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Biomedical subjects

J E Wraith

Publications and source records attributed to J E Wraith.

At least 73 records · Page 4Linked to original sources

Anaesthesia and mucopolysaccharidoses. A review of airway problems in children.

The airway problems encountered during anaesthesia in all children with mucopolysaccharidoses presenting for a surgical procedure from 1988 to September 1991 are reviewed. Thirty-four patients underwent 89 anaesthetics for 110 procedures. The results reveal a high incidence of airway problems. The overall incidence of difficult intubation was 25% and failed intubation 8%. In those children with Hurler's syndrome, the difficult intubation incidence was 54% and failed intubation incidence 23%. Other potential anaesthetic problems such as cardiac anomalies and obstructive sleep apnoea are also reviewed.

Adolescent↗

Long-term clinical progress in bone marrow transplanted mucopolysaccharidosis type I patients with a defined genotype.

Two mucopolysaccharidosis type I (MPS-I) patients, subjected to bone marrow transplantation (BMT) more than 10 years ago, have recently had their alpha-L-iduronidase genotypes defined. Both patients, homozygous for the relatively common W402X mutation, received BMT when they were 14 and 11 months of age, and are now 12 and 14 years old, respectively. Untreated MPS-I patients, homozygous for W402X, have an extremely severe clinical phenotype with rapid clinical deterioration and death before 6 years of age. The 12-year-old patient, with limited mobility, is coping well at school, while the other patient is wheelchair-bound with severe disability in his lower limbs, and attends a school for the physically handicapped. Both patients have less than normal intelligence with slowly continuing losses. A third MPS-I patients, diagnosed at the age of 6 months, was felt, prior to BMT at 14 months, to have a severe phenotype. Twelve years post-BMT, he is ambulatory, albeit with restricted movement, and has normal intelligence. This patient did not have a defined MPS-I genotype and had alpha-L-iduronidase protein and activity consistent with a less severe outcome than the first two patients. We conclude that BMT has significantly slowed down the clinical regression of the W402X phenotype. We propose that if further gains are to be made, BMT should be performed within the first few months of life. Early diagnosis is therefore essential.

Adolescent↗

Combined deficiencies of the pyruvate dehydrogenase complex and enzymes of the respiratory chain in mitochondrial myopathies.

In six patients with mitochondrial (encephalo-) myopathy investigations of skeletal muscle revealed a defect of pyruvate dehydrogenase complex (PDHC) in combination with one or more respiratory chain complex deficiencies. A combination of defects of this kind has not been reported previously. Five of the six patients presented within the 1st year of life and had a severe clinical course. Intrafamilial variability of the clinical course in dizygotic twins both suffering from a cytochrome c oxidase deficiency and one of them also from a PDHC deficiency suggests an additional effect of PDHC deficiency on the clinical symptoms. Immunoblot studies of PDHC in five of the patients revealed no abnormalities in their subunit pattern, rendering a defect of mitochondrial protein import or assembly unlikely. The finding of a combined PDHC and respiratory chain deficiency has implications for the diagnostic approach, for therapy and genetic counselling. The exact pathogenetic mechanism of this combination of defects remains to be elucidated.

Female↗

Mucopolysaccharidosis type I (Hurler syndrome): linkage disequilibrium indicates the presence of a major allele.

Two polymorphisms exist in the alpha-L-iduronidase (IDUA) gene, the gene that is defective in mucopolysaccharidosis type I (MPS I), viz. a KpnI polymorphism and a variable number of tandem repeats (VNTR) polymorphism with three common alleles. The analysis of allele and haplotype frequencies for these two polymorphisms in the normal population and in MPS I patients revealed the presence of linkage disequilibrium. The frequency of the 2,2 (VNTR, KpnI) allele in MPS I patients was 57% compared with only 37% in the normal population. The implications for the presence of a major MPS I allele and the ability to predict patient phenotype are discussed.

Alleles↗

First-trimester diagnosis of Hunter syndrome: very low iduronate sulphatase activity in chorionic villi from a heterozygous female fetus.

Iduronate sulphatase activity was determined in uncultured chorionic villi from four fetuses at risk for Hunter syndrome. All fetuses were shown to be female by chromosome analysis. Biopsy material from three fetuses showed iduronate sulphatase activity within normal limits whilst the fourth fetus showed activity reduced to 7 per cent of our control mean. The importance of fetal sexing in prenatal diagnosis of this condition is emphasized as female carrier fetuses may show iduronate sulphatase activity reduced to levels observed in affected males.

Chorionic Villi Sampling↗

Frequent deletions at Xq28 indicate genetic heterogeneity in Hunter syndrome.

Hunter syndrome is a human X-linked disorder caused by deficiency of the lysosomal exohydrolase iduronate-2-sulphatase (IDS). The consequent accumulation of the mucopolysaccharides dermatan sulphate and heparan sulphate, in the brain and other tissues, often results in death before adulthood. There is, however, a broad spectrum of severity that has been attributed to different mutations of the Hunter syndrome gene. We have used an IDS cDNA clone to localise the IDS gene to Xq28, distal to the fragile X mutation (FRAXA). One-third of Hunter syndrome patients had various deletions or rearrangements of their IDS gene, proving that different mutations are common in this condition. Deletions of the IDS gene can include a conserved locus that is tightly linked to FRAXA, suggesting that deletion of nearby genes may contribute to the variable clinical severity noted in Hunter syndrome. The cDNA clone was also shown to span the X chromosome breakpoint in a female Hunter syndrome patient with an X;autosome translocation.

