Chronic Leigh Disease: a genetic and biochemical study

The large family of a 21-year-old man who died of Leigh disease was investigated for evidence of neurological abnormalities and presence of the adenosine triphosphate-thiamine diphosphate phosphoryltransferase inhibitor factor. Of 217 persons (seven generations) included in the pedigree, 68 were examined neurologically and biochemically. Fourteen (20%), 5 of whom had abnormal neurological findings, were found to excrete the inhibitor factor. Clinical manifestations varied from severe neurological affliction to subtle deficits. A chronic relapsing course was frequently encountered, with exacerbations occurring in association with apparent metabolic stress. Parental consanguinity was identified in the propositus as well as in other family members with neurological abnormalities. Males and females were affected, and no vertical transmission of the trait was found. These multigenerational data suggest that Leigh disease in adults is inherited in an autosomal recessive manner and has variable degrees of expression with a wide spectrum of neurological manifestations.     

Leigh syndrome: Clinical features and biochemical and DNA abnormalities

We investigated the etiology of Leigh syndrome in 67 Australian cases from 56 pedigrees, 35 with a firm diagnosis and 32 with some atypical features. Biochemical or DNA defects were determined in both groups, ie, 80% in the tightly defined group and 41% in the “Leigh-like” group. Eleven patients had mitochondrial DNA point mutations (nucleotide [nt] 8993 T to G, nt 8993 T to C, or nt 8344 A to G) and 1 Leigh-like patient had a heteroplasmic deletion. Twenty-nine patients had enzyme defects, ie, 13 respiratory chain complex I, 9 complex IV, and 7 pyruvate dehydrogenase complex (PDHC). Complex I deficiency is more common than recognized previously. Six PDHC-deficient patients had mutations in the X-chromosomal gene encoding the Elα subunit of PDHC. Parental consanguinity suggested autosomal recessive inheritance in two complex IV-deficient sibships. We found no strong correlation between the clinical features and basic defects. An assumption of autosomal recessive inheritance (frequently made in the past) would have been wrong in nearly one-half (1 1 of 28 tightly defined and 18 of 41 total patients) of those in whom a cause was found. A specific defect must be identified if reliable genetic counseling is to be provided.     

Case of methylmalonic acidemia presenting clinically Leigh encephalopathy

A 1-year-old boy with methylmalonic acidemia had symmetrical lesions of the bilateral basal ganglia, which suggested Leigh encephalopathy. The findings on brain magnetic resonance imaging (MRI) and his physical condition greatly improved by the intravenous administration of vitamin B1. We hypothesized that in this case, clinical Leigh encephalopathy was caused by a impairment of the activity of pyruvate carboxylase induced by the accumulation of methylmalonyl CoA and an impairment of energy production due to a lack of vitamin B1, especially impairment of the activity of pyruvate dehydrogenase complex during an acute worsening of methylmalonic acidemia. Thus, in the treatment of methylmalonic acidemia, attention should be paid to vitamin B1 deficiency. During an acute worsening, vitamin B1 should be administered by intravenous drip injection.     

Ethylmalonic encephalopathy: clinical and biochemical observations

Ethylmalonic encephalopathy (EE) is a rare, recently defined inborn error of metabolism which affects the brain, gastrointestinal system and peripheral blood vessels and is characterized by a unique constellation of clinical and biochemical features. A 7-month-old male, who presented with psychomotor retardation, chronic diarrhea and relapsing petechiae is described with the objective of highlighting the biochemical and neuroradiological features of this disorder as well as the effect of high-dose riboflavin therapy. Urinary organic acid analysis revealed markedly increased excretion of ethylmalonic acid, isobutyrylglycine, 2-methylbutyrylglycine and isovalerylglycine. Acylcarnitine analysis in dried blood spots showed increased butyrylcarnitine. Short-chain acyl-CoA dehydrogenase (SCAD) activity in muscle was normal as were mitochondrial OXPHOS enzyme activities in cultured skin fibroblasts. In skeletal muscle the catalytic activity of complex II was decreased. Brain MRI revealed bilateral and symmetrical atrophy in the fronto-temporal areas, massive enlargement of the subarachnoid spaces and hyperdensities on T (2) sequences of the basal ganglia. Mutation analysis of the ETHE1 gene demonstrated homozygosity for the Arg163Gly mutation, confirming the diagnosis of EE at a molecular level. On repeat MRI, a significant deterioration was seen, correlating well with the clinical deterioration of the patient.     

