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Biomedical subjects

E Beutler

Publications and source records attributed to E Beutler.

At least 127 records · Page 7Linked to original sources

Prenatal molecular diagnosis of Gaucher disease.

Prenatal diagnosis of Gaucher disease, the most prevalent glycolipid storage disease, is based on a reliable enzyme assay of cells from amniocentesis or chorionic villous samples. However, this method cannot differentiate among the various forms of the disease. This report details four cases of prenatal diagnosis of Gaucher disease, three of which predate the use of molecular diagnosis. DNA mutation analysis to determine the genotype was predictive of the phenotypic status of the fetus and conformed to the genotype of an affected proband where available.

Adult↗

Five new Gaucher disease mutations.

DNA from 17 individuals with 20 unidentified alleles was subjected to single-stranded conformation polymorphism analysis and/or sequencing and 5 previously undescribed mutations have been identified: 245T, 259T, 635G, 914C del, and IVS10(+2). Two of these mutations, 914C del and IVS10(+2), are null, or "lethal" mutations. Because the other mutation each of these two patients carried was "mild", the phenotype was type I disease. In addition to the new mutations we describe, the second example of the rare 1448G mutation has been documented in one of the patients. This mutation is particularly interesting because in samples studied by restriction analysis with NciI it can readily be confused with the common 1448C mutation. Reexamination of 28 patients who had previously been diagnosed as carrying the 1448C mutation were confirmed to be 1448C.

Adult↗

Study of the molecular defects in pyruvate kinase deficient patients affected by nonspherocytic hemolytic anemia.

We have examined DNA from fifteen unrelated pyruvate kinase deficient patients with hereditary nonspherocytic hemolytic anemia (HNSHA) for the molecular alterations responsible for the enzyme deficiency. All but 3 of the 30 putative mutations were identified. Fourteen different mutations were found. Nine were missense mutations: 320 T-->C, 823 G-->C, 1276 C-->T, 1378 G-->A, 1484 C-->T, 1529 G-->A, 1654 G-->A, 1675 C-->G; three were nonsense mutations: 603 G-->A, 721 G-->T, 1501 C-->T; one was an insertion at 1574 GGG-->GGGG and the other a three nucleotide in-frame deletion 391-392-393 ATC. Eight of these mutations have not been previously described. We also investigated all of the patients for the C/A polymorphism at nt 1705 and the microsatellite ATT repeat in intron 11. All of the mutations that had previously been reported by us (391-393del, 721T, 1484T, 1529A) were found in the context of the same haplotype as the earlier cases, supporting the concept that each may have a single origin.

Anemia, Hemolytic, Congenital Nonspherocytic↗

Three new exon 10 glucose-6-phosphate dehydrogenase mutations.

Three previously undescribed mutations of the glucose-6-phosphate dehydrogenase (G6PD) gene have been documented in patients with hereditary non-spherocytic hemolytic anemia (HNSHA). In none of the cases have we been able to obtain a sufficient volume of blood to characterize the residual enzyme biochemically. "G6PD Calvo Mackenna" was due to an A-->G transition in cDNA nucleotide 1138 creating an Aat II site and resulting in a substitution of valine for isoleucine at amino acid 380. "G6PD Riley" was due to a T-->C transition at cDNA nucleotide 1139 also changing the 380 isoleucine, in this case to a threonine. "G6PD Wisconsin" was due to an C-->G transversion in cDNA nucleotide 1177, destroying a Aci I site and resulting in a substitution of glycine for arginine at amino acid 393. All of these mutations were in exon 10, where mutations that cause HNSHA appear to be clustered. We present a list of the 83 mutations of G6PD that have been documented to the end of April, 1995.

Anemia, Hemolytic, Congenital Nonspherocytic↗

The clinical course of treated and untreated Gaucher disease. A study of 45 patients.

One hundred nineteen patients with Gaucher disease were examined in the past 13 years. Of these 45 were examined 3 or more times over a time-span exceeding one year and all such patients are included in this study. Adult patients showed little progression of disease. There were few alterations in the blood counts, no increase in size of liver and spleen, and changes in skeletal lesions were largely confined to pre-existing lesions. Some children appeared to have more progressive disease, but since many of the children in this study were treated with alglucerase, it is difficult to draw conclusions about the natural progression of the disease at earlier ages. Treatment with alglucerase resulted in gradual normalization of blood counts, decrease in the size of liver and spleen, and parallel decreases in the serum angiotensin converting enzyme and chitotriosidase levels. Skeletal symptoms were decreased in all patients, and skeletal lesions showed modest improvement in patients treated for two years or more. The response of patients to low dose/high frequency (2.3 U/Kg 3 x weekly; 30 U/Kg/Mo) therapy was indistinguishable from the response observed and previously reported by others with much larger doses. Changing the dosage from 30 U/Kg/Mo to 120 U/Kg/Mo was not attended by any significant changes in response. Criteria for the selection of patients for treatment with alglucerase are proposed. We suggest that a starting dose of 15 to 30 U/Kg/month, fractionated 3 times weekly be used for all patients, regardless of severity or site of involvement, and that upward dosage adjustments be made only in such rare patients who may not respond adequately to this dose in 6 to 12 months.