Blotting, Southern↗

The clinical phenotype of two patients with a complete deletion of the iduronate-2-sulphatase gene (mucopolysaccharidosis II--Hunter syndrome).

Two patients with a complete deletion of the iduronate-2-sulphatase (IDS) gene are described. In both patients, the resulting phenotype was that of very severe Hunter syndrome (mucopolysaccharidosis II). In addition, both had features not commonly seen in this disorder, e.g. early onset of seizures in one patient and ptosis in the other. It is speculated that loss of adjacent loci may contribute to the unusual findings and that the severe features present in both patients may represent contiguous gene syndromes. Further analysis of IDS cDNA from other patients with Hunter's syndrome may eventually enable phenotype to be predicted more accurately.

Blotting, Southern↗

beta-mannosidase deficiency in a female infant with epileptic encephalopathy.

We report a female infant with an isolated deficiency of beta-mannosidase activity. At nine months of age dysmorphism was absent except for brachecephaly. There was moderate developmental delay and a startle response to sound. At 12 months there was a sudden onset of tonic-clonic seizures which were unresponsive to drug therapy, requiring paralysis and mechanical ventilation for control. The child died suddenly aged 15 months. beta-mannosidase activity was markedly reduced in white cells and cultured skin fibroblasts whilst other lysosomal enzymes were normal. The disaccharide ManGlcNAc was excreted in urine but urinary mucopolysaccharides were normal.

Abnormalities, Multiple↗

No sensory neuropathy during pyridoxine treatment in homocystinuria.

Seventeen patients with cystathionine synthase deficiency homocystinuria were examined clinically and neurophysiologically for evidence of sensory neuropathy. All had received high dose pyridoxine (vitamin B-6) for many years. Absence of neurological disturbance in all cases suggests long term treatment with pyridoxine in the dosages used in homocystinuric patients is not harmful.

Adolescent↗

Geleophysic dysplasia.

We describe 2 children with geleophasic dysplasia. Prominent cardiac disease in one of the patients caused death at an early age. The history of consanguinity in one of the families supports autosomal recessive mode of inheritance. Histological and ultrastructural changes suggest that a disturbance in the relations between cell membrane and extracellular matrix may be involved in the pathogenesis.

Abnormalities, Multiple↗

Carpal tunnel syndrome in the mucopolysaccharidoses and related disorders.

Eighteen patients with various mucopolysaccharidoses or mucolipidosis III were studied electrophysiologically to determine the presence or absence of carpal tunnel syndrome. In 17 patients this was clearly demonstrated, the only exception being a boy with mucopolysaccharidosis II, age 6 months at testing. All patients had a remarkable lack of symptoms. Carpal tunnel syndrome is a very common complication of the mucopolysaccharidoses and mucolipidosis III and should be actively looked for in affected patients. Early diagnosis and treatment offer the best chance of a good response to surgery.

Adolescent↗

A clinician's view of the mass screening of the newborn for inherited diseases: current practice and future considerations.

The case for or against mass screening for inherited diseases is discussed. There is universal acceptance for mass screening for phenylketonuria and congenital hypothyroidism. The case for mass screening for galactosaemia and for maple syrup urine disease is not very strong; they could be considered under the heading of 'urgent screening of the sick newborn'. It is difficult to find good arguments for mass screening for congenital adrenal hyperplasia. For screening for glucose-6-phosphate dehydrogenase deficiency and sickle cell disease, the established criteria for mass screening do not apply. A simple tool for early detection is now available and the population afflicted with a mutant gene which causes major health problems should receive special attention from its government. It is too early to offer any comment about cystic fibrosis screening; further developments must be awaited.

Cystic Fibrosis↗

Sulfite oxidase deficiency: clinical, neuroradiologic, and biochemical features in two new patients.

Sulfite oxidase deficiency is characterized by severe neurologic dysfunction, dislocation of the lenses, and the accumulation and excretion of inorganic sulfite, thiosulfate, and S-sulfocysteine. We present the clinical, radiologic, and biochemical findings in two patients with this condition. In both, neurologic problems started soon after birth and progressed rapidly to profound mental retardation, microcephaly, blindness, and spastic quadriparesis. Seizures were a persistent problem throughout the course of their illness. The neurologic abnormalities were associated with progressive destruction of brain tissue. We established the diagnosis of sulfite oxidase deficiency by demonstrating the characteristic abnormal metabolites in urine. However, commonly used screening procedures do not detect these compounds, and dislocation of the lenses is usually a late feature of the disease. As a result, the diagnosis may be easily overlooked, especially during infancy. Specific investigations for sulfite oxidase deficiency are indicated for any baby with severe, progressive neurologic disease.

Atrophy↗