Genetic and biochemical findings in Chinese children with Leigh syndrome

This study investigated the genetic and enzymological features of Leigh syndrome due to respiratory chain complex deficiency in Chinese patients. The clinical features of 75 patients were recorded. Mitochondrial respiratory chain enzyme activities were determined via spectrophotometry. Mitochondrial gene sequence analysis was performed in 23 patients. Five core pedigrees were investigated via restriction fragment length polymorphism and gene sequencing. Psychomotor retardation (55%), motor regression (20%), weakness (29%), and epilepsy (25%) were the most frequent manifestations. Sixty-four patients (85.3%) had isolated respiratory complex deficiencies: complex I was seen in 28 patients (37.3%); complex II, seven (9.3%); complex III, six (8%); complex IV, ten (13.3%); and complex V, 13 patients (17.3%). Eleven patients (14.7%) had combined complex deficiencies. Mitochondrial DNA mutations were detected in 10 patients. Eight point mutations were found in mitochondrial structural genes: m.4833A > G in ND2, m.10191T > C in ND3, m.12338T > C and m.13513G > A in ND5, m.14502T > C and m.14487T > C in ND6, m.8108A > G in COXII, and m.8993T > G in ATPase6. Three mutations were found in tRNA genes: m.4395A > G in tRNA-Gln, m.10454T > C in tRNA-Arg, and m.5587T > C in tRNA-Ala. One patient and their mother both had the m.12338T > C and m.8993T > C mutations. In conclusion, mitochondrial respiratory chain complex I deficiency and structural gene mutations frequently occur in Chinese Leigh syndrome patients.     

Immunochemical and biochemical analyses of myosin light chains from normal and denervated cardiac muscle

Rabbit antisera were prepared against the combined low molecular weight subunits (the light chains) of canine cardiac myosin. The antisera reacted specifically with the light chains and with purified myosin. There were no immunochemical reactions with the heavy myosin chains. The antisera were then used to test preparations of light chains isolated from hearts maintained in a denervated condition for 12, 4, or 2 weeks prior to killing the animals. Denervation was accomplished by mediastinal neural ablation. The light chains prepared from the denervated hearts all reacted with the antisera and showed immunological identity with the light chains from control muscle. The specific adenosine triphosphatase activity of myosin prepared from hearts denervated for 12, 4, or 2 weeks exhibited a marked deviation from control activity. We concluded that, although cardiac denervation did not affect the immunological properties of myosin light chains, the biological activity of cardiac myosin was greatly reduced after 2 weeks of denervation and recovered somewhat after 4 weeks.     

The cortical form of subacute necrotizing encephalopathy of the Leigh type. A light- and electron-microscopic study.

The present paper is a clinico-pathological study of a 14-year-old boy with a chronic, progressive occipital syndrome for which he was operated upon. Postoperatively, metabolic acidosis developed. Pathological anatomy revealed spongy necrosis of the thalamus and corpora quadrigemina with the typical histological features of Leigh's necrotizing encephalopathy. Similar necrotic lesions had developed in the occipital cortex. At this level apart from the typical foci, cavitating necrosis was found as well as involvement of the smaller vessels of the pial circulation. Electron microscopy revealed vascular and glial changes suggestive of primary mesenchymoglial dystrophy. The histiocytes presented intracytoplasmic multiplication of lysosomes and their transformation into lipofuscin pigment. The changes demonstrate a juvenile cortical form of Leigh's subacute necrotizing encephalopathy.     

