Previous fibroblast and recombinant enzyme studies showed a markedly thermolabile p.Ser113Leu variant compared to the wild-type (WT) in muscle carnitine palmitoyltransferase II (CPT II) deficiency. Additionally, it has been shown that cardiolipin (CLP) stimulated or inhibited the p.
View Article and Find Full Text PDFThe Kennedy pathways catalyse the de novo synthesis of phosphatidylcholine and phosphatidylethanolamine, the most abundant components of eukaryotic cell membranes. In recent years, these pathways have moved into clinical focus because four of ten genes involved have been associated with a range of autosomal recessive rare diseases such as a neurodevelopmental disorder with muscular dystrophy (CHKB), bone abnormalities and cone-rod dystrophy (PCYT1A) and spastic paraplegia (PCYT2, SELENOI). We identified six individuals from five families with bi-allelic variants in CHKA presenting with severe global developmental delay, epilepsy, movement disorders and microcephaly.
View Article and Find Full Text PDFMitochondrial processes may play a role in the pathophysiology of migraine. Serum levels of two biomarkers, Fibroblast-growth-factor 21 (FGF-21) and Growth-differentiation-factor 15 (GDF-15), are typically elevated in patients with mitochondrial disorders. The study investigated whether the presence of migraine may influence FGF-21 and GDF-15 serum levels considering vascular and metabolic disorders as possible confounders.
View Article and Find Full Text PDFMuscle carnitine palmitoyltransferase II (CPT II) deficiency is associated with various mutations in gene. In the present study, the impact of the two CPT II variants P50H and Y479F were characterized in terms of stability and activity in vitro in comparison to wildtype (WT) and the well investigated variant S113L. While the initial enzyme activity of all variants showed wild-type-like behavior, the activity half-lives of the variants at different temperatures were severely reduced.
View Article and Find Full Text PDFIt is known that exposure to excess saturated fatty acids, especially palmitate, can trigger cellular stress responses interpreted as lipotoxicity. The effect of excessive free fatty acids on oxidative phosphorylation capacity in myoblasts of patients with the m.3243A>G mutation was evaluated with the mitochondrial (Mito) stress test using a Seahorse XF96 analyzer.
View Article and Find Full Text PDFMitochondrial function is essential for ATP-supply, especially in response to different cellular stressors. Increased mitochondrial biogenesis resulting from caloric restriction (CR) has been reported. Resveratrol (RSV) is believed to mimic the physiological effects of CR mainly via a sirtuin (SIRT) 1-dependent pathway.
View Article and Find Full Text PDFPathogenic variants in the are a well-known cause for maternally inherited mitochondrial disorders associated with a wide range of clinical phenotypes. Here, we present a 31- year old female with insulin-dependent diabetes mellitus, recurrent lactic acidosis and ketoacidosis recurrent infections with suspected immunodeficiency with T cell lymphopenia and hypogammaglobulinemia as well as proximal tetraparesis with severe muscle and limb pain and rapid physical exhaustion. Muscle biopsy and respiratory chain activities were normal.
View Article and Find Full Text PDFBackground: In patients with neuromuscular disorder, only little data of myalgia frequency and characterization exists. To date, only a weak correlation between pain intensity and pressure pain threshold has been found, and it remains enigmatic whether high pain intensity levels are equivalent to high pain sensitivity levels in neuromuscular disorders.
Methods: 30 sequential patients with suspected neuromuscular disorder and myalgia were analyzed with regard to myalgia characteristics and clinical findings, including symptoms of depression and anxiety and pain- threshold.
Different mitochondrial DNA (mtDNA) mutations have been identified to cause mitochondrial encephalopathy, lactate acidosis and stroke-like episodes (MELAS). The underlying genetic cause leading to an enormous clinical heterogeneity associated with m.3243A>G-related mitochondrial diseases is still poorly understood.
View Article and Find Full Text PDFMitochondrial dysfunction is known to play a key role in the pathophysiological pathway of neurodegenerative disorders. Nuclear-encoded proteins are involved in mtDNA replication, including DNA polymerase gamma, which is the only known replicative mtDNA polymerase, encoded by nuclear genes Polymerase gamma 1 (POLG) and Polymerase gamma 2 (POLG2). mutations are well-known as a frequent cause of mitochondrial myopathies of nuclear origin.
View Article and Find Full Text PDFFibroblast growth factor 21 (FGF-21) is known to be a biomarker for mitochondrial disorders. An upregulation of FGF-21 in serum and muscle of carnitine palmitoyltransferase I (CPT I) and carnitine palmitoyltransferase II (CPT II) knock-out mice has been reported. In human CPT II deficiency, enzyme activity and protein content are normal, but the enzyme is abnormally regulated by malonyl-CoA and is abnormally thermolabile.
View Article and Find Full Text PDFThe phospholipid environment of the mitochondrial inner membrane, which contains large amounts of cardiolipin, could play a key role in transport of the long chain fatty acids. In the present study, the pre-incubation of cardiolipin with the wild type carnitine palmitoyltransferase (CPT) II led to a more than 1.5-fold increase of enzyme activity at physiological temperatures.
View Article and Find Full Text PDFThe diagnosis of mitochondrial diseases is still challenging due to clinical and genetical heterogeneity. The development of advanced technologies including Whole-Exome- Sequencing (WES) and Whole-Genome-Sequencing (WGS) has led to improvements in genetic diagnosis. However, a reliable biomarker in serum could enhance and ease the diagnosis and indeed reduce the need for muscle biopsy.
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