ABSTRACT
BACKGROUND: Mitochondrial DNA (mtDNA) mutations are increasingly being recognized as causes of late-onset disease. We report a patient with a late-onset mitochondrial encephalomyopathy caused by a novel G > C transition in mtDNA at position 5556 in the gene encoding the tRNA for tryptophan (MTTW). AIMS: To investigate the cause of disease and assess the pathogenicity of this new mutation. METHODS: Clinical, histopathological and gene sequencing studies. Quantification of the mutation was performed in different tissues from the patient and two relatives and in single muscle fibres. RESULTS: The mutation was heteroplasmic, segregated in biochemically affected muscle fibres and was absent in blood. The level of mutation in skeletal muscle was higher than in brain, although the brain was clinically the most affected tissue. DISCUSSION: The 5556G > C mutation appears sporadic. It was not found in any of the family members tested, although some of them manifested disorders that can be associated with mtDNA disease. In addition to reporting the eighth mutation in MTTW, our case illustrates the challenges posed when assigning pathogenicity to mtDNA mutations.
Subject(s)
DNA, Mitochondrial/genetics , Mitochondrial Encephalomyopathies/genetics , Point Mutation , RNA, Transfer, Trp/genetics , Age of Onset , Aged , Base Sequence , Brain/metabolism , DNA, Mitochondrial/chemistry , Female , Humans , Male , Middle Aged , Mitochondrial Encephalomyopathies/blood , Mitochondrial Encephalomyopathies/metabolism , Muscle, Skeletal/metabolism , Nucleic Acid Conformation , Pedigree , RNA, Transfer, Trp/metabolism , Sequence Analysis, DNA , SiblingsABSTRACT
Patients with paraneoplastic encephalomyelitis(subacute sensory neuronopathy) (PEM/SSN), most commonly associated with small-cell lung cancer (SCLC), frequently harbor Hu antibodies, which are usually detected by indirect immunohistochemistry or immunoblot. We developed a new radioimmunobinding assay to detect Hu antibodies based on in vitro transcribed and translated (ITT) HuD. High levels of Hu antibodies were detected in all seven PEM/SSN patients tested, but not in any of 15 patients with other paraneoplastic syndromes, 20 patients with Sjögren's syndrome, 20 patients with miscellaneous tumors and 99 of 100 blood donors. One of the blood donors had low levels of Hu antibodies. The radiobinding assay detected Hu antibodies in 45 of 191 (24%) patients with SCLC, in comparison with immunofluorescence and immuno dot blot, where only 34 of 191 (18%) were detected. All patients with Hu antibodies detected by immunofluorescence and immuno dot-blot were also positive by the radioimmunobinding assay. The results demonstrate that this assay is very specific and sensitive for the detection of Hu antibodies.
Subject(s)
Antibodies/blood , Antibodies/immunology , Nerve Tissue Proteins/immunology , Paraneoplastic Syndromes, Nervous System/blood , Paraneoplastic Syndromes, Nervous System/immunology , RNA-Binding Proteins/immunology , Radioimmunoassay/methods , ELAV Proteins , ELAV-Like Protein 4 , Female , Fluorescent Antibody Technique/standards , Humans , Immunoblotting/standards , Male , Neurons, Afferent/immunology , Neurons, Afferent/pathology , Paraneoplastic Syndromes, Nervous System/diagnosis , Peripheral Nervous System Diseases/blood , Peripheral Nervous System Diseases/diagnosis , Peripheral Nervous System Diseases/immunology , Predictive Value of Tests , Reference Values , Reproducibility of Results , Sjogren's Syndrome/blood , Sjogren's Syndrome/diagnosis , Sjogren's Syndrome/immunologyABSTRACT
The aim of this study was to determine the nucleotide sequence of the third variable (V3) domain of HIV-1 gp120 from strains circulating in the Kilimanjaro region of Tanzania. DNA from this region was amplified from patient peripheral blood lymphocytes using polymerase chain reaction and then subjected to automated DNA sequencing. Subtype A, B, C, and D-like sequences were identified. Subtype B has not previously been described in Tanzania.
