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A J Reuser

Publications and source records attributed to A J Reuser.

At least 37 records · Page 2Linked to original sources
PubMed1998

Glycogen storage disease type II: identification of a dinucleotide deletion and a common missense mutation in the lysosomal alpha-glucosidase gene.

In nine Dutch patients with the infantile form of glycogen storage disease type II (GSDII), who were compound heterozygous for either 525delT or exon18del (1), sequence analysis was performed to search for the mutations in the second lysosomal alpha-glucosidase allele. One patient had a novel TG deletion at cDNA position 379 + 380. Surprisingly five of the nine patients had the same two base pair changes: A921 --> T and G925 --> A. The first change is a well-known polymorphism but the second one is a novel mutation and results in the substitution of Gly309 by Arg. By screening 43 other GSDII patients the same mutation was found in two other cases, one from The Netherlands and one from France. To verify its deleterious effect, the mutation was introduced in the wild type lysosomal alpha-glucosidase cDNA and expressed in COS cells.

Alleles↗
PubMed1997

Mutation detection in glycogen storage-disease type II by RT-PCR and automated sequencing.

A new method is described for detection of mutations in the lysosomal alpha-glucosidase gene (GAA) leading to Glycogen Storage Disease type II (GSDII). A key feature of the method is isolation and reverse transcription of mRNA followed by PCR amplification of lysosomal alpha-glucosidase cDNA with M13-extended primers. Dye labeled primers are used for cycle sequencing and an ABI PRISM 377 DNA sequencing system for analysis. The method is rapid and complementary to the automated sequencing of all the 19, PCR amplified, coding exons of the GAA gene. The advantages and pitfalls of this new method are discussed in the light of the results obtained with an infantile GSDII patient. A new splice site mutation in the GAA gene of this patient was identified, IVS16(+2T-->C), resulting in the deletion of 16 base pairs of exon 16.

DNA, Complementary↗
PubMed1997

Two extremes of the clinical spectrum of glycogen storage disease type II in one family: a matter of genotype.

Mutation analysis was performed in a nonconsanguineous Dutch caucasian family with a grandfather presenting the first symptoms of glycogen storage disease type II (acid alpha-glucosidase deficiency) in the sixth decade of life and a grandchild with onset of symptoms shortly after birth. The grandfather was identified as compound heterozygote having the IVS1(-13T-->G)/delta T525 combination of mutant acid alpha-glucosidase alleles, the affected third generation offspring as homozygote delta T525/delta T525. The disease phenotypes in this family are in accordance with the genotypes since the IVS1(-13T-->G) mutation reduces acid alpha-glucosidase synthesis by 60 to 80%, whereas the delta T525 mutation completely prohibits the formation of catalytically active enzyme. Four additional families were identified with patients homozygote for delta T525 and five others with an equally deleterious delta T525/delta exon 18 genotype. The nine latter patients had typically the infantile form of glycogen storage disease type II. The genotype-phenotype correlation is irrefutable.

Female↗
PubMed1997

A novel acid alpha-glucosidase mutation identified in a Pakistani family with glycogen storage disease type II.

A novel mutation, C118T, in exon 2 of the acid alpha-glucosidase gene has been found in an infant with glycogen storage disease type II. This mutation is predicted to result in protein truncation. The phenotype was that of the severe infantile form of the disorder with lack of motor development, but with eye regard, social smile and vocalization. The parents were heterozygous for C118T and belong to an Islamic community opposed to termination of pregnancy. As the C118T mutation results in the loss of one of two AvaI sites present in an informative PCR product, reliable premarriage carrier detection became possible and was acceptable to the members of this extended family.

Bronchopneumonia↗
PubMed1996

Expression of cDNA-encoded human acid alpha-glucosidase in milk of transgenic mice.

Enzyme replacement therapy is at present the option of choice for treatment of lysosomal storage diseases. To explore the feasibility of lysosomal enzyme production in milk of transgenic animals, the human acid alpha-glucosidase cDNA was placed under control of the alpha S1-casein promoter and expressed in mice. The milk contained recombinant enzyme at a concentration up to 1.5 micrograms/ml. Enzyme purified from milk of transgenic mice was internalized via the mannose 6-phosphate receptor and corrected enzyme deficiency in fibroblasts from patients. We conclude that transgenically produced human acid alpha-glucosidase meets the criteria for therapeutic application.

Animals↗
PubMed1996

Lysosomal alpha-glucosidase: cell-specific processing and altered maturation in HT-29 colon cancer cells.