Adolescent↗

Molecular abnormality of a phosphoglycerate kinase variant (PGK-Alabama).

The molecular abnormality of a phosphoglycerate kinase variant associated with severe red cell enzyme deficiency ( about 4% of normal) and episodes of hemolysis with jaundice was examined. The Michaelis constants for the substrates and co-enzymes (1.3-diphosphoglycerate, 3-phosphoglycerate, ATP and ADP) were not grossly different from that of normal. However that variant enzyme was very labile in vitro. Nucleotide sequence analysis of the variant cDNA revealed a deletion of codon AAG in exon 7. The codon deletion should result in the election of one of the tandem lysine residues existing at amino acid 190-191 of the enzyme protein. Based on the three dimensional structure of the protein, molecular instability could could be induced by the deletion of a lysine residue.

Adult↗

A strategy for cloning the hereditary hemochromatosis gene.

Selective hybridization of small intestine and liver cDNA libraries was carried out using yeast artificial chromosomes (YACs) surrounding D6S105, the microsatellite that appears to be close to the gene for hereditary hemochromatosis (HFE). Of 14 candidate probes hybridizing with these YACs, only one, designated. LD5-1, detected abnormalities in southern blots of patients with hemochromatosis. Two different abnormalities. were detected in 3 of 55 patients with hemochromatosis with the LD5-1 probe, and one of these was detected in one of 44 normal subjects. The gene that hybridizes with this probe is located about 300-400 kb centromeric of D6S105. It is transcribed into mRNA that is about 8.5 kb in length in many tissues, including peripheral blood leukocytes. The available sequence indicates tha it codes for a zinc finger protein. We propose that there is a reasonable probability that LD5-1 hybridizes with the gene for hereditary hemochromatosis.

Base Sequence↗

Gaucher disease.

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Adult↗

Molecular study of pyruvate kinase deficient patients with hereditary nonspherocytic hemolytic anemia.

DNA analysis was performed on 30 unrelated patients with hereditary nonspherocytic hemolytic anemia (HNSHA) who had been found to be pyruvate kinase (PK) deficient by enzyme assay. 19 different mutations were identified among 58 of the 60 alleles at risk. 13 of these were missense mutations that caused single amino acid changes. Included were the following nucleotide substitutions: 401A, 464C, 993A, 1022C, 1076A, 1178G, 1179A, 1373A, 1378A, 1456T, 1484T, 1493A, 1529A. The remaining six mutations were as follows: two nonsense mutations, 721T and 808T; a nucleotide deletion, 307C; a nucleotide insertion, 1089GG; a three nucleotide in frame deletion, 391-392-393 and a deletion of 1149 bp from the PKLR gene that resulted in the loss of exon 11. All the patients were studied for two polymorphic sites, nucleotide (nt) 1705 A/C and a microsatellite in intron 11, to better understand the origin of the mutations. The 1529A mutation, which is the most common mutation in the European population, was found in 25 alleles. With a single exception this mutation was in linkage disequilibrium with both of the polymorphic markers, i.e., found with 1705C and 14 repeats in the microsatellite. This finding is consistent with a single origin of this common mutation. Other mutations occurring more than once were of much lower frequency than the 1529A mutation.

Anemia, Hemolytic, Congenital Nonspherocytic↗

2-Chlorodeoxyadenosine activity in patients with untreated chronic lymphocytic leukemia.

PURPOSE: 2-chlorodeoxyadenosine (2-CdA; cladribine) is a purine analog with activity in patients with chronic lymphocytic leukemia (CLL) who fail to respond to alkylator therapy. We conducted a phase II trial of 2-CdA in previously untreated CLL patients. PATIENTS AND METHODS: 2-CdA was administered to 20 patients with previously untreated CLL as a 0.1-mg/kg/d 7-day continuous intravenous infusion every 28 to 35 days until maximum response or prohibitive toxicity. RESULTS: A median of four courses (range, one to nine) was administered to each patient. Five patients (25%) achieved a complete response and 12 (60%) achieved a partial response, for an overall response rate of 85%. The median response follow-up duration was 8+ months (range, 3 to 27). Myelosuppression was the principal toxicity. Four of 20 patients (20%) experienced grade III or IV thrombocytopenia. Three patients, all of whom received corticosteroid therapy, developed opportunistic infections at a median of 19 months following discontinuation of 2-CdA therapy. CONCLUSION: 2-CdA has major activity in patients with previously untreated CLL, and the lower response rates seen in previously treated patients may be due in part to poor marrow reserve from prior therapy. Determination of the relative effectiveness of 2-CdA, fludarabine, and chlorambucil in the treatment of CLL patients will require a randomized trial.

Adult↗

A novel intrachromosomal rearrangement in the beta-globin gene found in an African-American family.

