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Biomedical subjects

M Shohat

Publications and source records attributed to M Shohat.

At least 73 records · Page 4Linked to original sources
PubMed1998

The impact of consanguinity worldwide.

Consanguineous marriages have been practiced for hundreds of years in many parts of the world. The rate of congenital malformations among the offspring is 2.5 times higher than that among the offspring of unrelated parents, mainly due to the expression of autosomal-recessive disorders, and hospitalization for these reasons causes a major financial burden. An increase in sterility and in the rates of abortion, stillbirths, perinatal losses and neonatal deaths has been reported by some authors but not by others. It is generally accepted that the advantages of consanguinity outweigh the disadvantages; however, strategies for reducing the burden require a unique approach as discussed in this article.

Journal Article↗
PubMed1997

Further delineation of cerebro-osteo-nephrosis syndrome.

We describe an Israeli Jewish child of Yemenite origin who may be affected with "cerebro-osteo-nephrosis." She is short of stature (height below 3rd centile) due to skeletal abnormalities. She has minor anomalies and borderline intelligence. There is marked proteinuria and she is in kidney failure. Opitz et al. [1985: Am J Med Genet 22:521-529] described 2 Hutterite sisters in America who were suffering from a condition which greatly resembles that of our patient. We question whether these conditions in the two families are the same syndrome with pleiotropic expression, as suggested by Opitz et al., or whether they represent two distinct genetic entities.

Abnormalities, Multiple↗
PubMed1997

[Consanguinity among Arabs in Israel].

In a previous nationwide study, we examined the rate of consanguineous matings in the Israeli Arab community. The average inbreeding coefficient was 0.0192, much higher than that reported for the general population of Israel, 0.0038 in 1956-7. The inbreeding coefficients of 69 Arab villages, towns and cities (excluding the Bedouin in the South) were determined. Knowledge of the inbreeding coefficients of the various local populations is of value for geneticists, pediatricians and gynecologists and for planning suitable health programs.

Arabs↗
PubMed1997

A high-resolution genetic map of the familial Mediterranean fever candidate region allows identification of haplotype-sharing among ethnic groups.

Familial Mediterranean fever (FMF) is a recessive disorder of inflammation caused by mutations in a gene (designated MEFV) on chromosome 16p13.3. We have recently constructed a 1-Mb cosmid contig that includes the FMF critical region. Here we show genotype data for 12 markers from our physical map, including 5 newly identified microsatellites, in FMF families. Intrafamilial recombinations placed MEFV in the approximately 285 kb between D16S468/D16S3070 and D16S3376. We observed significant linkage disequilibrium in the North African Jewish population, and historical recombinants in the founder haplotype placed MEFV between D16S3082 and D16S3373 (approximately 200 kb). In smaller panels of Iraqi Jewish, Arab, and Armenian families, there were significant allelic associations only for D16S3370 and D16S2617 among the Armenians. A sizable minority of Iraqi Jewish and Armenian carrier chromosomes appeared to be derived from the North African Jewish ancestral haplotype. We observed a unique FMF haplotype common to Iraqi Jews, Arabs, and Armenians and two other haplotypes restricted to either the Iraqi Jewish or the Armenian population. These data support the view that a few major mutations account for a large percentage of the cases of FMF and suggest that some of these mutations arose before the affected Middle Eastern populations diverged from one another.

Alleles↗
PubMed1997

Correlation between the incidence of myotonic dystrophy in different groups in Israel and the number of CTG trinucleotide repeats in the myotonin gene.

