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Biomedical subjects

J E Wraith

Publications and source records attributed to J E Wraith.

At least 19 recordsLinked to original sources

Facial appearance in glycogen storage disease type III.

Amylo-1,6-glucosidase deficiency (glycogen storage disease type III) is associated with hypoglycaemia, hepatomegaly, raised transaminases and in most cases skeletal myopathy and cardiomyopathy. The disorder has not been considered to cause dysmorphism. We report consistent facial features in seven patients with GSD type III consisting of midface hypoplasia with a depressed nasal bridge and a broad upturned nasal tip, indistinct philtral pillars, and bow-shaped lips with a thin vermillon border. Younger patients had in addition deepset eyes. Several children had clinical problems such as persistent otitis media or recurrent sinusitis. The underlying aetiology of these features is unknown but the similarity in all our patient suggests that there is a facial phenotype for this disorder.

Body Height↗

Enzyme replacement therapy in mucopolysaccharidosis type I: progress and emerging difficulties.

Mucopolysaccharidosis type I is due to a deficiency of the lysosomal enzyme alpha-L-iduronidase (EC 3.2.1.76) and is associated with a defect in the catabolism of the glycosaminoglycans heparan and dermatan sulphate. The clinical picture produced by this abnormal storage is diverse and ranges from a disorder that is fatal in the early months of life, due to cardiomyopathy, to a condition compatible with a normal life-span. It has become usual to describe the phenotypes associated with this spectrum of disorders after their eponymous names, Hurler (MPS IH, severe), Scheie (MPS IS, mild) and Hurler/Scheie (MPS IH/S, intermediate). Severely affected patients have progressive learning difficulties, facial and skeletal deformities, cardiac disease, corneal clouding, respiratory compromise and joint stiffness. Patients with MPS IH typically die in the first decade of life. MPS IH/S usually have normal intelligence and die in their twenties of cardiorespiratory disease. Patients with MPS IS may have joint stiffness, aortic valve disease and corneal clouding, but are often able to live a normal life-span. Enzyme replacement therapy has been developed as a potential therapy for some patients with MPS I. This process has been helped by the study of a naturally occurring canine model of the disease, which produces a phenotype similar to MPS IH/S in the human. This review details the progress that has been made in this area and also highlights some potential problems with the introduction of therapy.

Animals↗

Isolated splenomegaly as the presenting feature of Niemann-Pick disease type C.

WE DESCRIBE FOUR PATIENTS WITH NIEMANN: Pick disease type C (NPC), in whom the presentation was isolated splenic enlargement; this remained the only abnormality for a number of years. Diagnosis can be suggested by either finding abnormal storage material in a tissue biopsy specimen or by showing a modest elevation in plasma chitotriosidase activity. In patients with suggestive abnormalities, filipin staining of a skin fibroblast sample should confirm the abnormality in cholesterol trafficking. Formal esterification studies and mutation analysis should also be performed, especially if prenatal testing is to be performed in subsequent pregnancies. If the diagnosis is not considered and established, the family are at risk of having further affected children. Investigation of patients with isolated splenomegaly is not complete until NPC has been excluded.

Biopsy↗

Succinyl-CoA:3-ketoacid CoA transferase (SCOT): cloning of the human SCOT gene, tertiary structural modeling of the human SCOT monomer, and characterization of three pathogenic mutations.

The activity of succinyl-CoA:3-ketoacid CoA transferase (SCOT; locus symbol OXCT; EC 2.8.3.5) is the main determinant of the ketolytic capacity of tissues. Hereditary SCOT deficiency causes episodic ketoacidosis. Here we describe the human SCOT gene, which spans more than 100 kb and contains 17 exons, on chromosome 5p13. We report pathogenic missense mutations in three SCOT-deficient patients designated GS04, 05, and 06. GS04 is a G219E/G324E compound; GS05 is a V221M homozygote, and GS06 is a G324E homozygote. We constructed a tertiary structural model of human SCOT by homology modeling based on the known structure of Acidaminococcus fermentans glutaconate CoA transferase. The model predicts that V221 and G219 are on the dimerizing surface, whereas G324 is near the active site. SCOT activity was reduced to a comparable degree in all three patients, but in a transient expression assay in SCOT-deficient fibroblasts, cDNAs containing G219E and G324E produced no detectable activity, whereas V221M constructs yielded approximately 10% of the control peptide level and detectable specific activity. Interestingly, GS05 had the mildest clinical course reported to date and detectable levels of SCOT protein in fibroblasts.

Acidosis↗

Trifunctional protein deficiency: three families with significant maternal hepatic dysfunction in pregnancy not associated with E474Q mutation.

