisms involved in craniopharyngioma development are unknown. The goal of this study was to identify genetic alterations in craniopharyngiomas. METHODS: To gain insight into the molecular mechanisms involved in development of these tumors, the authors analyzed nine adamantinomatous craniopharyngiomas by using comparative genomic hybridization. Six tumors (67%) displayed at least one genomic alteration, and three had six or more alterations. Only two tumors displayed a decrease in DNA copy number, and in all others an increase in DNA copy number was noted. CONCLUSIONS: The authors conclude that a subset of craniopharyngiomas consists of monoclonal tumors arising from activation of oncogenes located at specific chromosomal loci.

Bloom syndrome and Fanconi's anemia: rate and ethnic origin of mutation carriers in Israel.

BACKGROUND: The Bloom syndrome gene, BLM, was mapped to 15q26.1 and its product was found to encode a RecQ DNA helicase. The Fanconi's anemia complementation group C gene was mapped to chromosome 9q22.3, but its product function is not sufficiently clear. Both are recessive disorders associated with an elevated predisposition to cancer due to genomic instability. A single predominant mutation of each disorder was reported in Ashkenazi Jews: 2281delATCTGAinsTAGATTC for Bloom syndrome (BLM-ASH) and IVS4 + 4AT for Fanconi's anemia complementation group C. OBJECTIVES: To provide additional verification of the mutation rate of BLM and FACC in unselected Ashkenazi and non-Ashkenazi populations analyzed at the Sheba Medical Center, and to trace the origin of each mutation. METHODS: We used polymerase chain reaction to identify mutations of the relevant genomic fragments, restriction analysis and gel electrophoresis. We then applied the Pronto kit to verify the results in 244 samples and there was an excellent match. RESULTS: A heterozygote frequency of 1:111 for BLM-ASH and 1:92 for FACC was detected in more than 4,000 participants, none of whom reported a family history of the disorders. The Pronto kit confirmed all heterozygotes. Neither of the mutations was detected in 950 anonymous non-Ashkenazi Jews. The distribution pattern of parental origin differed significantly between the two carrier groups, as well as between each one and the general population. CONCLUSIONS: These findings as well as the absence of the mutations in non-Ashkenazi Jews suggest that: a) the mutations originated in the Israelite population that was exiled from Palestine by the Roman Empire in 70 AD and settled in Europe (Ashkenazi), in contrast to those who remained; and b) the difference in origin distribution of the BS and FACC mutations can be explained by either a secondary migration of a subgroup with a subsequent genetic drift, or a separate geographic region of introduction for each mutation.

Chromosome aberration and environmental physical activity: Down syndrome and solar and cosmic ray activity, Israel, 1990-2000.

The possibility that environmental effects are associated with chromosome aberrations and various congenital pathologies has been discussed previously. Recent advances in the collection and computerization of data make studying these potential associations more feasible. The aim of this study was to investigate a possible link between the number of Down syndrome (DS) cases detected prenatally or at birth yearly in Israel over a 10-year period compared with the levels of solar and cosmic ray activity 1 year before the detection or birth of each affected child. Information about 1,108,449 births was collected for the years 1990-2000, excluding 1991, when data were unavailable. A total of 1,310 cases of DS were detected prenatally or at birth--138 in the non-Jewish community and 1,172 in the Jewish population. Solar activity indices--sunspot number and solar radio flux 2,800 MHz at 10.7 cm wavelength for 1989-1999--were compared with the number of DS cases detected. Pearson correlation coefficients (r) and their probabilities (P) were established for the percentage of DS cases in the whole population. There was a significant inverse correlation between the indices of solar activity and the number of cases of DS detected--r=-0.78, P=0.008 for sunspot number and r=-0.76, P=0.01 for solar flux. The possibility that cosmophysical factors inversely related to solar activity play a role in the pathogenesis of chromosome aberrations should be considered. We have confirmed a strong trend towards an association between the cosmic ray activity level and the incidence of DS.

Origin and spread of the 1278insTATC mutation causing Tay-Sachs disease in Ashkenazi Jews: genetic drift as a robust and parsimonious hypothesis.

The 1278insTATC is the most prevalent beta-hexosaminidase A ( HEXA) gene mutation causing Tay-Sachs disease (TSD), one of the four lysosomal storage diseases (LSDs) occurring at elevated frequencies among Ashkenazi Jews (AJs). To investigate the genetic history of this mutation in the AJ population, a conserved haplotype (D15S981:175-D15S131:240-D15S1050:284-D15S197:144-D15S188:418) was identified in 1278insTATC chromosomes from 55 unrelated AJ individuals (15 homozygotes and 40 heterozygotes for the TSD mutation), suggesting the occurrence of a common founder. When two methods were used for analysis of linkage disequilibrium (LD) between flanking polymorphic markers and the disease locus and for the study of the decay of LD over time, the estimated age of the insertion was found to be 40+/-12 generations (95% confidence interval: 30-50 generations), so that the most recent common ancestor of the mutation-bearing chromosomes would date to the 8th-9th century. This corresponds with the demographic expansion of AJs in central Europe, following the founding of the Ashkenaz settlement in the early Middle Ages. The results are consistent with the geographic distribution of the main TSD mutation, 1278insTATC being more common in central Europe, and with the coalescent times of mutations causing two other LSDs, Gaucher disease and mucolipidosis type IV. Evidence for the absence of a determinant positive selection (heterozygote advantage) over the mutation is provided by a comparison between the estimated age of 1278insTATC and the probability of the current AJ frequency of the mutant allele as a function of its age, calculated by use of a branching-process model. Therefore, the founder effect in a rapidly expanding population arising from a bottleneck provides a robust parsimonious hypothesis explaining the spread of 1278insTATC-linked TSD in AJ individuals.

