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)

Carbohydrate-deficient glycoprotein syndrome type 1 (CDG1 or Jaeken syndrome) is the prototype of a class of genetic multisystem disorders characterized by defective glycosylation of glycoconjugates. It is mostly a severe disorder which presents neonatally. There is a severe encephalopathy with axial hypotonia, abnormal eye movements and pronounced psychomotor retardation, as well as a peripheral neuropathy, cerebellar hypoplasia and retinitis pigmentosa. The patients show a peculiar distribution of subcutaneous fat, nipple retraction and hypogonadism. There is a 20% lethality in the first years of life due to severe infections, liver insufficiency or cardiomyopathy. CDG1 shows an autosomal recessive mode of inheritance and has been mapped to chromosome 16p. Most patients show a deficiency of phosphomannomutase (PMM)8, an enzyme necessary for the synthesis of GDP-mannose. We have cloned the PMM1 gene, which is on chromosome 22q13 (ref.9). We now report the identification of a second human PMM gene, PMM2, which is located on 16p13 and which encodes a protein with 66% identity to PMM1. We found eleven different missense mutations in PMM2 in 16 CDG1 patients from different geographical origins and with a documented phosphomannomutase deficiency. Our results give conclusive support to the biochemical finding that the phosphomannomutase deficiency is the basis for CDG1.
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PMID:Mutations in PMM2, a phosphomannomutase gene on chromosome 16p13, in carbohydrate-deficient glycoprotein type I syndrome (Jaeken syndrome). 914 Apr 1

Carbohydrate-deficient glycoprotein syndrome type 1 (CDGS-1) is an autosomal recessive hereditary metabolic disorder, the gene locus of which is chromosome 16p13. The disorder is characterised by genetic heterogeneity, and by decrease in the gene product, phosphomannomutase 2, though the heterogeneity is far less manifest in affected Swedish families. Its incidence is 1/80,000 live births, and the under-5 mortality rate over 30 per cent. The causes of death are liver failure, cardiac tamponade, haemorrhaging, and severe infection. The characteristic biochemical aberration is the occurrence of deficient carbohydrate chains in many but not all circulating glycoproteins, and the serum and blood concentrations of some glycoproteins may be above or below normal. These changes may improve over time, but never normalise. The clinical picture is generally more problematic during the first years of life when psychomotor retardation is complicated by failure to thrive, liver dysfunction, pericardial effusions, and stroke-like episodes. In addition, strabismus, lipocutaneous anomalies, and gluteal fat pads are always present, and muscular hypotonia and restricted joint mobility are common. Failure to thrive is common, with vomiting and diarrhoea and subsequent slow growth. Inflammation is a constant finding in the liver, and very common in the small bowel. Pancreatic function is also affected. Pericardial effusion has been reported in 50 per cent of the youngest children, requiring pericardectomy in 30 per cent of cases. Haemorrhaging and thromboembolic complications may occur, and the serum concentrations of several factors and inhibitors are low, particularly those of factors V and XI, protein C and antithrombin. Stroke-like episodes occur in about 30 per cent of cases, often following an infection, with coma lasting for hours to several days. Such sequelae as hemiplegia, blindness, and other focal neurological pathology have been observed transiently. Diagnosis is based on the serum carbohydrate-deficient transferrin level, verified by isoelectric focusing. Molecular genetic procedures enable point mutations to be identified and prenatal diagnosis to be performed in many families.
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PMID:[CDGS-1--a recently discovered hereditary metabolic disease. Multiple organ manifestations, incidence 1/80,000, difficult to treat]. 988 93

