Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0026827 (hypotonia)
 5,860 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Congenital methylmalonic aciduria (MMA) is a metabolic disorder inherited by an autosomal recessive trait. The metabolic block is located in the catabolic pathway of propionyl-CoA to succinyl-CoA. Biochemically, four enzymatic defects have been recognized, i.e.: 1. Methylmalonyl-CoA racemase. 2. Methylmalonyl-CoA mutase apoenzyme. 3. Synthesis of desoxyadenosyl-cobalamine. 4. Disturbance at an earlier level of cobalamine metabolism which causes defective synthesis of both vitamin B12-coenzymes. These four enzymatic defects express themselves in three ways: non-vitamin B12-dependent MMA (defects 1 and 2); vitamin B12-dependent MMA (defect 3); MMA associated with homocystinuria (defect 4). The various forms of MMA cannot be distinguished clinically from one another. The disorder manifests itself during the first few days to weeks of life. Principal symptoms and signs are: anorexia, vomiting, muscular hypotonia and metabolic acidosis. The diagnosis is established by determination of methylmalonic acid in plasma, cerebrospinal fluid and urine, as well as by assay of enzyme activities in leukocytes, liver tissue or cultured fibroblasts (from biopsied skin). A prenatal diagnosis is feasible by the examination of cultured amnion cells, amniotic fluid and maternal urine. Therapy of non vitamin B12-dependent MMA calls for reduction of protein intake, particularly that of precursors of methylmalonic acid, such as methionine, threonine, isoleucine and valine. The treatment of vitamin B12-dependent forms is accomplished by i.m. injection of high doses of vitamin B12. No definite statement can be made as yet with regard to long-term prognosis and normalcy of mental development in treated children.
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PMID:[Methylmalonic aciduria. Classification, diagnosis and therapy (author's transl)]. 31 93

The clinical and morphologic findings of three patients with metabolic acidosis, methylmalonic aciduria, and homocystinuria are presented. The clinical evolution of the patients was similar and was characterized in the first weeks of life by failure to thrive, hypotonia, and lethargy associated with pancytopenia and hepatic dysfunction, eventually progressing to severe respiratory insufficiency and renal failure consistent with a hemolytic-uremic syndrome. The patients died at 40, 45, and 75 days of age. Biochemical analyses and complementation studies revealed a congenital anomaly of vitamin B12 metabolism (cobalamin C disease). Postmortem morphologic findings in all three cases were dominated by a thrombotic microangiopathy of the kidneys and lungs, diffuse hepatic steatosis, and megaloblastic changes in the bone marrow. A severe gastritis with striking cystic dysplastic mucosal changes and total absence of parietal and chief cells was a consistent finding in all three cases, the rest of the gastrointestinal tract appearing essentially normal. Cobalamin C disease is an intracellular defect of cobalamin metabolism with possible recessive inheritance that can result in multiorgan failure early in life, with a thrombotic microangiopathy and unusual changes in the gastric mucosa.
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PMID:A congenital anomaly of vitamin B12 metabolism: a study of three cases. 156 46

Functional methionine synthase deficiency is generally characterized by homocystinuria and hypomethioninemia in the absence of methylmalonic aciduria. Patients are divided into two classes, cblE and cblG, on the basis of complementation analysis. Presentation has usually been in the first 2 years of life, but one patient came to medical attention at age 21 years with symptoms initially diagnosed as multiple sclerosis. Common findings among 11 patients (4 with cblE and 7 with cblG) have included megaloblastic anemia (all patients) and various neurological deficits including developmental retardation (10 patients), cerebral atrophy (8 patients), hypotonia (7 patients), EEG abnormalities (6 patients), and nystagmus (5 patients). Hypertonia, seizures, blindness, and ataxia were less frequent. All patients have responded to therapy with cobalamin with resolution of anemia and biochemical abnormalities; neurological deficits resolved more slowly and in some cases incompletely. Hydroxycobalamin has been more effective than cyanocobalamin. Fibroblasts from patients with cblE (5 patients) and cblG (6 patients) all showed decreased intracellular levels of methylcobalamin (MeCbl) and decreased incorporation of label from 5-methyltetrahydrofolate into macromolecules, suggesting decreased activity of the MeCbl-dependent enzyme methionine synthase. Methionine synthase specific activity in extracts of all cblE fibroblasts was normal or near-normal under standard reducing conditions; synthase specific activity in extracts of 5 cblG patients was low but was high in a 6th patient measured in another laboratory. Thus, there is heterogeneity among patients with functional methionine synthase deficiency both in clinical presentation and in the results of biochemical studies of cultured cells.
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PMID:Functional methionine synthase deficiency (cblE and cblG): clinical and biochemical heterogeneity. 268 21