Myotonic dystrophy (DM) is associated with an increased number of CTG repeats in the 3' untranslated region of the myotonin gene. Because DM has been observed less frequently in Ashkenazic Jews and non-Jews than in North African and Yemenite Jews in Israel, a study of the CTG repeat polymorphism was undertaken in these four groups. Alleles from 126 unrelated healthy North African Jews, 103 Yemenite Jews, 103 Ashkenazic Jews, and 106 Israeli Moslem Arabs were studied by PCR analysis of the trinucleotide repeat in the DM gene, and the size distribution of the CTG repeat was determined. The alleles ranged in length from 5-28 repeats in the Yemenite Jews, 5-26 in Muslim Arabs and North African Jews, and 5-23 in the Ashkenazic Jews. North African and Yemenite Jews were found to have significantly more large repeats in the normal range than Ashkenazic Jews and Muslim Arabs (for over 18 repeats: 9.1% and 13%, respectively, compared to 2.4% and 3.3%, respectively; P < 0.0001). It is suggested that the more frequent occurrence of large CTG repeats in the normal range may represent a greater predisposition to DM.

Africa, Northern↗
PubMed1997

Consanguinity and common adult diseases in Israeli Arab communities.

Consanguinity has a deleterious effect with regard to congenital malformation and rare autosomal recessive diseases; however, little information exists on its role in multifactorial common adult morbidity. We investigated the effects of consanguinity on the prevalence of common diseases in adulthood, including diabetes mellitus, myocardial infarction, bronchial asthma, and duodenal ulcer. As part of a larger study investigating the inbreeding coefficient in the Israeli-Arab community, we distributed questionnaires to parents of 4,100 second-grade students in 158 randomly chosen schools. Among the 3,772 responders (92%), 34.8% of the students' fathers and 31% of their mothers were found to be born to consanguineous matings. There was no difference in the prevalence (males, females) between the offspring of consanguineous versus non-consanguineous matings for diabetes mellitus (consanguinity: 4.3%, 1.5% vs. non-consanguinity: 2.9%, 1.6%) myocardial infarction (2.7%, 0.03% vs. 2.3%, 0.03%), bronchial asthma (2.4%, 2.0% vs. 3.7%, 2.3%), or duodenal ulcer (7.0%, 3.0% vs. 7.8%, 2.9%), respectively. The study suggests that even in a population with a high rate of consanguinity, there is no significant increase in the prevalence of these common adult diseases.

Adult↗
PubMed1997

Construction of a 1-Mb restriction-mapped cosmid contig containing the candidate region for the familial Mediterranean fever locus (MEFV) on chromosome 16p 13.3.

In this paper we describe the assembly and restriction map of a 1.05-Mb cosmid contig spanning the candidate region for familial Mediterranean fever (FMF), a recessively inherited disorder of inflammation localized to 16p13.3. Using a combination of cosmid walking and screening for P1, PAC, BAC, and YAC clones, we have generated a contig of genomic clones spanning approximately 1050 kb that contains the FMF critical region. The map consists of 179 cosmid, 15 P1, 10 PAC, 3 BAC, and 17 YAC clones, anchored by 27 STS markers. Eight additional STSs have been developed from the approximately 700 kb immediately centromeric to this genomic region. Five of the 35 STSs are microsatellites that have not been previously reported. NotI and EcoRI mapping of the overlapping cosmids, hybridization of restriction fragments from cosmids to one another, and STS analyses have been used to validate the assembly of the contig. Our contig totally subsumes the 250-kb interval recently reported, by founder haplotype analysis, to contain the FMF gene. Thus, our high-resolution clone map provides an ideal resource for transcriptional mapping toward the eventual identification of this disease gene.

Base Sequence↗
PubMed1997

Agenesis of the corpus callosum in a mother and son.

Most reported familial cases of agenesis of the corpus callosum have followed either an autosomal recessive or an X-linked recessive pattern of inheritance. To the best of our knowledge, there is only one previous report of a family showing clear-cut autosomal dominant inheritance. We present the second such family, among whom a mother and her son had moderately severe coordination problems and low-normal intelligence. We suggest that agenesis of the corpus callosum, when transmitted as an autosomal dominant trait, is clinically characterized by a relatively milder phenotype than that occurring when inheritance is either autosomal or X-linked recessive and may be more common than has been thought.

Adult↗
PubMed1997

Multiple de novo MPZ (P0) point mutations in a sporadic Dejerine-Sottas case.

