PubMed Health⌕ Search

Biomedical subjects

D Gardner-Medwin

Publications and source records attributed to D Gardner-Medwin.

At least 37 records · Page 2Linked to original sources
PubMed1993

The clinical, genetic and dystrophin characteristics of Becker muscular dystrophy. I. Natural history.

We have investigated 67 patients with proven Becker muscular dystrophy (BMD) using a standard protocol including a detailed history and a functional and clinical examination. Our aim was to define the natural history of the disease in a large cohort of patients in the light of the diagnostic methods now available. In all patients with or without an X-linked family history, the diagnosis was confirmed by the identification of a deletion or other abnormality in the dystrophin gene, and abnormal dystrophin on immunoblotting and immunocytochemistry of muscle biopsy samples. In graphs of functional and muscle score against age, two groups of patients emerged. In the larger group the disease was milder and patients remained ambulant into their forties or beyond. A smaller group had more severe disease with a slightly earlier onset, much earlier loss of ambulation, more frequent abnormal electrocardiographic findings and much lower reproductive fitness. The relationship of these clinical findings to the genetic and protein abnormalities found in the patients is explored in the accompanying paper.

Adolescent↗
PubMed1993

The clinical, genetic and dystrophin characteristics of Becker muscular dystrophy. II. Correlation of phenotype with genetic and protein abnormalities.

We have correlated a detailed clinical assessment of 67 patients with proven Becker muscular dystrophy with the results from genetic and protein analyses. There was an overall deletion frequency of 80%, rising to 92.6% in the large group of patients defined on clinical grounds as being of "typically" mild severity. The deletions in this group were all clustered in the region of the gene between exons 45 and 59; the most common deletion was of exons 45-47 and all but one started at exon 45. No similar deletions were seen in the patients with more severe disease, in whom the diverse genetic defects included a duplication and a very large deletion. Dystrophin patterns in the "typical" group were also very characteristic, and in both groups were as predicted from the genetic defect, the size of deletions being inversely proportional to the size of the protein produced.

Adolescent↗
PubMed1993

Variability in clinical, genetic and protein abnormalities in manifesting carriers of Duchenne and Becker muscular dystrophy.

We have analysed the results of clinical assessment, X-inactivation status, deletion screening and dystrophin analysis in eight manifesting carriers of Duchenne and Becker muscular dystrophy (DMD and BMD). Only two had a prior family history of X-linked muscle disease, all had normal karyotypes and none were twins. Presentation varied from 2 to 25 yr and progression varied from a DMD-like severity to a very mild BMD-like course. In one girl the initial symptoms were restricted to learning difficulties. Where methods for assessing X-inactivation were informative, three patients showed an abnormal pattern. However, in one patient, the obligate carrier daughter of a BMD patient who had presented at the age of 2 yr, X-inactivation appeared normal in lymphocytes and muscle. While dystrophin analysis seems to be reliable in identifying manifesting carriers of DMD and BMD, the relationship between X-inactivation status, dystrophin analysis and phenotype is not simple.

Adolescent↗
PubMed1993

Dystrophin expression in Duchenne patients with "in-frame" gene deletions.

Details of disease progression and dystrophin expression are presented for three patients with Duchenne muscular dystrophy (DMD) who unexpectedly had intragenic deletions which maintained the open reading frame for mRNA translation. Analysis of dystrophin in muscle biopsies showed variable dystrophin synthesis in all three patients. Two with relatively small deletions (missing exons 10-13 and 52-55) had low levels of dystrophin which were comparable to those found in many DMD patients. The third patient (with a larger deletion which removed exons 3-25) produced dystrophin in the high abundance which is normally associated with patients who have Becker muscular dystrophy. This is the first time that a patient has been described with the clinical phenotype of DMD, a large amount of dystrophin which was correctly localized at the periphery of muscle fibres and an in-frame deletion of exons in the amino terminal domain.

Biopsy↗
PubMed1993

Congenital livedo reticularis and recurrent stroke-like episodes.