Hexosaminidase A deficiency is an uncommon cause of a syndrome mimicking amyotrophic lateral sclerosis.

Patients with adult hexosaminidase A (Hex A) deficiency may have clinical manifestations similar to amyotrophic lateral sclerosis (ALS). Mutations in the hexosaminidase A (HEXA) gene are common in the Jewish Ashkenazi population in Israel. Serum samples of 115 Israeli patients with sporadic ALS were screened for enzymatic activity to detect "enzyme-based carriers." Fifteen samples with low (< 50%) enzymatic activity were subjected to mutation analysis, which included the two common mutations in the HEXA gene among Ashkenazi Jews (+1278TATC and IVS12+1G-->C). Three "enzymatic carrier" patients of Moroccan origin were checked for two additional mutations (DeltaF304/305 and Arg170-->Gln), specific to this ethnic group. Two "enzymatic carrier" patients of Iraqi origin were analyzed for the mutation Gly250-->Val, specific to this population. The mutation Gly 269-->Ser was screened in carriers of Ashkenazi origin only (n = 10). The only abnormalities found were heterozygous +1278TATC mutations in two Ashkenazi patients. Their clinical presentation was not different from that usually encountered in ALS. The frequency of mutations in the HEXA gene among Israeli ALS patients was not higher than in the healthy Israeli population. Therefore, Hex A deficiency seems to be a very unlikely cause of an ALS-mimic syndrome.

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,XX(SRY+), 45,X(SRY+), 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.

Specific mutations in the HEXA gene among Iraqi Jewish Tay-Sachs disease carriers: dating of founder ancestor.

The incidence of Tay-Sachs disease (TSD) carriers, as defined by enzyme assay, is 1:29 among Ashkenazi Jews and 1:110 among Moroccan Jews. An elevated carrier frequency of 1:140 was also observed in the Iraqi Jews (IJ), while in other Israeli populations the world's pan-ethnic frequency of approximately 1:280 has been found. Recently a novel mutation, G749T, has been reported in 38.7% of the IJ carriers (24/62). Here we report a second novel HEXA mutation specific to the IJ TDS carriers: a substitution of cytosine 1351 by guanosine (C1351G), resulting in the change of leucine to valine in position 451. This mutation was found in 33.9% (21/62) of the carriers and in none of 100 non-carrier IJ. In addition to the two specific mutations, 14.5% (9/62) of the IJ carriers bear a known "Jewish" mutation (Ashkenazi or Moroccan) and 11.3% (7/62) carry a known "non-Jewish" mutation. In 1 DNA sample no mutation has yet been detected. To investigate the genetic history of the IJ-specific mutations (C1351G and G749T), the allelic distribution of four polymorphic markers (D15S131, D15S1025, D15S981, D15S1050) was analyzed in IJ heterozygotes and ethnically matched controls. Based on linkage disequilibrium, recombination factor (theta) between the markers and mutated loci, and the population growth correction, we deduced that G749T occurred in a founder ancestor 44.8 +/- 14.2 generations (g) ago [95% confidence interval (CI) 17.0-72.6 g] and C1351G arose 80.4 +/- 35.9 g ago (95% CI 44.5-116.3 g). Thus, the estimated dates for introduction of mutations are: 626 +/- 426 A.D. (200-1052 A.D.) for G749T and 442 +/- 1077 B.C. (1519 B.C. to 635 A.D.) for C1351G.

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.

A missense mutation in the LIM2 gene is associated with autosomal recessive presenile cataract in an inbred Iraqi Jewish family.

In an inbred Iraqi Jewish family, we have studied three siblings with presenile cataract first noticed between the ages of 20 and 51 years and segregating in an autosomal recessive mode. Using microsatellite repeat markers in close proximity to 25 genes and loci previously associated with congenital cataracts in humans and mice, we identified five markers on chromosome 19q that cosegregated with the disease. Sequencing of LIM2, one of two candidate genes in this region, revealed a homozygous T-->G change resulting in a phenylalanine-to-valine substitution at position 105 of the protein. To our knowledge, this constitutes the first report, in humans, of cataract formation associated with a mutation in LIM2. Studies of late-onset single-gene cataracts may provide insight into the pathogenesis of the more common age-related cataracts.

Prenatal diagnosis of Down syndrome: ten year experience in the Israeli population.

Second trimester maternal serum biochemical markers, introduced between 1990 and 1995, were supplemented with new ultrasound methods at 14-16 weeks and first trimester biochemical markers between 1995 and 2000. This study evaluated the effectiveness of a Down syndrome (DS) prevention program among the Israeli Jewish population between 1990 and 2000. We collected data on the total number of prenatal tests performed on Israeli Jewish women, DS cases detected prenatally and DS livebirths in Israel during these years. We also studied the use of the newer screening tests in 1990, 1992, and 2000. Between 1990 and 1995, use of chromosomal studies for DS in this population increased from 11.3% to 21.6% and the percentage of cases detected prenatally from 53% to 70%. However, between 1996 and 2000, even with the new screening methods, the utilization rate remained similar (20.7% and 19.8%, respectively) and the percentage detected prenatally decreased to 61% in 2000. The total cost per case detected increased from $47,971 US dollars in 1990 to $75,229 US dollars in 1992, and to $190,171 US dollars in 2000. Between 1990 and 1995, improvement in the percentage of cases detected prenatally was associated with a significant increase in the amniocentesis rate-both are attributed to the introduction of second trimester maternal serum biochemical marker tests. Unexpectedly, the introduction between 1995 and 2000 of new genetic methods to assess the DS risk did not improve the percentage detected or reduce the amniocentesis rate, and was accompanied by an increased cost per case detected.