We describe a female child from a consanguineous marriage (uncle-niece) with hypermethioninemia and hypermethioninuria without homocystinuria. She had several signs and symptoms previously undescribed in this pathology as growth retardation, generalized hypotonia, digestive disturbances, white skin, hypochromia of iris, thin, sparse and blond scalp hair. The pedigree suggests an autosomal recessive inheritance pattern.
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PMID:[Hypermethioninemia. Apropos of a case in a consanguineous couple]. 747 Feb 71

The clbC form of methylmalonic acidaemia is a rare and poorly understood condition which results from impaired biosynthesis of methylcobalamin and adenosylcobalamin. The consequent functional deficiencies of methylmalonyl-CoA mutase and methionine synthase produce both methylmalonic aciduria and homocystinuria. Systemic symptoms and neurological decompensation comprise the clinical phenotype. In an effort to clarify the phenotype and prognosis, we obtained clinical information on 50 patients with methylmalonic acidaemia whose cells had been assigned to the cblC complementation group. We identified two distinct phenotypes; they differed in age of onset, presence of systemic symptoms, type of neurological symptoms, and outcome after diagnosis and treatment. Forty-four patients presented in the first year of life. Feeding difficulties, neurological dysfunction (hypotonia, seizures, developmental delay), and ophthalmological and haematological abnormalities characterized their clinical picture. About one-quarter of those patients died. Survival was associated with neurological impairment; only one infant was neurologically intact at follow-up. Onset in childhood, in contrast, was associated with less severe haematological abnormalities, largely involving the red cell series. Extrapyramidal signs, dementia, delirium or psychosis characterized the neurological findings. Survival, with mild to moderate disability in some, was typical in patients with later onset. Treatment in both groups included hydroxycobalamin, betaine and carnitine; complete normalization of biochemical parameters was rare.
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PMID:Clinical heterogeneity and prognosis in combined methylmalonic aciduria and homocystinuria (cblC). 926 89

Cobalamin C (cblC) defects result in decreased activity of both methylmalonyl-CoA mutase and N5-methyltetrahydrofolate:homocysteine methyltransferase (methionine synthase), with subsequent methylmalonic acid-uria and homocystinuria. Patients typically show failure to thrive, developmental delay and megaloblastic anaemia. Vitamin B12 therapy has been beneficial in some cases. We report a now 4-year-old Hispanic girl with cblC disease documented by complementation analysis, with progressive neurological deterioration and worsening head MRI changes while on intramuscular hydroxocobalamin begun at age 3 weeks. Oral carnitine and folic acid were added at age 1 year. Blood levels of methylmalonic acid were reduced to treatment ranges. In the absence of acute metabolic crises, she developed microcephaly, progressive hypotonia and decreased interactiveness. Funduscopic examination was normal at age 13 months. At age 19 months, she developed nystagmus, and darkly pigmented fundi and sclerotic retinal vessels were observed on examination. Her neonatal head MRI was normal. By age 1 year, the MRI showed diffuse white-matter loss with secondary third and lateral ventricle enlargement, a thin corpus callosum, and normal basal ganglia. At age 15 months, progression of the white-matter loss, as well as hyperintense globi pallidi, were present. Interval progression of both grey- and white-matter loss was seen at age 27 months. We therefore caution that progressive neurological deterioration and head MRI abnormalities may still occur in cblC disease, despite early initiation of hydroxocobalamin therapy and improvement in toxic metabolite concentrations in physiological fluids.
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PMID:Progressive neurological deterioration and MRI changes in cblC methylmalonic acidaemia treated with hydroxocobalamin. 1039 92

