Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.4.1.18 (branching enzyme)
 628 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In the diagnosis of metabolic myopathies the use of biochemical methods, in addition to morphological examination of muscle biopsies, is often necessary in order to identify a specific metabolic defect. In order to narrow down the spectrum of biochemical methods, extensive clinical investigation and morphological examination, including histology, enzyme histochemistry and electromicroscopy if necessary have to be done beforehand. Patients are classified in the following groups: 1) progressive muscular weakness and/or muscle wasting with storage of a) glycogen, b) lipid or c) mitochondrial alterations; 2) recurrent rhabdomyolysis induced by fasting or exercise a) with glycogen storage or b) without any specific morphological alterations. The spectrum of metabolic defects comprises disorders of glycogen and glucose metabolism (deficiency of acid maltase, debranching and branching enzyme, phosphorylase, phosphofructokinase and other glycolytic enzymes), lipid metabolism (carnitine deficiency, carnitine palmitoyl transferase deficiency), mitochondria (respiratory chain disorders, pyruvate dehydrogenase deficiency) and others such as adenylate deaminase deficiency. In some of these e.g. infantile acid maltase deficiency and mitochondriopathies, it is clinically more important when organs other than muscle are affected; however, muscle biopsy is a useful substrate for diagnosis of these metabolic disorders.
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PMID:[Diagnostic significance of muscle biopsies in metabolic myopathies. II. Clinical biochemistry]. 659 Sep 24

Type IV glycogenosis (polyglucosan body disease) is a rare congenital autosomal recessive inherited disorder, caused by lack of the branching enzyme (amylo-1,4-1,6 transglucosidase). This deficiency leads to storage of abnormal glycogen (polyglucosan bodies) in the liver and other tissues. The clinical onset of the disease is insidious with non-specific gastrointestinal symptoms followed by progressive hepatic failure. Usually patients die due to hepatic cirrhosis within 4 years. Sometimes myopathy of the heart and skeletal muscle is also present. In these cases, the clinical onset is often later than in typical cases. We report on two brothers with primarily cardiac manifestation and late onset of the disease. The older one started to suffer from progressive dilated cardiomyopathy at the age of 18 years, presenting with severe heart failure, hepatosplenomegaly, ascites and peripheral oedema. He also demonstrated myopathy and muscular atrophy especially of the shoulder and lower limbs. Initially he improved on medical therapy, but one year later severe heart failure recurred followed shortly afterwards by sudden cardiac death. Right heart and skeletal muscle biopsies were performed while he was alive. These, as well as the autopsy, revealed massive accumulation of polyglucosan bodies. In both heart and skeletal muscle, complete branching enzyme deficiency could be proven. His 14-year-old brother showed similar clinical findings of mild dilated cardiomyopathy. His muscle biopsy also revealed polyglucosan body myopathy. Thus, in young patients presenting with congestive cardiomyopathy, type IV glycogenosis has to be considered in the differential diagnosis.
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PMID:A new variant of type IV glycogenosis with primary cardiac manifestation and complete branching enzyme deficiency. In vivo detection by heart muscle biopsy. 888 67