Significance of muscle biopsies in neuronal ceroid-lipofuscinoses.

Muscle specimens obtained at necropsy from four cases of neuronal ceroid-lipofuscinosis (NCL), three of the juvenile and one of the late infantile type, and a muscle biopsy from a fifth patient with the juvenile type of NCL, all showed curvilinear bodies typical of NCL within the muscle fibres. The pigments were autofluorescent. It appears that skeletal muscle is a reliable tissue source for the diagnosis of these disorders by biopsy.     

Diagnosis and treatment in a case of juvenile subacute necrotizing encephalopathy Leigh without cytochrome c oxidase deficiency.

Subacute necrotizing encephalopathy (Leigh syndrome) is characterized by lactacidosis, seizures, ataxia, multiple cerebral hypervascularized lesions and mitochondrial oxidation defects. This is a report on a 21-year-old patient with proven Leigh syndrome, mild central and provokable peripheral lactacidosis, an extra-erythrocyte complex II defect, functionally reduced myokinase adenylate deaminase activity, but no ultrastructural mitochondrial changes. Determination of lactate, pyruvate and ammonia under ischemic conditions plus a pyruvate loading test were particularly useful. Oral flunarizine (Sibelium 30 mg/d) proved to be therapeutically effective.     

Mitochondrial DNA T to G mutation 8993 in Leigh encephalopathy and organic aciduria

We report a 10-month-old female infant with Leigh encephalopathy caused by a T to G mutation at nucleotide 8993 of mitochondrial DNA. Initial manifestations were diarrhea and pyrexia, followed by disturbance of consciousness. Blood chemistry showed lactic acidosis, and cranial T2 weighted magnetic resonance imaging demonstrated symmetric high-intensity areas in the basal ganglia, consistent with Leigh encephalopathy. Analysis of urinary organic acids revealed a increase of alpha-ketoglutamate. Derivatives of branched chain amino acids, which accumulate in maple syrup disease, were also increased. Lipoamide dehydrogenase (E3) deficiency was initially suspected; however, normal activity of pyruvate dehydrogenase complex excluded the diagnosis. The organic aciduria disappeared after two weeks. The CNS lesions in our case were observed more prominently in the floor of the bilateral frontal lobes than in the globus pallidus and putamen. In this case, mitochondrial DNA mutation may have caused organic aciduria and the atypical imaging findings.     

Characteristic changes on brain CT in a case of Leigh encephalopathy with deficiency of pyruvate dehydrogenase.

A girl aged 23 months of Leigh encephalopathy with pyruvate dehydrogenase complex (PDHC) deficiency was reported. Brain CT scan showed atrophy of the frontal and parietal cortex, low density in the midbrain and putamina, and rounded caudatum. CT change was showed from rounded to atrophic caudatum during a three-month period. The rounded caudatum may be an early CT finding in Leigh encephalopathy.     

Comparison of the muscle fiber diameter and satellite cell frequency in human muscle biopsies.

Satellite cells are responsible for the formation of postnatal muscle fibers. The number, mitotic activity, and differentiation potential of satellite cells and the muscle fiber diameter are tightly regulated events in normal muscle. The signal that induces satellite cells to stop proliferation once the determined muscle fiber size has been reached in normal growth is not known. The aim of the present study was to determine whether a correlation exists between satellite cell frequency and muscle fiber diameter in human muscle disease. Muscle biopsies from 7 cases of Duchenne muscular dystrophy (DMD), 8 other muscular dystrophies, 23 cases of inflammatory myopathy, and 22 cases of neurogenic atrophy were examined. The satellite cell number was elevated in DMD and neurogenic atrophy but not in other muscular dystrophies or inflammatory myopathies. Nevertheless, in all the diseased muscles, but not in normal controls, there was a significantly higher relative frequency of satellite cells with increasing fiber diameter. It has been shown before that satellite cells show ultrastructural and autoradiographic signs of activation and proliferation in myopathic and neurogenic conditions. We assume that we are dealing with activated, not quiescent, satellite cells in diseased muscle and that under these conditions the fiber diameter does not represent a stop signal for satellite cells to proliferate. The data suggest that not only the number of satellite cells matters in diseased muscle, as has been shown before, but that it is their behavior that influences, at least in part, progress and severity of muscle diseases.     