Three children with pronounced livedo reticularis present since birth (cutis marmorata-telangiectasia congenita) have been followed to the ages of eight, 17 and 21 years. During childhood they developed frequent recurrent transient stroke-like hemipareses, affecting either side of the body, associated with ipsilateral pain, headache, visual symptoms, dysphasia, fits and confusion. Intellectual failure and, in one, progressive spasticity have followed. Attacks were more frequent in winter. Other problems have included abnormal peripheral vascular responses to temperature change, gastro-intestinal bleeding, glaucoma, local tissue hypertrophy and, in the two older patients, renal involvement with hypertension. Their condition represents a form of congenital vasculopathy. Anticonvulsants, anti-migraine agents, anti-platelet drugs and flunarizine have been ineffective. Nifedipine prevented further attacks in one patient and reduced attacks in another, but has not helped the third child. Adequate clothing and warmth may also be important.

Adult↗
PubMed1993

Functional significance of dystrophin positive fibres in Duchenne muscular dystrophy.

The age when boys lose the ability to walk independently is one of the milestones in the progression of Duchenne muscular dystrophy (DMD). We have used this as a measure of disease severity in a group of 30 patients with DMD and six patients with intermediate Duchenne/Becker dystrophy (D/BMD). Dystrophin analysis was performed on tissue sections and western blots of muscle biopsy specimens from these patients and the relationships that were found between clinical severity and abundance of dystrophin labelling are reported. All patients with intermediate D/BMD had dystrophin labelling that was detected on sections and blots. Weak dystrophin labelling was found in sections from 21/30 DMD cases and on blots in 18/30 cases. Two non-exclusive patterns of dystrophin labelling were observed on sections: very clear labelling on a small percentage of fibres (usually < 1%) or very weak labelling on a much higher proportion (about 25%). The mean age at loss of mobility among the DMD patients with no dystrophin labelling on tissue sections was 7.9 years (range 6.3-9.5) while the mean age among those with some labelling was 9.9 years (range 8.0-11.9); this is a significant difference. Quantitative estimates of dystrophin abundance were obtained from densitometric analysis of dystrophin bands on blots. In the whole group of 36 patients, a significant positive relationship was found between the abundance of dystrophin and the age at loss of independent mobility. It is concluded that even the very low concentrations of dystrophin found in DMD patients may have some functional significance.

Adolescent↗
PubMed1993

Orofaciodigital syndrome type III in two sibs.

A brother and sister with mental retardation, malformations of the cerebellar vermis, characteristic 'metronome' eye movements, lingual hamartomas, and postaxial polydactyly are described. The clinical overlap with the OFD group of syndromes, in particular OFD III and OFD VI, and Joubert's syndrome is discussed. If OFD III syndrome is to be recognised as a distinct entity, these two cases represent the second and third cases reported.

Child↗
PubMed1993

Two new mutations in a late infantile Tay-Sachs patient are both in exon 1 of the beta-hexosaminidase alpha subunit gene.

We have identified two new point mutations in the beta-hexosaminidase alpha subunit (HEX A) gene in a non-Jewish Tay-Sachs disease patient with an unusual late infantile onset disease phenotype. The patient was a compound heterozygote with each allele of the HEX A gene containing a different mutation in exon 1. One of these is a T to C transition in the initiation codon, expected to produce no alpha subunit and therefore a classical infantile phenotype. The unusual clinical aspects and later onset in the patient must therefore be a result of residual hexosaminidase A activity associated with a mutant alpha subunit containing the second mutation, substitution of serine for proline at amino acid 25 owing to a C to T change at nucleotide 73. Western blotting and DE-52 ion exchange chromatography have been used to examine the behaviour of this mutant alpha subunit.

Amino Acid Sequence↗
PubMed1993

Integrated study of 100 patients with Xp21 linked muscular dystrophy using clinical, genetic, immunochemical, and histopathological data. Part 1. Trends across the clinical groups.