We report five families with trifunctional protein deficiency in which, during pregnancy, three mothers experienced significant hepatic disease when carrying an affected fetus. Diagnoses were based on increased levels of long-chain hydroxyacylcarnitines and deficiencies of 3-hydroxyacyl-CoA dehydrogenase (LCHAD) and 3-ketoacyl-CoA thiolase activity in fibroblasts. All affected infants lacked the common E474Q mutation associated with isolated LCHAD deficiency. This mutation is thought to be a predisposing factor for maternal hepatic disease in pregnancy. Our findings suggest that other defects in this enzyme complex might be responsible for maternal hepatic complications in pregnancy.

3-Hydroxyacyl CoA Dehydrogenases↗

Donor bone marrow from a sibling with inborn error of metabolism for treatment of acute leukaemia - clinical and biochemical consequences in the non-affected recipient.

Bone marrow transplantation (BMT) is increasingly used in an attempt to correct inborn errors of metabolism (IEM). However, little is known about effects of BMT from patients with IEM donating for non-affected recipients. We present data from a 8.5-year-old girl who underwent BMT in second remission for relapsed acute lymphoblastic leukaemia (ALL) at the age of 7 years from her HLA-identical brother who was severely affected by Hunter syndrome (Mucopolysaccharidosis type II, iduronate-2-sulphatase (IDS) deficiency). After BMT not only leukocyte but also plasma activity of IDS was absent. Mixing experiments and immunoadsorption suggest antibody-mediated enzyme inhibition. However, her urinary glycosaminoglycan excretion has not increased post BMT and clinical signs of mucopolysaccharidosis are absent 20 months after BMT. We conclude that patients with white cell enzyme deficiencies and other IEMs do not have to be excluded from bone marrow donation. Antibody production by the graft may occur and be reflected by a marked reduction in plasma enzyme levels but not tissue activity. Similar antibody responses resulting in enzyme inactivation might also affect other enzyme replacement strategies for individuals with IEM.

Acute Disease↗

Optic atrophy in association with cobalamin C (cblC) disease.

PURPOSE: To report the association of optic atrophy with cobalamin C (cblC) disease. METHODS: Descriptive case reports on three patients, two of whom were siblings. RESULTS: All three patients with cblC disease exhibited bilateral optic atrophy with decreased visual acuity. Of the two siblings, the younger sister had received cobalamin supplements from birth and the mother had been given cobalamin supplements prenatally. CONCLUSION: These three cases confirm the association of optic atrophy with cblC disease. Early treatment with cobalamin supplements does not appear to prevent the development of optic atrophy.

Age of Onset↗

Long-term follow-up following bone marrow transplantation for Hunter disease.

Bone marrow transplantation (BMT) was performed in 10 patients with Hunter disease (mucopolysaccharidosis type II, iduronate-2-sulphatase deficiency). The donor was an HLA-identical sibling in 2 cases, an HLA-nonidentical relative in 6 cases, a volunteer unrelated donor in 1 case, and details were not available in 1 case. Only three patients have survived for more than 7 years post BMT; however, this high mortality probably resulted from poor donor selection. In two, there has been a steady progression of physical disability and mental handicap. One patient has maintained normal intellectual development, with only mild physical disability. It is possible that BMT may be useful in selected patients with MPS II.

Adolescent↗

Generalised uridine diphosphate galactose-4-epimerase deficiency.

The generalised form of epimerase deficiency galactosaemia has been described in only two children from unrelated families. Their progress is reported and three other affected children from these families are described. The initial presentation was similar to classic galactosaemia. Despite treatment all have shown poor growth and moderate learning difficulties. Three have sensorineural deafness and four have pronounced dysmorphic features. The two older female patients have normal pubertal development.

Adolescent↗

Strategies for the treatment of cystathionine beta-synthase deficiency: the experience of the Willink Biochemical Genetics Unit over the past 30 years.

Strategies for the treatment of cystathionine beta-synthase (CBS) deficiency include (1) increasing residual enzyme activity by giving pyridoxine in those patients with vitamin responsive variants, (2) reducing the load on the affected pathway with a low methionine diet and supplementing the diet with cysteine; and (3) giving betaine in order to utilise alternative pathways to remove homocyst(e)ine. In our experience of over 30 years in the diagnosis and management of patients with CBS deficiency, a normal outcome can only be achieved in patients diagnosed and treated from infancy. Pyridoxine combined with folic acid prevents further deterioration in pyridoxine responsive patients. Dietary treatment of patients with non-pyridoxine responsive CBS deficiency becomes more difficult outside childhood but since late complications are not uncommon must be continued for life. Betaine can be effective in this group but compliance is often poor.