Lesions of the tunica media in traumatic rupture of vertebral arteries: histologic and biochemical studies.

Discontinuous non-circumferential lesions of tunica media were observed in four cases of traumatic rupture of the vertebral artery. We hypothesize that these lesions were due to mechanical disruption of smooth muscle cells and the liberation of catabolic enzymes with subsequent degradation of the arterial media. To test this hypothesis, healthy vertebral arteries were incubated with crude extracts of bovine smooth muscle cytosol in attempt to reproduce the histological changes of the arterial media in traumatized vertebral arteries. We observed cytosol-induced degradation of tunica media, characterized by pallor of staining with the Masson's Trichrome method, which was due to catabolic enzyme activity that was effectively inhibited by heat inactivation of the cytosol. The cytosol-induced tinctorial changes were similar to the lesions of the tunica media in naturally-occurring cases of traumatic vertebral artery rupture. We conclude that although vertebral arteries can be ruptured by physical distortion alone, associated lesions of the tunica media are due to in situ trauma-associated release of heat-labile catabolic enzymes.     

Morphological and biochemical findings in jejunal biopsies from patients with multiple sclerosis.

Gluten withdrawal from the diet is occasionally used speculatively in the management of multiple sclerosis. To assess whether there might be any rational basis for such a measure we have undertaken morphological and biochemical studies of the jejunal mucosa in 14 patients with multiple sclerosis. All were found to have morphologically normal villi, and quantitative estimation of surface-to-volume ratios gave values which did not differ from control subjects. Intraepithelial lymphocyte counts were normal. Antigliadin antibody titres were not raised in any patient. Estimation of activity of the brush border disaccharidases (sucrase, lactase, and maltase (showed that the mean level of each enzyme did not differ significantly from control subjects. Analytical subcellular fractionation of the biopsies showed no changes in the distribution or activity of marker enzymes for the brush order, lysosomes, mitochondria, cytosol, peroxisomes, or endoplasmic reticulum. It is concluded that there are no gross morphological or biochemical abnormalities in the jejunal mucosa in patients with multiple sclerosis and, therefore, that the use of gluten-free diets cannot be justified on the assumption that these patients suffer from a coeliac-like lesion of the small intestine.     

Adult onset scapuloperoneal myopathy: diagnostic value of nerve morphometry and multiple muscle biopsies.

In the scapuloperoneal syndrome, differentiation between neurogenic and myopathic processes may be difficult despite electromyography and muscle biopsy. Extensive analysis, including morphometry, was conducted on multiple nerve and muscle biopsies from two adult onset, sporadic cases with the syndrome. These studies confirm a myopathic process and further define the entity of adult onset scapuloperoneal myopathy.     

Ultrastructural lesions of muscle and immunofluorescent deposits in vessels in Reye's syndrome: a preliminary report of serial muscle biopsies.

Thirteen sequential percutaneous skeletal muscle biopsy specimens from 4 patients with Reye's syndrome were studied ultrastructurally and by direct immunofluorescence. Prominent generalized intermyofibrillar edema, mitochondrial disruption, and swelling of vascular endothelium were demonstrated in 2 patients. In all 4 patients there were granular deposits of immunoglobulins G and M in intramuscular vessels, presumably representing antigen-antibody complexes. We postulate that these changes may be pathogenetically important in this syndrome and suggest that muscle biopsy tissue be utilized for further investigation of Reye's syndrome.