This multidisciplinary study was undertaken to record the variation in gene and protein expression in a large cohort of patients with well defined clinical phenotypes. The patients, whose ages ranged from 4 years to 66 years, spanned a wide range of disease severity. They represented the first 100 patients who had been examined in Newcastle, had undergone a muscle biopsy, and provided a blood sample for DNA analysis. The study had three aims: to observe any trends in the analyses across the clinical groups, to correlate gene and protein expression in individual patients, and to use the data collected to assess the relative usefulness of different techniques in the diagnosis and prognosis of patients with Duchenne and Becker dystrophy (DMD/BMD). In part 1, we describe the clinical assessment of the patients and the trends that were observed across the cohort. The patients were divided into seven groups. Group 1 had severe DMD (n = 21), group 2 had milder DMD (n = 20), group 3 were intermediate D/BMD patients (n = 9), group 4 had severe BMD (n = 5), and group 5 were more typical BMD patients (n = 31). Some patients were too young to be classified (n = 7) and a group of all the female patients were also classified separately (n = 7). The number of DMD and BMD patients was about equal, in accord with disease prevalence in the north of England, but an unusually high proportion were sporadic cases. Dystrophin labelling (performed with up to three antibodies) on both blots and sections increased gradually across the clinical groups. All histopathological indices, except the proportion of fat in biopsy sections, showed clear trends across the groups.

Adolescent↗
PubMed1993

Integrated study of 100 patients with Xp21 linked muscular dystrophy using clinical, genetic, immunochemical, and histopathological data. Part 2. Correlations within individual patients.

This report is the second part of a trilogy from a multidisciplinary study which was undertaken to record the relationships between clinical severity and dystrophin gene and protein expression. The aim in part 2 was to correlate the effect of gene deletions on protein expression in individual patients with well defined clinical phenotypes. Among the DMD patients, most of the deletions/duplications disrupted the open reading frame, but three patients had in frame deletions. Some of the intermediate D/BMD patients had mutations which were frameshifting while others were in frame. All of the deletions/duplications in the BMD patients maintained the open reading frame and 25/26 deletions in typical BMD group 5 started with exon 45. The deletion of single exon 44 was the most common mutation in patients from groups 1 to 3. Dystrophin was detected in sections and blots from 58% of the DMD patients with a size that was compatible with synthesis from mRNA in which the reading frame had been restored. Certain deletions were particularly associated with the occurrence of limited dystrophin synthesis in DMD patients. For example, 9/11 DMD patients missing single exons had some detectable dystrophin labelling compared with 10/24 who had deletions affecting more than one exon. All patients missing single exon 44 or 45 had some dystrophin. Deletions starting or finishing with exons 3 or 51 (8/9) cases were usually associated with dystrophin synthesis whereas those starting or finishing with exons 46 or 52 (11/11) were not. Formal IQ assessments (verbal, performance, and full scores) were available for 47 patients. Mean IQ score among the DMD patients was 83 and no clear relationship was found between gene mutations and IQ. The mutations in patients with a particularly severe deficit of verbal IQ were spread throughout the gene.

Adolescent↗
PubMed1993

Integrated study of 100 patients with Xp21 linked muscular dystrophy using clinical, genetic, immunochemical, and histopathological data. Part 3. Differential diagnosis and prognosis.

This report is the third part of a trilogy from a multidisciplinary study which was undertaken to investigate gene and protein expression in a large cohort of patients with well defined and diverse clinical phenotypes. The aim of part 3 was to review which of the analytical techniques that we had used would be the most useful for differential diagnosis, and which would provide the most accurate indication of disease severity. Careful clinical appraisal is very important and every DMD patient was correctly diagnosed on this basis. In contrast, half of the sporadic BMD patients and all of the sporadic female patients had received different tentative diagnoses based on clinical assessments alone. Sequential observations of quantitative parameters (such as the time taken to run a fixed distance) were found to be useful clinical indicators for prognosis. Intellectual problems might modify the impression of physical ability in patients presenting at a young age. Histopathological assessment was accurate for DMD but differentiation between BMD and other disorders was more difficult, as was the identification of manifesting carriers. Our data on a small number of women with symptoms of muscle disease indicate that abnormal patterns of dystrophin labelling on sections may be an effective way of differentiating between female patients with a form of limb girdle dystrophy and those carrying a defective Xp21 gene. Dystrophin gene analysis detects deletions/duplications in 50 to 90% of male patients and is the most effective non-invasive technique for diagnosis. Quantitative Western blotting, however, would differentiate between all Xp21 and non-Xp21 male patients. In this study we found a clear relationship between increased dystrophin abundance (determined by densitometric analysis of blots) and clinical condition, with a correlation between dystrophin abundance and the age at loss of independent mobility among boys with DMD and intermediate D/BMD. This indicates that blotting is the most sensitive and accurate technique for diagnosis and prognosis.

