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

Bejar et al. described increased concentrations of valine, leucine and isoleucine in the plasma of 2 patients with cerebral gigantism (Sotos-syndrome). We have recently investigated a group of 14 children with Sotos-syndrome. The data of the plasma amino-acid determinations were compared with those of aged-matched healthy controls, 9 children with benign muscular hypotonia, 10 children with Down's syndrome and finally with those of 13 children with familial tall stature. The mean concentration of serine, glutamic acid, valine, isoleucine, leucine and phenylalanine was lower in the patients with Sotos-syndrome when compared to the healthy control group. However, all patients with benign muscular hypotonia and Down's syndrome showed increased concentrations of proline, glycine, alanine, ornithine and lysine in the plasma whereas the mean values of the children with familial tall stature differed only slightly from those of the controls. The levels of the plasma-aminoacids in patients with Sotos-syndrome were only slightly different from those in patients with muscular hypotonia, but generally lower than in tall children. We conclude that the determination of plasma-aminoacids is of no value in the diagnosis of Sotos-syndrome.
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PMID:[Amino acids in plasma of patients with cerebral gigantism (Sotos syndrome) (author's transl)]. 645 99

Maple Syrup Urine Disease (branched-chain alpha-ketoacid dehydrogenase deficiency) in a neonate who was too ill to feed was successfully treated with total parenteral nutrition which promoted protein synthesis thereby allowing accumulated branched-chain amino acids to be incorporated into body protein. Total parenteral nutrition was initiated after the patient was unable to continue nasogastric feeding and peritoneal dialysis had failed due to the patient's hypotonia. A special total parenteral nutrition mixture lacking leucine, isoleucine, and valine was supplemented with Intralipid to provide an average of 125 kcal/kg/day. Nitrogen balance documented a normal nitrogen retention rate of 185 mg N/kg/day. The various branched-chain amino acids were added individually to the intravenous solution as the plasma concentration of each decreased. The intake of the branched-chain amino acids (isoleucine 65 mg/kg/day, valine 78 mg/kg/day, and leucine 159 mg/kg/day) was approximately two-thirds of that of the normal breast-fed infant, equivalent to the normal rate of incorporation of these essential amino acids into protein. Total parenteral nutrition achieves and sustains branched-chain amino acids removal efficiently with fewer risks than multiple exchange transfusions or peritoneal dialysis. A combination of total parenteral nutrition with one of these alternative modes of therapy may be most useful in the acutely toxic patient
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PMID:Total parenteral nutrition therapy of toxic maple syrup urine disease. 680 24

A boy, aged 7 months, of consanguineous parents presented with an acute onset of vomiting, fever, nonketotic hypoglycemia and acidosis and died from cardiac arrest after ventricular fibrillation. He had hepatomegaly and echocardiographically a non-obstructive cardiomyopathy. Autopsy was not allowed. After birth the child had suffered from a severe respiratory distress syndrome, transient metabolic acidosis and had a sweaty feet odour. Later on, development was retarded with a severe muscular hypotonia. Post mortem, numerous unusual organic acids were found in high concentrations in urine, e.g. dicarbonic acids, 2-hydroxyisobutyric, isovaleric, 3-hydroxyisovaleric acid, N-acyl glycines, isovalerylglutamic acid and sarcosine. This pattern indicated deficiencies of several acyl-Co A dehydrogenases in the metabolism of leucine, isoleucine, valine, lysine, short-chain fatty acids and sarcosine. This could be confirmed using cultured skin fibroblasts which were shown to degrade the corresponding labeled substrates insufficiently to 14CO2. It is assumed that the functional multiple acyl-Co A dehydrogenation deficiency is caused by a deficiency of a common link in the electron transfer system of these dehydrogenases which is inherited autosomal recessively in this family. Among the 12 patients reported, 7 died within the first 5 days of age.
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PMID:Multiple acyl-Co A dehydrogenation deficiency (MADD) in a boy with nonketotic hypoglycemia, hepatomegaly, muscle hypotonia and cardiomyopathy. Detection of N-isovalerylglutamic acid and its monoamide. 686 97

A 15-month-old girl with propionic acidemia presented a failure to thrive and muscular hypotonia, who had been treated with diets low in leucine, valine, isoleucine, threonine and methionine. Supplementation with leucine gave her a catch up growth and brought about an improvement in muscular hypotonia in parallel with restoration of plasma leucine which had been below normal range during the treatment with the above diets. Oral loading test of leucine produced no ketoacidosis. These findings indicate that the restriction of leucine is not necessary in the dietary management of propionic acidemia.
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PMID:Dietary therapy in a girl with propionic acidemia: supplement with leucine resulted in catch up growth. 686 77

