Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C1762617 (weakness)
 37,932 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Disorders of glycogen, lipid or mitochondrial metabolism may cause two main clinical syndromes, namely (1) progressive weakness (eg, acid maltase, debrancher enzyme, and brancher enzyme deficiencies among the glycogenoses; long- and very-long-chain acyl-CoA dehydrogenase (LCAD, VLCAD), and trifunctional enzyme deficiencies among the fatty acid oxidation (FAO) defects; and mitochondrial enzyme deficiencies) or (2) acute, recurrent, reversible muscle dysfunction with exercise intolerance and acute muscle breakdown or myoglobinuria (with or without cramps) (eg, phosphorylase (PPL), phosphorylase b kinase (PBK), phosphofructokinase (PFK), phosphoglycerate kinase (PGK), phosphoglycerate mutase (PGAM), and lactate dehydrogenase (LDH) among the glycogenoses and carnitine palmitoyltransferase II (CPT II) deficiency among the disorders of FAO or (3) both (eg, PPL, PBK, PFK among the glycogenoses; LCAD, VLCAD, short-chain L-3-hydroxyacyl-CoA dehydrogenase (SCHAD), and trifunctional enzyme deficiencies among the FAO defects; and multiple mitochondrial DNA (mtDNA) deletions). Myoadenylate deaminase deficiency, a purine nucleotide cycle defect, is somewhat controversial and is characterized by exercise-related cramps leading rarely to myoglobinuria.
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PMID:Metabolic myopathies. 879 43

In hospitalized patients rhabdomyolysis is an important clinical entity, leading to myoglobinuria and acute renal failure in 8-25% of cases. When common causes of rhabdomyolysis, such as crush, trauma, infections, and drug abuse are excluded, inherited disorders of energy metabolism, in particular lipid metabolism, should be considered. Carnitine palmitoyltransferase (CPT) II deficiency is a common disorder of mitochondrial lipid oxidation. There are two distinct clinical forms: a severe and usually fatal infantile form and a benign classical muscular form. Usually, patients with CPT II deficiency present with episodic myoglobinuria, muscle cramps and weakness prompted by strenuous exercise or prolonged fasting. Liver and cardiac dysfunction are rarely seen and indicate severe disease. Most affected patients are males, although CPT II deficiency shows an autosomal recessive mode of inheritance. The human CPT II gene has been cloned, sequenced and localised to chromosome 1p32. Several mutations have been detected in the human gene which differ in the remaining enzyme activity and may explain the heterogeneity in the clinical picture of this disorder. Diagnosis is by muscle biopsy. Normally, light microscopy shows no pathological findings, and diagnosis must be established by biochemical and molecular methods. In our report on two typical cases we set out to promote knowledge of this disorder and discuss the diagnostic approach, which requires a specialised laboratory.
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PMID:[Rhabdomyolysis in carnitine palmitoyltransferase II deficiency: developments in pathophysiology, diagnosis and therapy]. 969 38

The primary presentations of neuromuscular disease in the newborn period are hypotonia and weakness. Although metabolic myopathies are inherited disorders that present from birth and may present with subtle to marked neonatal hypotonia, a number of these defects are diagnosed classically in childhood, adolescence, or adulthood. Disorders of glycogen, lipid, or mitochondrial metabolism may cause three main clinical syndromes in muscle, namely, (1) progressive weakness with hypotonia (e.g., acid maltase, debrancher enzyme, and brancher enzyme deficiencies among the glycogenoses; carnitine uptake and carnitine acylcarnitine translocase defects among the fatty acid oxidation (FAO) defects; and cytochrome oxidase deficiency among the mitochondrial disorders) or (2) acute, recurrent, reversible muscle dysfunction with exercise intolerance and acute muscle breakdown or myoglobinuria (with or without cramps), e.g., phosphorylase, phosphofructokinase, and phosphoglycerate kinase among the glycogenoses and carnitine palmitoyltransferase II deficiency among the disorders of FAO or (3) both (e.g., long-chain or very long-chain acyl coenzyme A (CoA) dehydrogenase, short-chain L-3-hydroxyacyl-CoA dehydrogenase, and trifunctional protein deficiencies among the FAO defects). Episodes of exercise-induced myoglobinuria tend to present in later childhood or adolescence; however, myoglobinuria in the first year of life may occur in FAO disorders during catabolic crises precipitated by fasting or infection. The following is a survey of genetic disorders of glycogen and lipid metabolism resulting in myopathy, focusing primarily on those defects, to date, that have presented in the neonatal or early infancy period. Disorders of mitochondrial metabolism are discussed in another chapter.
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PMID:Neonatal metabolic myopathies. 1033 65

Adult-onset carnitine palmitoyltransferase II (CPT II) deficiency is an autosomal recessive disease characterized by muscle pain and stiffness with rhabdomyolysis and myoglobinuria in severe cases. Exercise, fasting, viral infection, anesthesia, or extremes in temperature may trigger symptoms. A 54-year-old woman exhibited a 35-year history of progressive weakness and myopathic symptoms. CPT II activity in the patient's lymphoblasts, cultured skin fibroblasts, and skeletal muscle was reduced to 47, 43, and 13% of normal, respectively. Respiratory chain enzymes were also reduced in muscle ranging from 22 to 49% of their respective normal reference means. beta-oxidation enzymes in fibroblasts ranged from 29 to 63% of normal. The patient, her father, and her 26-year-old son were all heterozygous for the R503C mutation. The patient's son has a lifelong history of myopathic symptoms while his grandfather only had mild weakness during childhood. Analysis of the V368I and M647V polymorphisms in the CPT2 gene showed that the mutant allele is linked to 368I and 647M in this family and that the normal allele is linked to 647V in the affected patient and her son, and to 647M in the patient's father. While the variability in CPT2 gene haplotypes may contribute to the phenotypic complexities in this family, it is also possible that an additional gene defect in the transport of mitochondrial proteins contributes to the complex phenotype in the patient. We present biochemical and molecular evidence for vertical transmission of a variable myopathy caused by heterozygosity for a single mutation, R503C, in the CPT2 gene.
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PMID:A variable myopathy associated with heterozygosity for the R503C mutation in the carnitine palmitoyltransferase II gene. 1087 95