Dejerine-Sottas syndrome (DSS), a severe demyelinating peripheral neuropathy with onset in infancy, has been associated with mutations in either PMP22 or MPZ. Most cases of DSS are caused by a single heterozygous dominant point mutation. We identified three de novo point mutations in MPZ exon 3 in a sporadic DSS patient. These three point mutations occur on the same allele and result in three novel amino acid substitutions: Ile(85)Thr, Asn(87)His, and Asp(99)Asn. Our data raise the question as to the potential mechanism(s) involved in the formation of multiple point mutations at a given locus.

Amino Acid Sequence↗
PubMed1997

Interleukin 1beta in serum of women with preterm uterine contractions.

Preterm delivery is a major obstetric and public health problem, accounting for 50-70% of all perinatal deaths. An enzyme-linked immunoassay (ELISA) test was used to determine serum interleukin 1b (IL-1b) levels in 32 women with preterm contractions compared with 26 women in term labour and 11 normal preterm pregnant women. Women with preterm contractions (with or without treatment) had significantly lower mean serum levels of IL-1b (23.5 pgr/ml) compared with women in term labour (218 +/- 57 pgr/ml), but similar levels to pregnant women not in labour at the same weeks of gestation.

Journal Article↗
PubMed1997

A gene for arthrogryposis multiplex congenita neuropathic type is linked to D5S394 on chromosome 5qter.

Arthrogryposis multiplex congenita (AMC) is a heterogeneous-symptom complex characterized by joint contractures at birth that involve more than one part of the body. We performed a genetic-linkage study of one large Israeli-Arab inbred kindred showing autosomal recessive inheritance of AMC neuropathic type that had been recently investigated by our group. After analysis of approximately 80% of the genome, D5S1456, which showed no increased homozygosity, showed increased genotype sharing in affected individuals. Linkage analysis in all family members revealed linkage between AMC and D5S1456 on chromosome 5qter (maximum LOD score 5.3 at recombination fraction .001). Analysis of additional markers in this region places the gene causing AMC in this family between D5S1456 and D5S498.

Arabs↗
PubMed1997

Connexin26 mutations associated with the most common form of non-syndromic neurosensory autosomal recessive deafness (DFNB1) in Mediterraneans.

Non-syndromic neurosensory autosomal recessive deafness (NSRD) is the most common form of genetic hearing loss. Previous studies defined at least 15 human NSRD loci. Recently we demonstrated that DFNB1, located on the long arm of chromosome 13, accounts for approximately 80% of cases in the Mediterranean area. Further analysis with additional markers now identifies several recombinants which narrow the candidate region to approximately 5 cM, encompassed by markers D13S141 and D13S232 and including several ESTs and candidate genes, including the connexin26 (GJB2) gene. Analysis of PCR products from our affected patients' DNA shows two frameshift mutations in the connexin26 gene. Deletion of a G within a stretch of six Gs at position 35 of the GJB2 cDNA (mutation 35delG) leads to premature chain termination and is present in 63% of NSRD chromosomes, demonstrating linkage to chromosome 13. Deletion of a T at position 167 of GJB2 (mutation 167delT), also resulting in premature chain termination, was detected in another patient. Four neutral sequence polymorphisms were also identified. These findings are in agreement with a recent study showing that mutations in the connexin26 gene are associated with genetic forms of deafness in three Pakistani families and that GJB2 is DFNB1. Connexin26 is a member of a large family of proteins involved in formation of gap junctions, which are involved in electrical synapses and the direct transfer of small molecules and ionic currents between neighboring cells. The identification of GJB2 as the DFNB1 gene should provide a better understanding of the biology of normal and abnormal hearing, help form the basis for diagnosis and may facilitate development of strategies for treatment of this common genetic disorder.

Connexin 26↗
PubMed1997

Effects of consanguineous marriage on reproductive outcome in an Arab community in Israel.