Pelizaeus Merzbacher disease (PMD) is an X-linked recessive disorder of the central nervous system myelination caused by mutations involving the proteolipid protein gene (PLP). Early nystagmus and developmental delay, progressive pyramidal, cerebellar and dystonic signs as well as white matter changes in brain MRI are typical for PMD. The PLP gene can be affected by two major types of mutations. A duplication of the whole PLP gene is the most common mutation and results usually in the milder classical phenotype, whereas point mutations in PLP gene often result in the rarer and more severe connatal form of PMD. The PLP protein is a higly conserved across species and is identical in human, mouse and rat. We describe a 13-year-old Czech boy with an early and severe developmental delay. His maternal uncle died at the age of one year and was also early and severely psychomotoricly retarded. The patient was the first child of healthy unrelated parents born after an uneventful pregnancy and delivery in 1988. Hyperbilirubinemia and bronchopneumonia and early stridor complicated his neonatal period. Diffuse hypotonia, nystagmus, psychomotor retardation, visual and hearing impairment have been observed in the patient since the age of 6 weeks. White matter abnormalities, cortical and periventricular atrophy were detected by MRI at the age of 6 and 11 years, respectively. Despite these signs and results an accurate clinical diagnosis was unclear until the age of 11 years. Last neurological examination in 1999 showed no nystagmus anymore, but extremely dystrophic limbs, truncal deformation, due to severe scoliosis, tetraplegia with hyperreflexia in C5C7 and areflexia L2S2 and positive pyramidal signs. The boy had no visual or speech contact. DNA tests followed the clinical suspicion for PMD. At first, duplication of PLP gene was excluded by quantitative comparative PCR. Direct sequencing of PLP gene detected a novel mutation in exon 6, a missense mutation 725C-->A (Ala242Glu) in the patient and in his mother and later also in his maternal grandmother. The same codon, but to valine (Ala242Val) is mutated in jimpy(msd) mouse, which is the frequently used animal model for PMD. Prenatal diagnosis for the next pregnancy has been offered to the family. The patient died recently at the age of 13 years due to respiratory failure. Our results support the data on the importance of this conserved amino acid alanine at codon 242.
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PMID:A severe connatal form of Pelizaeus Merzbacher disease in a Czech boy caused by a novel mutation (725C>A, Ala242Glu) at the 'jimpy(msd) codon' in the PLP gene. 1178 21

N-terminal acetylation of proteins is a widespread and highly conserved process. Aminoacylase 1 (ACY1; EC 3.5.14) is the most abundant of the aminoacylases, a class of enzymes involved in hydrolysis of N-acetylated proteins. Here, we present four children with genetic deficiency of ACY1. They were identified through organic acid analyses using gas chromatography-mass spectrometry, revealing increased urinary excretion of several N-acetylated amino acids, including the derivatives of methionine, glutamic acid, alanine, leucine, glycine, valine, and isoleucine. Nuclear magnetic resonance spectroscopy analysis of urine samples detected a distinct pattern of N-acetylated metabolites, consistent with ACY1 dysfunction. Functional analyses of patients' lymphoblasts demonstrated ACY1 deficiency. Mutation analysis uncovered recessive loss-of-function or missense ACY1 mutations in all four individuals affected. We conclude that ACY1 mutations in these children led to functional ACY1 deficiency and excretion of N-acetylated amino acids. Questions remain, however, as to the clinical significance of ACY1 deficiency. The ACY1-deficient individuals were ascertained through urine metabolic screening because of unspecific psychomotor delay (one subject), psychomotor delay with atrophy of the vermis and syringomyelia (one subject), marked muscular hypotonia (one subject), and follow-up for early treated biotinidase deficiency and normal clinical findings (one subject). Because ACY1 is evolutionarily conserved in fish, frog, mouse, and human and is expressed in the central nervous system (CNS) in human, a role in CNS function or development is conceivable but has yet to be demonstrated. Thus, at this point, we cannot state whether ACY1 deficiency has pathogenic significance with pleiotropic clinical expression or is simply a biochemical variant. Awareness of this new genetic entity may help both in delineating its clinical significance and in avoiding erroneous diagnoses.
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PMID:Mutations in ACY1, the gene encoding aminoacylase 1, cause a novel inborn error of metabolism. 1646 18

