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T Gelbart

Publications and source records attributed to T Gelbart.

At least 55 records · Page 3Linked to original sources
PubMed1993

Identification of six new Gaucher disease mutations.

The four most common mutations account for 97% of the Gaucher disease-producing alleles in Jewish patients and 75% of the alleles in non-Jewish patients. Although at least 15 other mutations and some examples of gene conversion and/or fusion genes have been described, a number of mutations remain unidentified. We have now identified six new mutations, a deletion of a C at the 72 position of the cDNA, a 481C-->T mutation (122Pro-->Ser), a 751T-->C (212Tyr-->His), a 1549G-->A (478Gly-->Ser), a 1604G-->A (496Arg-->His), and a 55-bp deletion. All but one of these were found in single families. The 1604A mutation, however, was observed in four unrelated individuals.

Adolescent↗
PubMed1993

Gaucher disease mutations in non-Jewish patients.

The DNA from 64 non-Jewish patients with Gaucher disease was examined for 29 different glucocerebrosidase mutations that are known to cause the disease. The most common was mutation 1448C and the second most common 1226G. Twenty of the mutations remained unidentified. These results were compared to those obtained from 122 Jewish patients, in whom the most common mutations were 1226G and 84GG. Among the non-Jewish patients 15.6% of the mutations remained unidentified, while among the Jewish patients only 1.2% remained unidentified, and even screening for the five most common mutations identified all but 2.9% of the Jewish mutations. The greater diversity of mutations among the non-Jewish patients has important implications with respect to DNA-based screening, diagnosis and counselling.

Adolescent↗
PubMed1993

Gaucher disease: gene frequencies in the Ashkenazi Jewish population.

DNA from over 2,000 Ashkenazi Jewish subjects has been examined for the four most common Jewish Gaucher disease mutations, which collectively account for about 96% of the disease-producing alleles in Jewish patients. This population survey has made possible the estimation of gene frequencies for these alleles. Eighty-seven of 1,528 individuals were heterozygous for the 1226G (N370S) mutation, and four presumably well persons were homozygous for this mutation. The gene frequency for the 1226G allele was calculated to be .0311, and when these data were pooled with those obtained previously from another 593 Jewish subjects, a gene frequency of .032 with a standard error of .004 was found. Among 2,305 normal subjects, 10 were found to be heterozygous for the 84GG allele, giving a gene frequency of .00217 with a standard error of .00096. No examples of the IVS2(+1) mutation were found among 1,256 samples screened, and no 1448C (L444P) mutations were found among 1,528 samples examined. Examination of the distribution of Gaucher disease gene frequencies in the general population shows that the ratio of 1226G mutations to 84GG mutations is higher than that in the patient population. This is presumed to be due to the fact that homozygotes for the 1226G mutation often have late-onset disease or no significant clinical manifestations at all. To bring the gene frequency in the patient population into conformity with the gene frequency in the general population, nearly two-thirds of persons with a Gaucher disease genotype would be missing from the patient population, presumably because their clinical manifestations were very mild.

Base Sequence↗
PubMed1992

A less costly regimen of alglucerase to treat Gaucher's disease.

BACKGROUND: Alglucerase (Ceredase) provides effective enzyme-replacement treatment for patients with Gaucher's disease, but at the usually recommended dose of 60 U per kilogram of body weight every two weeks (130 U per kilogram per month), it costs $382,200 per year for a 70-kg patient. Theoretical considerations suggest that more frequent administration would be more efficient. METHODS: Fourteen patients with type 1 Gaucher's disease that was moderately severe to severe were given 30 U of alglucerase per kilogram per month, in divided doses given either daily or three times weekly, or 120 U given three times weekly. The effect of the treatment on the size of the liver and spleen and on blood counts was compared with published data on patients who received a total dose four to five times as large as the lower dose we used and who received treatment every two weeks. RESULTS: The response to 30 U of alglucerase per kilogram per month, fractionated into three or seven doses weekly, was approximately the same as that reported after the administration every two weeks of a dose four or five times as large, given in the large infusions usually recommended. A fourfold increase in the dose given three times weekly, from 2.3 to 9.2 U per kilogram, did not substantially increase the rate of improvement. CONCLUSIONS: The treatment of Gaucher's disease with smaller total doses of alglucerase given more frequently yields satisfactory results. A dose of 2.3 U per kilogram three times weekly yields major financial benefits with no sacrifice of therapeutic effect. Even taking into account the increased ancillary costs of more frequent administration, this method of administering alglucerase reduces the annual cost of the drug for a 70-kg patient to about $100,000.