We identified a novel nonsense mutation in the carnitine palmitoyltransferase (CPT; EC 2.3.1.21) II gene in a patient with biochemical evidence of CPT II deficiency. The 39-year-old man suffered from the muscle form of CPT II deficiency. Attacks of myalgia and muscle weakness started in childhood and led to renal failure five times. A mild proximal weakness of the lower limbs was left as a residue. Molecular genetic analysis revealed the common S113L mutation on one allele. On the other allele a novel 4-bp deletion starting at codon 515 (515del4) was found leading to frameshift that results in a stop codon 15 codons upstream. Our data further expand the genetic heterogeneity in patients with CPT II deficiency.
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PMID:A novel nonsense mutation (515del4) in muscle carnitine palmitoyltransferase II deficiency. 1185 39

Mitochondrial carnitine palmitoyltransferase II (CPT II) deficiency is the most common inherited disorder of lipid metabolism in adults. Currently the routine diagnosis is based on the determination of CPT enzyme activity in muscle tissue. We have analysed the tandem mass spectra of serum acylcarnitines of nine CPT II-deficient patients. These spectra were compared to those of a cohort of 99 patients with other neuromuscular disorders and metabolic conditions supposed to cause alterations of the long-chain acylcarnitines. The spectra in CPT II deficiency showed characteristic elevations of C16:0 and C18:1 acylcarnitines while acetylcarnitine C2 was not elevated. In the present study, the ratio (C16:0+C18:1)/C2 has detected all CPT II deficiencies and discriminated them from unspecific alterations of serum acylcarnitines. The ratios of CPT II-deficient patients showed virtually no overlap with those observed in patients with other neuromuscular disorders. We suggest mass spectrometry of serum acylcarnitines as a rapid screening test that should be included early in the diagnostic work-up of patients with recurrent myoglobinuria, recurrent muscular weakness and myalgia.
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PMID:Screening for carnitine palmitoyltransferase II deficiency by tandem mass spectrometry. 1199 76

Increased serum creatine kinase level is a marker of neuromuscular disorders. When combined with exercise intolerance, muscle cramps, fatigue, myoglobinuria, or muscle weakness, metabolic myopathies of a variety of causes should be considered. We encountered an adolescent male with a persistently high serum creatine kinase level and chronic fatigue who was found to have combined partial defects of carnitine palmitoyltransferase II and mitochondrial complex I. Metabolic myopathy may present with chronic fatigue and a persistently high serum creatine kinase level but without muscle weakness and may be attributable to combined enzyme defects.
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PMID:Combined partial deficiencies of carnitine palmitoyltransferase II and mitochondrial complex I presenting as increased serum creatine kinase level. 1208 89

We report the first splice junction mutation to be described in the carnitine palmitoyltransferase (CPT) 2 gene in a patient with the muscle form of CPT II deficiency. The patient, a 25-year-old man, suffered from attacks of myalgia and muscle weakness in early adult life. There was biochemical evidence of CPT II deficiency. Molecular genetic analysis revealed the common S113L mutation on one allele whilst a novel mutation at the splice donor junction in intron 3 was identified on the other allele. Sequencing of reverse transcription polymerase chain reaction (RT-PCR) products clearly demonstrated that this mutation causes the skipping of exon 3, thus establishing its pathogenic role.
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PMID:A splice junction mutation in muscle carnitine palmitoyltransferase II deficiency. 1280 43

A 45-year-old male patient had an episode of acute renal failure with myoglobinuria, myalgias, weakness, and markedly increased serum CK levels. Similar episodes had occurred in the past. Carnitine palmitoyl-transferase II (CPT II) deficiency was documented both biochemically and genetically. Interestingly, muscle biopsy also showed some ragged red fibers (RRF) and complete mitochondrial DNA (mtDNA) sequence disclosed a homoplasmic T3394C point mutation. This mutation is described in Leber's hereditary optic neuropathy (LHON) or in patients with diabetes mellitus.
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PMID:A case of CPT deficiency, homoplasmic mtDNA mutation and ragged red fibers at muscle biopsy. 1616 41

Frailty is a geriatric syndrome characterized by muscle weakness, sarcopenia, and fatigue, and is associated with several adverse health outcomes, including disability. Design of therapeutic interventions for geriatric frailty has been challenging and may be because of inadequate understanding of its biological underpinnings. Carnitine is important for energy production in skeletal muscles and there seems to be a negative correlation between advancing age and muscle carnitine levels. Carnitine deficiency may therefore contribute to geriatric frailty. Age-associated carnitine deficiency from a variety of etiologies, including organic cation transporter (OCTN2) mutation and carnitine palmitoyltransferase II (CPT) deficiency, may potentially explain the relationship between carnitine-associated mitochondrial dysfunction and geriatric frailty. Development of therapeutic agents capable of prevention or reversal of carnitine deficiency in older adults may minimize the occurrence of frailty in geriatric populations.
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PMID:Mechanistic contribution of carnitine deficiency to geriatric frailty. 2022 99


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