The diagnosis of a 14-year-old girl with a new homoallelic mutation in the sepiapterin reductase (SR) gene is reported. Initially she presented at the age of 2 with hypotonia and mild cognitive developmental delay, and was diagnosed as having mild methylmalonic aciduria, which was recently identified as methylmalonylCoA racemase deficiency, a new defect in valine-isoleucine metabolism. After a 12-year progression of her neurologic condition, which had made her wheelchair-bound at the age of 6, dystonia with diurnal variation had become apparent. At the age of 14 this finding led to rapid diagnosis of SR deficiency. The diagnostic approach with CSF neurotransmitter and pterins analysis and combined phenylalanine/BH(4) loading test, and finally measurement of sepiapterin in CSF is illustrative for the diagnosis of SR deficiency. As in all other patients with this new defect, very low levels of homovanillic acid and 5-hydroxyindoleacetic acid and high levels of biopterin and sepiapterin in the CSF are the diagnostic hallmark. The girl improved dramatically on treatment with L-DOPA and 5-hydroxytryptophan. The initial diagnosis of methylmalonic aciduria may afterwards be considered to have not significantly contributed to her clinical condition and only has led to a long delay of the clinically relevant diagnosis of SR deficiency. Although the clinical condition of this recently recognized autosomal recessive defect in pterin metabolism is complex and many symptoms can occur in variable severity and time of onset, dystonia with diurnal variation is a characteristic finding, as shown in nearly all patients described so far. The rapid and favourable response on treatment with L-DOPA warrants the classification of SR deficiency as another autosomal recessive type of DOPA-responsive dystonia (DRD). This classification is important to improve the awareness of clinicians that more than one metabolic defect can underlie the phenotype of a DOPA-responsive dystonic disorder and that dystonia should always trigger a rapid diagnosis of the underlying neurotransmitter synthesis defect, in view of the excellent treatability of a DRD.
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PMID:Sepiapterin reductase deficiency an autosomal recessive DOPA-responsive dystonia. 1665 Jul 84

Maple syrup urine disease (MSUD) is an inborn error of metabolism resulting from a defect in the oxidation of the branched-chain amino acids leucine, isoleucine, and valine. Patients present in early infancy with brain edema; delay in diagnosis and treatment is common and associated with residual neurologic damage, which includes alternating muscular hypotonia and hypertonia, dystonia, and seizures. These signs can result in trauma, especially to the anterior maxilla, which is the most traumatized region. In patients with MSUD, a fixed prosthesis is recommended because a removable one can be dangerous because of the risk of aspiration. Rehabilitation, using dental implants, is especially challenging in these patients because of the strong muscular forces of the tongue and lips. An implant-supported fixed prosthesis might provide an effective functional, esthetic, and predictable solution for patients with late-treated MSUD. The present report describes a 10-year follow-up of the successful, posttraumatic use of a dental implant to replace an anterior maxillary tooth in a patient with MSUD.
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PMID:Posttraumatic dental implant placement in a patient with maple syrup urine disease. 1676 96

Only a single patient with 3-hydroxyisobutyryl-CoA hydrolase deficiency has been described in the literature, and the molecular basis of this inborn error of valine catabolism has remained unknown until now. Here, we present a second patient with 3-hydroxyisobutyryl-CoA hydrolase deficiency, who was identified through blood spot acylcarnitine analysis showing persistently increased levels of hydroxy-C(4)-carnitine. Both patients manifested hypotonia, poor feeding, motor delay, and subsequent neurological regression in infancy. Additional features in the newly identified patient included episodes of ketoacidosis and Leigh-like changes in the basal ganglia on a magnetic resonance imaging scan. In cultured skin fibroblasts from both patients, the 3-hydroxyisobutyryl-CoA hydrolase activity was deficient, and virtually no 3-hydroxyisobutyryl-CoA hydrolase protein could be detected by western blotting. Molecular analysis in both patients uncovered mutations in the HIBCH gene, including one missense mutation in a conserved part of the protein and two mutations affecting splicing. A carefully interpreted acylcarnitine profile will allow more patients with 3-hydroxyisobutyryl-CoA hydrolase deficiency to be diagnosed.
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PMID:Mutations in the gene encoding 3-hydroxyisobutyryl-CoA hydrolase results in progressive infantile neurodegeneration. 1716 Sep 7


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