Administration, Oral↗
PubMed1992

Mutations in Jewish patients with Gaucher disease.

DNA from 100 unrelated patients, 97 of whom were Jewish and three half-Jewish, was analyzed for 22 mutations known to cause Gaucher disease. All but seven of the alleles were identified as having previously described mutations. Five of the unidentified mutations proved to be a previously undescribed nucleotide substitution in a splice junction (IVS2+1) that causes skipping of exon 2. Thus, only 2 of 197 alleles remained unidentified. Homozygotes for the most common mutation, that a nucleotide (nt) 1226, manifested, on average, the mildest disease and the latest age of onset. The mutation at nt 84 and the newly described IVS2+1 mutation, which do not produce any enzyme, were associated with earlier onset and more severe disease. Five of the mutations were considered to be "public," in the sense that they were found in more than one unrelated individual. Screening for these five mutations permitted detection of 97.5% of all Gaucher alleles in this patient population. Because the mutation at nt 1226 is underrepresented in the patient population and because not all homozygotes come to medical attention, screening the Ashkenazi population using DNA analysis should detect approximately 99% of all heterozygotes.

Alleles↗
PubMed1992

Polymorphisms in the human glucocerebrosidase gene.

The two glucocerebrosidase genes from a patient with Gaucher disease were cloned and 8850 bp of each sequenced. Each clone had a single nucleotide change accounting for the clinical glucocerebrosidase deficiency, an A to G transition at cDNA nucleotide 1226 in one clone, and an insertion of a G at cDNA nucleotide 84 in the other clone. Sequence analysis revealed that there were 11 additional differences between the two clones. The clone with the nt 1226 mutation was, as is always the case, Pv1.1- (polymorphic PvuII site present). The 84GG clone was Pv1.1+. Examination of 35 normal subjects and 51 Gaucher disease patients was consistent with the existence of only two major haplotypes. Two additional minor haplotypes were found, one in Africans and one in the white population. These represented additional mutations superimposed on the basic two haplotypes. Two unrelated patients with Gaucher disease seemed to be exceptions in the 5' end of the gene was heterozygous for the + and - haplotypes but the most 3' marker was homozygous. These patients are believed to have a gene deletion on one allele. In addition to these studies, we correct 28 minor errors in the originally published sequence.

Alleles↗
PubMed1992

Gaucher disease. Clinical, laboratory, radiologic, and genetic features of 53 patients.

We have reviewed our experiences with the clinical, laboratory, radiologic, and genetic features of 53 patients with Gaucher disease. Most were evaluated during early adult life, with a mean age of 33 years. Our patients were evaluated in a referral center, and therefore the data need to be interpreted with caution when applied to the general patient population, which includes a greater proportion of very mild cases. Thirty-nine patients were Ashkenazi Jews, 13 were non-Jewish and 1 was half-Jewish. The most common presenting symptom was bleeding related to splenomegaly and thrombocytopenia. The chronic symptoms, evaluated an average of 20 years after the diagnosis had been established, were mainly skeletal. Splenectomy had been performed in 43% of our patients and there was no evidence that this procedure accelerated the progression of liver and bone involvement. DNA from the patients was examined for 20 different mutations. The association between the 1226G/1226G genotype and a milder clinical course, and between the 1226G/84GG and 1226/1448C genotypes with more severe clinical manifestations, was confirmed. Repeated follow-up examinations in 29 patients revealed that in the majority of the patients, progression of the disease occurs during childhood, adolescence, or early adulthood with a marked tendency for stabilization thereafter. This observation suggests that Gaucher disease in most of the patients is not a relentless progressive disorder but a rather stable disorder during adulthood. The indications for the newly introduced intravenous enzyme replacement therapy as well as of future experimental treatments should be examined in the light of the natural history of the disease.

Adolescent↗
PubMed1991

Identification of the second common Jewish Gaucher disease mutation makes possible population-based screening for the heterozygous state.