We have previously described the abnormal localization of resident Golgi proteins and O-glycans in the rough endoplasmic reticulum of mucin-secreting HT-29 M6 colon cancer cells, suggesting altered protein trafficking in these cells [Egea, Francí, Gambús, Lesuffleur, Zweibaum and Real (1993) J. Cell Sci. 105, 819-830]. In the present work, we have chosen lysosomal alpha-glucosidase as a reporter to examine the intracellular traffic of glycoproteins in M6 cells. We have compared the synthesis and processing of alpha-glucosidase in mucin-secreting M6 cells and in Caco-2 colon cancer cells, the latter resembling normal absorptive intestinal epithelium. Our results show that alpha-glucosidase processing and secretion is markedly delayed in M6 cells as compared to Caco-2 cells or normal fibroblasts, and this delay is caused by an accumulation of alpha-glucosidase precursor form in the trans-Golgi network. Furthermore, treatment in Caco-2 cells with brefeldin A led to changes in alpha-glucosidase maturation similar to those observed in untreated M6 cells. To determine whether altered processing occurs in other cultured cells, a panel of cancer cell lines and cultures from normal exocrine pancreas were examined. In pancreas-derived cultures, alpha-glucosidase showed a processing pattern different from that described until now. Only HT-29 cells and HT-29-derived subpopulations displayed a defect in alpha-glucosidase maturation. In conclusion, alpha-glucosidase processing is more diverse than has previously been described; this finding may have tissue-specific functional implications.

Amidohydrolases↗
PubMed1996

Asymptomatic and late-onset ornithine transcarbamylase (OTC) deficiency in males of a five-generation family, caused by an A208T mutation.

In a large five-generation Polish family, late-onset ornithine transcarbamylase (OTC) deficiency in males segregated with the missense mutation Ala208Thr (A208T), and all heterozygous females were asymptomatic. No other mutations were found in the coding sequences and intron-exon boundaries of the OTC gene. Surprisingly, the mutation originated from the great-grandfather of the index patient who died at age 59 of liver carcinoma. He never had dietary restrictions or hyperammonemic spells throughout life and appears to be the oldest male reported with OTC deficiency. The index patient had a severe OTC deficiency (3% of normal). Eight males died suddenly at ages 4 months to 23 years (average 14 years) after a foudroyant episode triggered by a common infection. The patients remained undiagnosed for 28 years because a metabolic defect was not considered to be the cause of the acute episodes. Recognition of the familial pattern of inheritance was initially unnoticed since the patients were admitted to eight different hospitals. DNA analysis predicted that two 'healthy' boys also had OTC deficiency, which was confirmed by abnormal results of allopurinol challenge tests. Initial suspicion of OTC deficiency in such families is complicated, since symptoms can develop at any age, or even remain absent. This obscures the typical pattern of X-linked inheritance in small families.

Age of Onset↗
PubMed1996

Homozygous deletion of exon 18 leads to degradation of the lysosomal alpha-glucosidase precursor and to the infantile form of glycogen storage disease type II.

We describe two unrelated Dutch patients with typical symptoms of infantile glycogen storage disease type II (GSD II) and virtual absence of acid alpha-glucosidase activity in leukocytes and cultured skin fibroblasts. The patients were identified as homozygotes for a deletion of exon 18 of the acid alpha-glucosidase gene (GAA). The in-frame deletion manifests at the protein level in a characteristic way: the enzyme precursor is smaller than normal and degraded in the endoplasmic reticulum or Golgi complex. These case present an evident example of a genotype-phenotype correlation in glycogen storage disease type II.

Chromosome Deletion↗
PubMed1996

Human alpha-N-acetylgalactosaminidase (alpha-NAGA) deficiency: new mutations and the paradox between genotype and phenotype.

Up to now eight patients with alpha-NAGA deficiency have been described. This includes the newly identified patient reported here who died unexpectedly aged 1 1/2 years of hypoxia during convulsions; necropsy was not performed. Three patients have been genotyped previously and here we report the mutations in the other five patients, including two new mutations (S160C and E193X). The newly identified patient is consanguineous with the first patients reported with alpha-NAGA deficiency and neuroaxonal dystrophy and they all had the alpha-NAGA genotype E325K/E325K. Clinical heterogeneity among patients with alpha-NAGA deficiency is extreme. Two affected sibs, homozygotes for E325K, are severely affected and have the signs and symptoms of infantile neuroaxonal dystrophy, but prominent vacuolisation is lacking. The mildly affected patients (two families, three patients) at the opposite end of the clinical spectrum have clear vacuolisation and angiokeratoma but no overt neurological manifestations. Two of them are homozygous for the stop mutation E193X, leading to complete loss of alpha-NAGA protein. These observations are difficult to reconcile with a simple genotype-phenotype correlation and we suggest that factors or genes other than alpha-NAGA contribute to the clinical heterogeneity of the eight patients with alpha-NAGA deficiency. At the metabolic level, the patients with alpha-NAGA deficiency are similar. The major abnormal urinary oligosaccharides are sialylglycopeptides of the O linked type. Our enzymatic studies indicated that these compounds are not the primary lysosomal storage products.