A 10-month old girl is described with a serum transferrin isoform abnormality of the same kind as in two previously reported girls with carbohydrate-deficient glycoprotein syndrome type III. This patient presented with joint abnormalities and rapidly developing hypsarrhythmia, hypotonia, psychomotor delay and growth retardation. Fingers, toes, nails and local skin were dysmorphic. She had pale optic discs, thoracic syringomyelia and frontal lobe atrophy at three months. The CDT value in serum was greatly elevated. Several carbohydrate-deficient isoforms were found in transferrin (four), alpha1-antitrypsin (three), antithrombin (two) and thyroxine-binding globulin (four). Mutations in the CDGS 1-gene were excluded. The CDGS III glycoprotein abnormality most probably represents a distinct disorder of glycoprotein metabolism, and needs to be considered in unclear hypsarrhythmia with developmental delay. Dysmorphic features may be added to this syndrome.
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PMID:A neurodystrophic syndrome resembling carbohydrate-deficient glycoprotein syndrome type III. 1040 91

The clinical phenotype and the molecular defect of a patient with a new subtype of congenital disorders of glycosylation (CDG-Ic, formerly designated as CDGS type V) characterized by a deficiency of Dol-P-Glc: Man9GlcNAc2-PP-Dol glucosyltransferase is described. The clinical picture presents with several features similar to CDG-Ia (phosphomannomutase 2 deficiency) such as hypotonia and atactic-dystonic movements. In contrast to CDG-Ia, the course of the disease appears milder. The head growth, the functioning of the peripheral nerves and the initial cerebellar development were normal. Sequencing of the patient's Dol-P-Glc: Man9GlcNAc2-PP-Dol glucosyltransferase cDNA revealed an in-frame deletion of three nucleotides leading to the loss of isoleucine 299.
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PMID:Congenital disorder of glycosylation-Ic: case report and genetic defect. 1083 77

Congenital disorder of glycosylation Ia is the most common defect of glycosylation and is due to mutations in phosphomannomutase 2. This leads to aberrant N-linked oligosaccharides. The phenotype of CDG Ia reflects the essential nature of glycosylation and patients typically present with multiple organs affected, with hypotonia, developmental delay, inverted nipples and abnormal fat pads. Later features include retinitis pigmentosa, stroke, cerebellar atrophy and malabsorption. Approximately 20% of patients die in the first year of life and infection is the most common cause of death. Immunological function has not previously been investigated in these patients and the critical role of oligosaccharides on adhesion molecules suggested that haematopoietic cell migration and communication could be disrupted by mutations in phosphomannomutase 2. We characterized the clinical features, performed standard immunological evaluations, and performed specific analyses of neutrophil adhesion molecules on two patients to address this question. Patient neutrophils had diminished chemotaxis but expressed comparable levels of adhesion molecules and rolled on artificial endothelium equivalently to control neutrophils. The most significant feature of the patients' immunological function was poor vaccine responses. These two affected patients were begun on intravenous immunoglobulin with some improvement in their infections.
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PMID:Recurrent infections and immunological dysfunction in congenital disorder of glycosylation Ia (CDG Ia). 1682 48

Congenital disorders of glycosylation are a heterogeneous group of disorders with multisystemic involvement. The most common form is phosphomannomutase deficiency or congenital disorders of glycosylation type Ia with an autosomal recessive inheritance and incidence estimated at 1/20000-1/50000 live born. Congenital disorders of glycosylation Ia can manifest as severe multisystemic disease of infancy or milder disorder with only neurological problems including ataxia, hypotonia, and psychomotor retardation. The brain pathological findings in congenital disorders of glycosylation type Ia patients corroborate with cerebellar dysfunction. Usually the most affected part is the anterior lobe of the vermis. Microscopic analysis demonstrates the prominent Purkinje cell loss and subtotal loss of the external and internal granule cell layers. The authors present clinical and pathological picture of a 4-month-old girl with congenital disorders of glycosylation type Ia, additionally complicated by congenital cytomegalovirus infection. The diagnosis was confirmed by low phosphomannomutase activity in patient's fibroblasts and mutations on both alleles of phosphomannomutase 2 gene.
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PMID:CDG type Ia and congenital cytomegalovirus infection: two coexisting conditions. 1916 13