Gaucher disease is an autosomal recessive glycolipid storage disease characterized by a deficiency of glucocerebrosidase. The disease is most common in persons of Ashkenazi Jewish ancestry and the most common mutation, accounting for about 75% of the mutant alleles in this population, is known to be an A----G substitution at cDNA nucleotide (nt) 1226. Screening for this disease has not been possible because nearly 25% of the mutant alleles had not been identified, but linkage analysis led to the suggestion that most of these could be accounted for by a single mutation. We now report the discovery of this mutation. The insertion of a single nucleotide, a second guanine at cDNA nt 84 (the 84GG mutation), has been detected in the 5' coding region of the glucocerebrosidase gene. The amount of mRNA produced is shown to be normal but since the frameshift produced early termination, no translation product is seen. This finding is consistent with the virtual absence of antigen found in patients carrying this mutation. The 84GG mutation accounts for most of the previously unidentified Gaucher disease mutations in Jewish patients. The common Jewish mutation at nt 1226, the 84GG mutation, and the less-common mutation at nt 1448 accounted for 95% of all of the Gaucher disease-producing alleles in 71 Jewish patients. This now makes it possible to screen for heterozygotes on a DNA level with a relatively low risk of missing couples at risk for producing infants with Gaucher disease.

Age Factors↗
PubMed1991

DNA sequence abnormalities of human glucose-6-phosphate dehydrogenase variants.

Over 400 supposedly biochemically and genetically distinct variants of glucose-6-phosphate dehydrogenase (G6PD) have been described in the past. In order to investigate these variants at the DNA sequence level we have now determined the relevant sequences of introns of G6PD and describe a method which allows us to rapidly determine the sequence of the entire coding region of G6PD. This technique was applied to six variants that cause G6PD deficiency to be functionally so severe as to result in nonspherocytic hemolytic anemia. Although the patients were all unrelated, G6PD Marion, Gastonia, and Minnesota each had identical mutations, a G----T at nucleotide (nt) 637 in exon 6 leading to a Val----Leu substitution at amino acid 213. The mutations of Nashville and Anaheim were identical to each other, viz. G----A at nt 1178 in exon 10 producing a Arg----His substitution at amino acid 393. G6PD Loma Linda had a C----A substitution at nt 1089 in exon 10, producing a Asn----Lys change at amino acid 363. The results confirm our earlier results suggesting that the NADP-binding site is in a small region of exon 10 and suggest the possibility that this area is also concerned with the binding of glucose-6-P.

Anemia, Hemolytic, Congenital Nonspherocytic↗
PubMed1991

High frequency of the Gaucher disease mutation at nucleotide 1226 among Ashkenazi Jews.

Reliable estimates of the frequency of Gaucher disease-producing mutations are not available. The high frequency of Gaucher disease in the Ashkenazi Jewish population is due to the occurrence of a mutation at nucleotide (nt) 1226. We have screened 593 DNA samples from normal Ashkenazi Jews, as well as 62 DNA samples from all our Ashkenazi Jewish patients with Gaucher disease, for the presence of the 1226 mutation. In the 593 presumed normal Ashkenazi Jewish individuals the 1226 mutation was identified in the heterozygous state in 37 and in the homozygous state in two, giving a gene frequency of .035 for the mutation. This 1226 mutation represented 73% of the 124 Gaucher disease alleles in Jewish Gaucher disease patients. Accordingly we estimate that the gene frequency for Gaucher disease among the Ashkenazi Jewish population is .047, which is equivalent to a carrier frequency of 8.9% and a birth incidence of 1:450.

Adolescent↗
PubMed1990

The facile detection of the nt 1226 mutation of glucocerebrosidase by 'mismatched' PCR.

The most common Gaucher disease-producing mutation among Ashkenazi Jews is an A----G substitution at cDNA nt 1226 (genomic nt 5841). We describe a simple method for detecting this mutation both in genomic DNA and in cDNA by performing polymerase chain reaction (PCR) using a 5'-primer mismatched at one nucleotide so as to create an Xho I restriction site. When the mutation is present. the 105 bp fragment formed is cleaved to 89 and 16 nt fragments. The 89 bp fragment is easily visualized on a gel making it possible to distinguish individuals who do not have the mutation from heterozygotes and homozygotes.