Animals↗
PubMed1995

Isolation and characterisation of a recombinant, precursor form of lysosomal acid alpha-glucosidase.

Glycogenosis type II (GSD II, Pompe disease) is an autosomal recessive lysosomal storage disease that results from a deficiency of acid alpha-glucosidase (GAA). Patients with this disorder are unable to break down lysosomal glycogen, which consequently accumulates in the lysosome. To evaluate enzyme replacement therapy for GSD II patients, we have expressed human GAA cDNA in Chinese hamster ovary-K1 cells utilising a vector that places the cDNA under the transcriptional control of the human polypeptide chain elongation factor 1 alpha gene promoter. A clonal cell line that secreted precursor recombinant GAA at approximately 18 mg.l-1.day-1 was identified. The precursor recombinant GAA was purified to homogeneity, had a molecular mass of 110 kDa as measured by SDS/PAGE, and was shown to have pH optima and kinetic parameters similar to those of GAA purified from human tissues. The partial N-terminal amino acid sequence of recombinant GAA conformed to that derived from the nucleotide sequence of the cloned cDNA. The recombinant enzyme was taken up by cultured fibroblasts and skeletal muscle cells from GSD II patients, and was shown to correct the storage phenotype. Endocytosed GAA was localised to the lysosome and showed evidence of intracellular processing to a more mature form. Activity levels increased up to twice the normal value and uptake was prevented if cells were cultured in the presence of mannose 6-phosphate.

Amino Acid Sequence↗
PubMed1995

Genotype-phenotype correlation in adult-onset acid maltase deficiency.

We performed a clinical, biochemical, and genetic study in 16 patients from 11 families with adult-onset acid maltase deficiency. All patients were compound heterozygotes and carried the IVS1(-13T --> G) transversion on one allele; the second allele harbored either a deletion of a T at position 525 in exon 2 (7 probands, 64%) or a deletion of exon 18 (1 proband, 9%). Deterioration of handicap was related to age, and decrease in vital capacity to duration of the symptomatic stage. Respiratory insufficiency was never the first manifestation. The levels of activity of serum creatine kinase and of alpha-glucosidase in peripheral blood cells or muscle were helpful for the diagnosis, but did not have prognostic value. The adult form of acid maltase deficiency appears to be both clinically and genetically rather homogeneous; decrease of alpha-glucosidase activity is the final common pathway leading to destruction of muscle fibers and progression of muscle weakness over a period of years.

Adolescent↗
PubMed1995

Glycogenosis type II (acid maltase deficiency).

Glycogen storage disease type II (GSD II/glycogenosis type II/Pompe's disease/acid maltase deficiency) is caused by the deficiency of lysosomal alpha-glucosidase resulting in lysosomal accumulation of glycogen. The disease is inherited as an autosomal recessive trait and is clinically heterogeneous. Early and late onset phenotypes are distinguished. Insight in the molecular nature of the lysosomal alpha-glucosidase deficiency and the underlying genetic defect has increased significantly during the past decade. This minireview on GSD II was written at the occasion of The International Symposium on Glycolytic and Mitochondrial Defects in Muscle and Nerve, held in Osaka, Japan, July 1994. It is an update of current literature, but also includes original data from the collaborating authors on mutations occurring in the lysosomal alpha-glucosidase gene and on prenatal diagnosis by chorionic villus sampling. The genotype-phenotype correlation and the prospects for therapy are addressed.

Glucan 1,4-alpha-Glucosidase↗
PubMed1995

Characterization of FMR1 proteins isolated from different tissues.