Adolescent↗

Mutation analysis in 57 unrelated patients with MPS II (Hunter's disease).

Genomic DNA from 57 unrelated MPS II (Hunter's disease) patients was analysed for mutations of the iduronate sulphatase (IDS) gene. The aim of the study was threefold: to identify the primary genetic lesion in patients, to investigate the correlation between genotype and phenotype, and most importantly, to provide reliable carrier testing for female members once the family mutation was identified. In 42 patients, point mutations were identified involving single base substitutions, deletions, or insertions. These included four new nonsense mutations (R8X, C84X, E245X, Y466X), six new missense mutations (D45N, N115Y, P228L, P266R, E434K, I485K, W502C), three new insertions (c70C71ins, c652C654ins, c709G710ins), six new deletions (c500delC, c705delC, c1023delA, c1049delA, c1141delC, c1576delG), and five new mutations involving splice sites (IVS1-2 a-->g, IVS2-10 t-->g, IVS5 + 2 t-->g L236L, IVS7 + 2 t-->c). One patient had a new seven base deletion in exon 9 (c1482-1488del). Four patients were shown to have complete deletions of the IDS gene and two deletions involved one or more exons. Previously described mutations present in these patients were Q80X, P86L, R172X, G374G, S333L, R443X, and R468Q. In eight patients, no mutation was detected throughout the entire coding region. Most mutations that result in MPS II appear to be unique. Absence of the probands' mutations in eight of nine maternal grandmothers suggests many mutations have arisen recently. Prediction of the clinical phenotype from the identified genotype was difficult in some families, and further studies using reverse transcription polymerase chain reaction are needed to confirm the predicted effects on the IDS mRNA suggested by genomic analysis.

Adolescent↗

Towards gene therapy of Hurler syndrome.

Allogeneic bone marrow transplantation is the most effective treatment for Hurler's syndrome. However, due to a lack of matched related donors and unacceptable morbidity of matched unrelated transplants, this therapy is not available to all patients. Therefore we have been developing an alternative approach based on transfer and expression of the normal gene in autologous bone marrow. A retroviral vector carrying the full length cDNA for alpha-L-iduronidase has been constructed and used to transduce bone marrow from patients with this disorder. A number of different gene transfer protocols have been assessed including the effect of intensive schedules of exposure of bone marrow to viral supernatant and the influence of growth factors. With these protocols we have demonstrated successful gene transfer into primitive CD34+ cells and subsequent enzyme expression in their maturing progeny. Also, using long-term bone marrow cultures, we have demonstrated high levels of enzyme expression sustained for several months. The efficiency of gene transfer has been assessed by PCR analysis of haemopoietic colonies as around 50%. No advantage has been demonstrated for the addition of growth factors or intensive viral exposure schedules. Indeed a possible disadvantage has been identified for the use of intensive transduction procedures. The enzyme is secreted into the medium and functional localisation has been demonstrated by reversal of the phenotypic effects of lysosomal storage in macrophages. This pre-clinical work forms the basis for a clinical trial of gene therapy for Hurler syndrome.

Bone Marrow Cells↗

Fourteen novel mucopolysaccharidosis IVA producing mutations in GALNS gene.

Mucopolysaccharidosis IVA (MPS IVA) is an autosomal recessive disorder caused by a deficiency of the lysosomal N-acetylgalactosamine-6-sulfate sulfatase. Here, we report our analysis of data on 21 patients of diverse ethnic and geographic origins studied by SSCP and sequencing analysis. Sixteen mutations were detected, including 14 new mutations (11 missense, one premature termination, one splice site alteration, and one cryptic site alteration). The donor splice site mutation (IVS4 + 1G-->A) predicts that normal splicing will be abolished and that translation would lead to an immediate premature termination (W141X). Another novel nucleotide change outside the coding sequence is an intronic alteration (IVS9-42C-->T:ggtcggtgcggttggtgc) creating a potential cryptic donor site. The nucleotide sequence surrounding this alteration is highly suggestive of a consensus donor splice site. All 12 missense and nonsense mutations were shown by transient expression to abolish or greatly reduce GALNS activity, thereby providing an explanation as to why they produce MPS IVA. All mutations were readily confirmed by restriction enzyme or by allelic specific oligonucleotide analysis (ASO). These findings, coupled with previously reported mutations, bring the total of different mutations to 41 among independent families with MPS IVA, illustrating the extensive allelic heterogeneity among mutations producing MPS IVA.

Chondroitinsulfatases↗