Base Sequence↗
PubMed1990

Gamma-glutamylcysteine synthetase deficiency and hemolytic anemia.

gamma-Glutamylcysteine synthetase is one of the enzymes of glutathione (GSH) synthesis. A deficiency of this enzyme has been found only once previously in humans: it was associated with spinocerebellar degeneration and hemolytic anemia. We report the case of a woman, daughter of fifth cousins, who was gamma-glutamylcysteine-synthetase-deficient. Modest decreases in the amount of GSH in cultured lymphoblasts and fibroblasts could be documented. The amount of residual enzyme was insufficient to permit detailed studies of the characteristics of the mutant enzymes, but no major abnormality in its Km for cysteine and glutamic acid or in its heat stability were found. In contrast to the earlier report, the only manifestation of the enzyme deficiency was hemolytic anemia. This leads us to conclude that either the occurrence of neurologic symptoms in the other reported family was a chance association or that the clinical expression of this rare defect is pleomorphic.

Adult↗
PubMed1990

Gaucher disease associated with a unique KpnI restriction site: identification of the amino-acid substitution.

In an earlier survey of the glucocerebrosidase locus using 20 restriction enzymes and a 1039 bp probe we found that 1 of 9 Gaucher disease patients had a unique pattern with KpnI. a pattern that was not observed in any other Gaucher patient or in 31 controls. We have now localized the mutation in this patient to a T----A transversion in nucleotide 764 of the cDNA occurring on one of the two glucocerebrosidase alleles. The presumed abnormality in the other allele has not been identified. The deduced amino-acid change in the allele with the mutation at nucleotide 764 is a relatively drastic alteration of amino acid 255 from phenylalanine to tyrosine. The genomic DNAs of 31 other Gaucher disease patients (representing 62 Gaucher disease alleles) were examined for this mutation using the polymerase chain reaction. None were found to have this abnormality.

Base Sequence↗
PubMed1990

Linkage of the PvuII polymorphism with the common Jewish mutation for Gaucher disease.

We have localized the PvuII polymorphism of the glucocerebrosidase gene complex to intron 6 of the active gene. Using the polymerase chain reaction (PCR) to amplify intron 6 of DNA samples from Pv1.1-/Pv1.1+ individuals, we defined the mutation causing this polymorphism as a G----A single-base substitution at position 3931 of the active gene. By analyzing 54 unrelated Gaucher patients we show strong linkage disequilibrium between the Pv1.1- genotype and the common Jewish mutation 1226 causing the adult type of this disease. Gaucher disease patients heterozygous for the 1226 allele and one unidentified allele (1226/?), particularly those of Jewish ancestry, were predominantly of the Pv1.1-/PV1.1+ genotype. This suggests that one of the unknown alleles may be relatively common and linked to the Pv1.1+ genotype.

Cell Line↗
PubMed1989

The human glucocerebrosidase gene and pseudogene: structure and evolution.

We report the sequence of the entire human gene encoding beta-glucocerebrosidase and that of the associated pseudogene. The gene contains 11 exons extending from base pair 355 to base pair 7232 in the overall sequence. The gene promoter contains TATA- and CAT-like boxes upstream of the major 5' end of the glucocerebrosidase RNA. The two TATA boxes lie between nucleotides (-23)-(-27) and (-33)-(-39) and the two possible CAT boxes reside between nucleotides (-90)-(-94) and (-96)-(-99) in relation to the major 5' end of the mRNA. The functionality of the promoter region was monitored by coupling it to the bacterial gene coding for chloramphenicol acetyltransferase (CAT) and assaying the expression of the enzyme in cells transfected with this vector. The glucocerebrosidase promoter not only directs synthesis of the bacterial enzyme but also exhibits the same pattern of tissue-specific expression as that of the endogenous gene. An apparently tightly linked pseudogene is approximately 96% homologous to the functional gene. However, introns 2, 4, 6, and 7 have large "deletions" consisting of Alu sequences 313, 626, 320, and 277 bp in length, respectively. It is entirely possible that the ancestral gene lacks these sequences and that they have been inserted into the introns of the functioning gene. There is also a 55-bp deletion from a part of exon 9 flanked by a short inverted repeat. The sequence data should facilitate development of methods for diagnosis of Gaucher disease at the molecular level.

Base Sequence↗