We describe here a deletion of 34 nucleotides from the 3' end of the first intervening sequence of the beta-globin gene covering the AGGC splice junction, and the insertion of 32 nucleotides of the delta-globin gene at the same location. This gene rearrangement was detected in three members of an African-American family. The proband, a 28-year-old female, and her mother had a history of chronic anemia. One of her two brothers, who inherited the same gene defect, was apparently healthy with no symptoms of hemolytic anemia. The proband, her father, and her two brothers, including the one who carried the beta-globin gene rearrangement, were found to be heterozygous for alpha-thalassemia-2 (-alpha 3.7). Although the AGGC splice junction is disrupted (AGGC-->AGAT), the invariant AG has remained intact after this gene rearrangement. Our investigations could not detect any defect in RNA processing in the affected beta-globin genes. The discrepancies between the phenotypes and the globin chain synthesis ratios of the mother, her daughter, and her son who inherited the same gene defect at their beta-globin genes, remain unexplained.

Adult↗

Molecular heterogeneity of G-6-PD deficiency in Mexico.

DNA samples from seven G-6-PD deficient Mexican mestizo patients were analyzed. Three different G-6-PD genotypes were observed: G-6-PD A-202A/376G (three patients), G-6-PD A-376G/968C (three patients) and G-6-PD Seattle844C. The present results, along with previous reports, suggest not only G-6-PD A-genotypes are relatively common but also G-6-PD deficiency seems to be heterogeneous at DNA level in Mexico.

Africa↗

Gaucher disease.

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Bone Marrow Transplantation↗

Failure of alglucerase infused into Gaucher disease patients to localize in marrow macrophages.

BACKGROUND: Gaucher disease is a common glycolipid storage disease, caused by a deficiency of lysosomal beta-glucosidase (glucocerebrosidase). Alglucerase is a form of glucocerebrosidase enriched with terminal mannose moieties, so as to "target" the preparation to the high-affinity macrophage receptor in patients with Gaucher disease. Our earlier in vitro studies indicated that alglucerase was bound by cells other than macrophages by a widely distributed, low-affinity mannose receptor. MATERIALS AND METHODS: Bone was removed at surgery from six patients with Gaucher disease; in three cases, bone was obtainable both when the patient was untreated and after receiving an infusion of alglucerase. Four samples of bone were obtained from patients without Gaucher disease and served as controls. A bone marrow aspirate was obtained from another patient with Gaucher disease immediately after enzyme infusion. Marrow beta-glucosidase activity and chitotriosidase (a macrophage marker) was determined on all samples. RESULTS: Even with the large bolus doses used for the treatment of Gaucher disease by some, scarcely any beta-glucosidase activity was found in marrow samples; the amount of the enzyme was much less than would have been anticipated had the enzyme been evenly distributed to all body cells. CONCLUSIONS: Alglucerase is not targeted to marrow macrophages. Its unquestioned therapeutic effectiveness must be due either to its activity at some site other than marrow macrophages or to the fact that the doses administered are so enormous that even a small fraction is sufficient to achieve a therapeutic effect.

Bone Marrow↗

G6PD deficiency.

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Anemia, Hemolytic↗

Prenatal diagnosis of pyruvate kinase deficiency.

Prenatal testing for pyruvate kinase deficiency is often requested by parents who already have an affected child. However, before the development of molecular biologic techniques there were no suitable diagnostic methods. We present here two cases in which the diagnosis was established, one using amniotic fluid cells, the other cord blood. Two different approaches were used. The first, using a direct method of PCR amplification and restriction endonuclease analysis, detected mutations in fetus genomic DNA. The second method, using two polymorphic sites linked to the PKRL gene, enabled us to establish which chromosome had been inherited from each parent.

Anemia, Hemolytic, Congenital↗

Cladribine in treatment of chronic progressive multiple sclerosis.

Chronic progressive multiple sclerosis (MS) is a severely disabling demyelinating disease in which autoimmune processes seem to have a major role. The nucleoside drug cladribine is a potent lympholytic agent with few side-effects. We have studied its efficacy and safety in a randomised double-blind trial. 51 patients (48 entered as matched pairs) received four monthly courses of 0.7 mg/kg cladribine or placebo (saline) given through a surgically implanted central line. Neurologists with no knowledge of which medication the patient was receiving examined the patients monthly and noted two rating scale scores (Kurtzke and Scripps). Cerebrospinal fluid and brain magnetic resonance imaging (MRI) examinations were done at 6 and 12 months. Average neurological scores, demyelinated volumes on MRI, and concentrations of oligoclonal bands in cerebrospinal fluid were stable or improved in the patients receiving cladrabine but continued to deteriorate in patients on placebo. Mean paired (placebo minus matched cladribine) differences at 12 months relative to baseline were 1.0 (SE 0.4) for the Kurtzke scores, -13.9 (2.3) for the Scripps scores, 4.57 (1.17) mL for demyelinated volumes, and 7.3 (3.3) arbitrary units for concentrations of oligoclonal bands. Cladribine was generally well tolerated and clinically significant toxicity occurred in only 1 patient, in whom severe marrow suppression developed with complete recovery after several months. 1 patient died of newly acquired hepatitis B, an event unlikely to be related to cladribine. We conclude that the immunosuppressive drug cladribine influences favourably the course of chronic progressive MS.

Adult↗