Intrafamilial marriage is favoured by the Arab community in Israel, almost all of whom live in villages populated by a few (< 20) founding families. A previous study in Taibe, a large Arab village located 30 km from Tel Aviv, showed a significantly high malformation rate among infants of consanguineous parents. The present study examines the reproductive consequences of parental consanguinity in 610 families from the same village, selected retrospectively through infants routinely seen in the local well baby clinic. All mothers were interviewed with regard to previous pregnancy outcomes, including abortions, stillbirths, and neonatal or infant deaths, as well as the degree of consanguinity. In addition, we analysed the anthropometric measurements of the probands. The incidence of infant deaths was significantly higher in the inbred group (p < 0.001). No significant increase in fetal loss between the inbred and outbred groups was observed. There were no differences in anthropometric features, except for a lower birth weight in the consanguineous group (p < 0.035). This study, combined with our previous studies of the same population, indicates a prominent public health problem associated with consanguineous marriage in the Arab community and a need for specific genetic counselling.

Arabs↗
PubMed1997

Founder BRCA1 and BRCA2 mutations in Ashkenazi Jews in Israel: frequency and differential penetrance in ovarian cancer and in breast-ovarian cancer families.

Germ-line BRCA1 and BRCA2 mutations account for most of familial breast-ovarian cancer. In Ashkenazi Jews, there is a high population frequency (approximately 2%) of three founder mutations: BRCA1 185delAG, BRCA1 5382insC, and BRCA2 6174delT. This study examined the frequency of these mutations in a series of Ashkenazi women with ovarian cancer unselected for family history, compared with the frequency of these mutations in families ascertained on the basis of family history of at least two affected women. Penetrance was compared, both according to the method of family ascertainment (i.e., on the basis of an unselected ovarian cancer proband vs. on the basis of family history) and for the BRCA1 founder mutations compared with the BRCA2 6174delT mutation. There was a high frequency (10/22; [45%]) of germ-line mutations in Ashkenazi women with ovarian cancer, even in those with minimal or no family history (7/18 [39%]). In high-risk Ashkenazi families, a founder mutation was found in 59% (25/42). Families with any case of ovarian cancer were significantly more likely to segregate a founder mutation than were families with site-specific breast cancer. Penetrance was higher in families ascertained on the basis of family history than in families ascertained on the basis of an unselected proband, but this difference was not significant. Penetrance of BRCA1 185delAG and BRCA1 5382insC was significantly higher than penetrance of BRCA2 6174delT (hazard ratio 2.1 [95% CI 1.2-3.8]; two-tailed P = .01). Thus, the high rate of germ-line BRCA1/BRCA2 mutations in Ashkenazi women and families with ovarian cancer is coupled with penetrance that is lower than previously estimated. This has been shown specifically for the BRCA2 6174delT mutation, but, because of ascertainment bias, it also may be true for BRCA1 mutations.

Adult↗
PubMed1997

The lower incidence of myotonic dystrophy in Ashkenazic Jews compared to North African Jews is associated with a significantly lower number of CTG trinucleotide repeats.

Myotonic dystrophy (DM) is associated with an increased number of CTG repeats in the 3' untranslated region of the myotonin gene. Because DM has been observed more frequently in North African Jews than in Ashkenazic Jews in Israel, a study of the CTG repeat polymorphism was undertaken in these 2 groups. Alleles from 70 unrelated North African subjects and 70 unrelated Ashkenazic subjects were studied by PCR analysis of the trinucleotide repeat in the DM gene to determine the ethnic distribution of the number of CTG repeats. The alleles ranged in length from 5 to 26 repeats in the North Africans and 5 to 23 in the Ashkenazim. As has been seen in other populations, none of the chromosomes had a 9-repeat length. North African Jews were found to have significantly more repeats in the normal range than Ashkenazim (for over 14 repeats: 34/140 compared to 7/140; p < 0.0001). It is suggested that this more frequent occurrence of a large number of CTG repeats in the normal range may represent a greater predisposition to DM.

Africa, Northern↗