Adolescent↗
PubMed1992

Familial paroxysmal rhabdomyolysis: management of two cases of the non-exertional type.

Familial paroxysmal rhabdomyolysis with myoglobinuria is a rare and life-threatening disease of young children, of unknown aetiology. Attacks bear no relation to exercise, are usually triggered by intercurrent infections and are often severe. The authors describe two cases and suggest plans for the prevention and management of attacks. Fasting appears to be the crucial factor precipitating attacks, but is not associated with hypoglycaemia or with a defect in lactate production, ketogenesis or fatty acid mobilisation. The fatty acid-binding protein in a muscle biopsy from one case was normal.

Biopsy↗
PubMed1992

Combined enzyme defect of mitochondrial fatty acid oxidation.

A young girl presented with recurrent episodes of muscle weakness culminating in a severe attack of generalized muscle weakness. In the muscle mitochondria from the patient there was an abnormal pattern of intermediates of beta-oxidation with an accumulation of 3-hydroxyacyl- and 2-enoyl-CoA and carnitine esters, and 3-oxoacylcarnitines. There was low activity of long-chain 3-hydroxyacyl-CoA dehydrogenase in mitochondria from all tissues. The activity of long-chain 2-enoyl-CoA hydratase was low in muscle mitochondria and 3-oxoacyl-CoA thiolase activity measured with 3-oxohexadecanoyl-CoA as substrate was low in fibroblast, muscle, and cardiac mitochondria but only partial deficiency was present when the activity was measured with 3-oxooctanoyl-CoA. The activity of the long-chain 3-hydroxyacyl-CoA dehydrogenase and long-chain 3-oxoacyl-CoA thiolase in fibroblasts from the patient's parents was intermediate between those of controls and the patient. The patient has a combined defect of the long-chain 3-hydroxyacyl-CoA dehydrogenase, long-chain 3-oxoacyl-CoA thiolase, and long-chain 2-enoyl-CoA hydratase which appears to be inherited in an autosomal recessive manner. This suggests there is a multifunctional enzyme catalyzing these activities in human mitochondria and that this enzyme is deficient in our patient.

3-Hydroxyacyl CoA Dehydrogenases↗
PubMed1991

Prevalence and incidence of Becker muscular dystrophy.

We measured the prevalence and incidence of Becker muscular dystrophy in the Northern Health Region of England, UK. Patients were identified from the records of the Regional Neurological Centre and Muscular Dystrophy Group laboratories, Newcastle upon Tyne, and by writing to local doctors. We used cDNA probes and/or dystrophin immunolabelling of muscle-biopsy samples to prove the diagnosis of all cases. Results were compared with the known prevalence and incidence of Duchenne muscular dystrophy. 73 patients alive and resident in the Northern Health Region were identified, giving a prevalence rate of 2.38/100,000. This compares with a prevalence of Duchenne muscular dystrophy of 2.48/100,000. The cumulative birth incidence of Becker muscular dystrophy (at least 1 in 18 450 male live births) was about one third that of Duchenne muscular dystrophy (1 in 5618 male live births), suggesting that the disorder is more common than previously thought.

Adolescent↗
PubMed1991

Encephalitis lethargica-like illness in a five-year-old.

A five-year-old boy presented with an encephalitis lethargica-like illness, characterised by somnolence, mutism and Parkinsonian rigidity two weeks after an acute exanthem. Investigation revealed increased serum measles antibody titre. He made a complete recovery. Encephalitis lethargica associated with Parkinsonism in childhood is rare and usually carries a poor prognosis.

Akinetic Mutism↗
PubMed1991

Head circumference and intellectual performance of patients with Duchenne muscular dystrophy.

The head circumferences of 64 patients with Duchenne muscular dystrophy were measured and found to be greater than those of a normal population. The patients had relative, and in 12 cases, absolute macrocephaly. 47 of the 64 patients underwent intelligence testing and were found to be significantly intellectually impaired, particularly in verbal and language skills. There was no correlation between head circumference or absolute macrocephaly and intellectual performance. The cause of macrocephaly in these patients is unknown and its relevance to the aetiology of intellectual impairment in Duchenne muscular dystrophy is not yet clear.

Adolescent↗