Methylenetetrahydrofolate reductase deficiency is the most common inborn error of folate metabolism and should be suspected when homocystinuria is combined with hypomethioninemia. The main clinical findings are neurologic signs such as severe developmental delay, marked hypotonia, seizures, microcephaly, apnea, and coma. Most patients present in early life. The infantile form is severe, with rapid deterioration leading to death usually within 1 year. Treatment with betaine has been shown to be efficient in lowering homocysteine concentrations and returning methionine to normal, but the clinical response is variable. We report two brothers with methylenetetrahydrofolate reductase deficiency: the first was undiagnosed and died at 8 months of age from neurologic deterioration and apnea, while his brother, who was treated with betaine from the age of 4 months, is now 3 years old and has developmental delay.
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PMID:Methylenetetrahydrofolate reductase deficiency: importance of early diagnosis. 1096 93

We performed serial electroencephalograms (EEG) in a newborn with methylmalonic aciduria and homocystinuria to assess the effects of hydroxycobalamin (OHcbl) therapy on the CNS. Diagnosis was made at 22 days of age: she had torpor, failure to thrive and hypotonia of the limbs, and intermittent opisthotonus. The first EEG, performed on the first day of therapy, showed abnormal and immature transients, low voltage and very long flat periods in the discontinuous part of the tracing. These features quickly improved during therapy. After 13 days of OHcbl therapy, the EEG tracing became normal for conceptional age and showed normal sleep phases with only minor anomalies; only mild hypotonia still remained and biochemical parameters normalized. The decrease in blood homocysteine (index of blood detoxification) was statistically correlated to the reduction of the length of flat periods in EEG (p < 0.01). In conclusion, changes in neonatal EEG, particularly the length of interburst periods in the intermittent part of the tracing, appeared to be a reliable index for evaluating drug effectiveness in methylmalonic aciduria and homocystinuria.
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PMID:EEG in assessing hydroxycobalamin therapy in neonatal methylmalonic aciduria with homocystinuria. 1109 15

Methylmalonic aciduria and homocystinuria is a very rare inborn error of cellular cobalamin (Cbl) metabolism. We describe the biochemical evolution and clinical course of a boy with neonatal onset CblC mutant defect.Born after a normal pregnancy, the patient developed general hypotonia and severe feeding difficulties at 5 days of life. Diagnosis of methylmalonic aciduria and homocystinuria was established by amino-acid and organic acid analysis and was confirmed by enzyme and genetic studies. The patient was initially treated with parenteral hydroxocobalamin (1 mg/day), oral carnitine (100 mg/kg/day) and a restricted protein diet. This treatment returned methylmalonic acid levels to normal. Despite the parenteral hydroxocobalamin therapy, the patient showed no improvement in neurological dysfunction, hypotonia or developmental delay. Oral betaine supplementation (3 g/day) from months 3-15 reduced plasma total homocysteine and homocystinuria. The patient showed clinical improvement in neurological and growth development. We conclude that early betaine therapy was safe and effective in our patient with neonatal onset methylmalonic aciduria and homocystinuria type CblC.
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PMID:[Neonatal onset methylmalonic aciduria and homocystinuria:Biochemical and clinical improvement with betaine therapy]. 1192 78

Combined methylmalonic aciduria and homocystinuria (MMA-HC) is a rare metabolic disease characterized by an inborn defect in B12 vitamin metabolism. This case report concerns an 11-year-old patient with MMA-HC, which developed during the neonatal period. The patient shows some of the facial features that were already reported in the literature (high forehead, large floppy, low-set ears, flat philtrum and hypotonia of perioral and masticatory muscles) but no dolichocephalic skull nor long face. The patient also shows signs that had not been previously described: epicanthal folds, broad nasal bridge, long and flat philtrum, amimic expression and, particularly, a postural alteration (the head is rotated and bent towards the left shoulder, which is lower than the right one). Such alteration can be attributed to visual impairment and is responsible for breaking muscular and skeletal balance in the frontal plane, thus causing the horizontal planes of both maxillary bones to converge towards the right--as highlighted by the cephalometric analysis of the Teleradio-graph of the skull in Posteroanterior projection according to Ricketts. As for the patient's teeth, eruption times are normal, but there are anomalies of shape (chisel-like central incisors). As far as dental caries is concerned, the patient's DMFT is 4 (D=4, M=0, F=0). This clinical case highlights the need for dental prevention programs suggested by the pediatrician once the pathology is diagnosed.
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PMID:Oral and craniofacial findings in a patient with methylmalonic aciduria and homocystinuria: review and a case report. 2035 39


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