FMR1 protein expression was studied in different tissues. In human, monkey and murine tissues, high molecular mass FMR1 proteins (67-80 kDa) are found, as shown in lymphoblastoid cells lines. The identity of these proteins was confirmed by their absence in tissues from patients with the fragile X syndrome and a FMR1 knock-out mouse. An Ile367Asn substitution in the FMR1 protein did not alter the translation, processing and localization of FMR1 proteins in lymphoblastoid cells from a patient carrying this mutation. All the high molecular mass FMR1 proteins isolated from normal lymphoblastoid cells and cells from the patient with the Ile367Asn substitution were able to bind RNA. However, the FMR1 proteins of the patient had reduced affinity for RNA binding at high salt concentrations. In some human, monkey and murine tissues low molecular mass FMR1 proteins (39-41 kDa) were found, which had the same N terminus as the 67-90 kDa isoforms, but differ in their C terminus and are therefore most likely the result of carboxy-terminal proteolytic cleavage. These low molecular mass FMR1 proteins did not bind RNA, in contrast with the high molecular mass FMR1 proteins. The significance of these low molecular mass proteins remains to be studied.

Animals↗
PubMed1995

Prenatal diagnosis of glycogen storage disease type II: enzyme assay or mutation analysis?

Two mutations in the lysosomal alpha-glucosidase gene, a single base pair deletion (delta T525) and a deletion of exon 18, have recently been identified with a relatively high incidence in Caucasian patients with glycogen storage disease type II (GSD II). Prenatal diagnosis was made in a pregnancy of consanguineous parents of a child with GSD II. The delta T525 deletion was demonstrated in this family but unexpectedly in only one of the parents. The absence of the delta T525 deletion in DNA isolated from the chorionic villi and a normal alpha-glucosidase activity indicated that the fetus was not affected. The possible role of mutation analysis in the prenatal diagnosis of GSD II is discussed in the light of our previous experience from a series of 100 prenatal diagnoses for this disorder by enzyme analysis.

Base Sequence↗
PubMed1995

A biochemical and immunocytochemical study on the targeting of alglucerase in murine liver.

A current hypothesis is that functional glucocerebrosidase needs to be delivered to the lysosomes of tissue macrophages to guarantee successful enzyme therapy for Gaucher's disease. In this study, biochemical and immunohistochemical techniques were applied to identify in mice the localization of intravenously administered alglucerase (human modified placental glucocerebrosidase). Only in liver and spleen was a significant increase of glucocerebrosidase activity observed, with a maximum level at 15 minutes after enzyme infusion. The uptake of enzyme by liver was sufficiently high to allow more detailed studies on the (sub)cellular distribution of human alglucerase. The enzyme in liver is localized both in the endosomal-lysosomal system of the Kupffer cells and the endothelial cells lining the lumen of the sinusoids. Uptake by both of these types of cell is prevented by mannan. The results suggest that the cellular mechanisms responsible for improvement of Gaucher patients receiving alglucerase treatment is probably more complicated than previously recognized.

Animals↗
PubMed1994

Deletion of exon 18 is a frequent mutation in glycogen storage disease type II.

An abnormal 2.3 kb SacI fragment of the human lysosomal alpha-glucosidase gene (GAA) was identified in patients with glycogen storage disease type II. The fragment results from deletion of exon 18 and adjacent parts of intron 17 and 18. The borders of the deletion are marked by the occurrence of an eight nucleotide long tandem repeat (AGGGGCCG) which is apparently instrumental in the mutation event. The exon 18 deletion was demonstrated in 10 out of 39 patients from Europe (all hetero-allelic) and is so far the most common mutation in this disease (allele frequency among patients is 0.13).

Base Sequence↗
PubMed1994

The effect of a single base pair deletion (delta T525) and a C1634T missense mutation (pro545leu) on the expression of lysosomal alpha-glucosidase in patients with glycogen storage disease type II.

Glycogen storage disease type II (GSDII, Pompe's disease) is caused by an autosomal recessive inheritance of lysosomal alpha-glucosidase deficiency. By sequence analysis we have identified the mutations in the lysosomal alpha-glucosidase gene (GAA) of two unrelated patients, who have one and two copies, respectively, of the same missense mutation. The milder affected adult patient was found to be homozygous for a C1634T transition resulting in the substitution of pro545 by leu. The more severely affected adolescent patient had this same mutant allele combined with a 1 base pair deletion (delta T525) in the second allele causing premature termination at nucleotide positions 658-660. Both these mutations were introduced in wild-type alpha-glucosidase cDNA and expressed in COS-1 cells to analyse their effect. The delta T525 mutation prohibits the formation of lysosomal alpha-glucosidase completely. The pro545-->leu substitution is compatible with normal synthesis but hampers enzyme maturation and results in a 92% net loss of lysosomal alpha-glucosidase activity. The patient with adult GSDII has, in accordance with the allelic constitution, a 2-fold higher residual activity than the patient with juvenile GSDII. The delta T525 deletion was detected in two other unrelated patients, and also the C1634T transition was encountered in two more Caucasian patients with GSDII.

Adolescent↗