1/5. OXPHOS and mtDNA alterations in a family with spastic paraparesis.OBJECTIVE: To study muscle biopsies in hereditary spastic paraparesis (HSP). methods: We analyzed oxidative phosphorylation activities and mtDNA in 3 individuals from an HSP family. RESULTS: We found histochemical evidence for mitochondrial proliferation and cytochrome c oxidase negative fibers. Biochemically, there was an important reduction of the activities of complexes I and IV in 3 patients. In addition, multiple mtDNA deletions (ranging 4.0-7.0 kb) were found in 2 cases by PCR but not by Southern blot. CONCLUSION: We suggest the use of a muscle biopsy when examining HSP patients. HSP can represent a disorder of nuclear-mitochondrial intercommunication.- - - - - - - - - - ranking = 1keywords = complex (Clic here for more details about this article) |
2/5. A novel frameshift mutation of the mtDNA COIII gene leads to impaired assembly of cytochrome c oxidase in a patient affected by Leigh-like syndrome.We report on a novel frameshift mutation in the mtDNA gene encoding cytochrome c oxidase (COX) subunit III. The proband is an 11-year-old girl with a negative family history and an apparently healthy younger brother. Since 4 years of age, she has developed a progressive spastic paraparesis associated with ophthalmoparesis and moderate mental retardation. The presence of severe lactic acidosis and Leigh-like lesions of putamina prompted us to perform muscle and skin biopsies. In both, a profound, isolated defect of COX was found by histochemical and biochemical assays. sequence analysis of muscle mtDNA resulted in the identification of a virtually homoplasmic frameshift mutation in the COIII gene, due to the insertion of an extra C at nucleotide position 9537 of mtDNA. Although the 9537C(ins) does not impair transcription of COIII, no full-length COX III protein was detected in mtDNA translation assays in vivo. Western blot analysis of two-dimensional blue-native electrophoresis showed a reduction of specific crossreacting material and the accumulation of early-assembly intermediates of COX, whereas the fully assembled complex was absent. One of these intermediates had an electrophoretic mobility different from those seen in controls, suggesting the presence of a qualitative abnormality of COX assembly. Immunostaining with specific antibodies failed to detect the presence of several smaller subunits in the complex lacking COX III, in spite of the demonstration that these subunits were present in the crude mitochondrial fraction of patient's cultured fibroblasts. Taken together, the data indicate a role for COX III in the incorporation and maintenance of smaller COX subunits within the complex.- - - - - - - - - - ranking = 3keywords = complex (Clic here for more details about this article) |
3/5. A large family with hereditary spastic paraparesis due to a frame shift mutation of the spastin (SPG4) gene: association with multiple sclerosis in two affected siblings and epilepsy in other affected family members.Hereditary spastic paraparesis (HSP) is a clinically and genetically heterogeneous neurodegenerative disorder characterised by progressive lower limb spasticity and weakness. Some forms have been associated with white matter lesions and complex phenotypes. This study was prompted by the diagnosis of multiple sclerosis (MS) in two sisters from a large pedigree with hereditary spastic paraparesis. Twelve affected members of the extended family were examined (MRI and EEG were carried out and evoked potentials measured in five), and historical information was obtained from six affected deceased persons. The inherited disease phenotype was confirmed as autosomal dominant hereditary spastic paraparesis associated with epilepsy in four affected persons. None of the extended family had evidence of MS. Genetic analysis of the family has shown linkage to chromosome 2p and sequencing of the spastin gene has identified a 1406delT frameshift mutation in exon 10. This kindred demonstrates the clinical heterogeneity of HSP associated with spastin mutations. The possible relevance of the concurrence of HSP and MS in the sib pair is discussed.- - - - - - - - - - ranking = 1keywords = complex (Clic here for more details about this article) |
4/5. Novel heteroplasmic mtDNA mutation in a family with heterogeneous clinical presentations.The protean manifestations of a novel maternally inherited point mutation of the mitochondrial genome are reported. The proband showed isolated, spastic paraparesis. A brother, who had suffered from a multisystem progressive disorder, ultimately died of cardiomyopathy. Another brother is healthy. The proband's mother showed truncal ataxia, dysarthria, severe hearing loss, mental regression, ptosis, ophthalmoparesis, distal cyclones, and diabetes mellitus. A muscle biopsy performed in the proband failed to show the morphological abnormalities typical of mitochondrial disorders; the activities of respiratory chain complexes were normal. However, complex I and IV activities were low in the muscle homogenate of the affected mother and brother. sequence analysis of mtDNA showed a heteroplasmic mutation of the tRNA(Ile) gene (G4284A). The mutation load was approximately 55%, 80%, and 90% in the muscle mtDNA of the proband, his mother, and his affected brother, respectively. Mutation was undetected in the healthy brother, as well as in 100 control samples. Several cybrid clones containing homoplasmic mutant mtDNA from the proband showed significant reductions of complex IV activity and maximum oxygen consumption rate, compared with homoplasmic wild-type clones derived from the same subject.- - - - - - - - - - ranking = 3keywords = complex (Clic here for more details about this article) |
5/5. Adrenomyeloneuropathy as a cause of primary adrenal insufficiency and spastic paraparesis.Adrenomyeloneuropathy is a varient of adrenoleukodystrophy, both of which are rare inherited disorders of peroxisomes characterized by the accumulation of very-long-chain fatty acids in plasma, the central and peripheral nervous systems, adrenal glands and testes, which leads to dysfunction of these organs and systems. In this article, we describe an illustrative case of adrenomyeloneuropathy and discuss the clinical presentation, diagnosis and management of the 2 disorders.- - - - - - - - - - ranking = 137652.92525829keywords = adrenomyeloneuropathy (Clic here for more details about this article) |