Congenital disorders of glycosylation (CDG) are genetic diseases due to defects in the synthesis or the attachment of the glycan moiety of glycoproteins and glycolipids. They can be divided into four groups: disorders of protein N-glycosylation, disorders of protein O-glycosylation, disorders of lipid glycosylation, and disorders of other glycosylation pathways and of multiple glycosylation pathways. Of the more than 40 reported CDG, some 80% are neurological or have an important neurological component. By far the most common neurological CDG is phosphomannomutase 2 deficiency. Isoelectrofocusing of serum transferrin, the most widely used screening test, picks up only CDG associated with sialic acid deficiency of N-linked glycans. Predominant neurological signs and symptoms are psychomotor retardation, epilepsy, hypotonia, hyporeflexia, strabismus, retinitis pigmentosa, polyneuropathy, myopathy, and cerebellar hypotrophy/hypoplasia. All known neurological CDG have an autosomal recessive inheritance except for IAP-CDG, an X-linked pure mental retardation syndrome. No curative or effective treatment is available for neurological CDG. Since at least 1% of the genome is involved in glycosylation, it is likely that the large majority of CDG is yet to be discovered. In 2008, a novel nomenclature was introduced using the gene symbol followed by -CDG, e.g., CDG-Ia becomes PMM2-CDG. CDG should be looked for in any unexplained neurological syndrome.
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PMID:Congenital disorders of glycosylation. 2362 97

Congenital disorders of glycosylation (CDG) are a group of hereditary diseases characterised by deficiency of enzymes involved in proteins glycosylation. We describe the clinical case of a neonate with CDG type 1a, nowadays designated phosphomannomutase 2 (PMM2)-CDG. Physical examination showed an abnormal facies, axial hypotonia, abnormal fat distribution, inverted nipples, non-palpable testicles and arachnodactyly. Progressive multiple system organ involvement and worsening of hypertrophic cardiomyopathy occurred. Metabolic study revealed a CDG disturbance, which was confirmed by genetic study. The following mutations were identified: c.193G>T; p.D65Y and c.470T>C; p.F157S. Clinical deterioration was inevitable with multisystemic failure and death. CDG represents a challenge for physicians due to multiple organ involvement, and heterogeneous clinical manifestations. The neonatal form is usually associated with the worst prognosis.
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PMID:Congenital disorders of glycosylation with neonatal presentation. 2473 49

The neuron-restricted isoform 3 of the plasma membrane Ca2+ ATPase plays a major role in the regulation of Ca2+ homeostasis in the brain, where the precise control of Ca2+ signaling is a necessity. Several function-affecting genetic mutations in the PMCA3 pump associated to X-linked congenital cerebellar ataxias have indeed been described. Interestingly, the presence of co-occurring mutations in additional genes suggest their synergistic action in generating the neurological phenotype as digenic modulators of the role of PMCA3 in the pathologies. Here we report a novel PMCA3 mutation (G733R substitution) in the catalytic P-domain of the pump in a patient affected by non-progressive ataxia, muscular hypotonia, dysmetria and nystagmus. Biochemical studies of the pump have revealed impaired ability to control cellular Ca2+ handling both under basal and under stimulated conditions. A combined analysis by homology modeling and molecular dynamics have revealed a role for the mutated residue in maintaining the correct 3D configuration of the local structure of the pump. Mutation analysis in the patient has revealed two additional function-impairing compound heterozygous missense mutations (R123Q and G214S substitution) in phosphomannomutase 2 (PMM2), a protein that catalyzes the isomerization of mannose 6-phosphate to mannose 1-phosphate. These mutations are known to be associated with Type Ia congenital disorder of glycosylation (PMM2-CDG), the most common group of disorders of N-glycosylation. The findings highlight the association of PMCA3 mutations to cerebellar ataxia and strengthen the possibility that PMCAs act as digenic modulators in Ca2+-linked pathologies.
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PMID:A novel PMCA3 mutation in an ataxic patient with hypomorphic phosphomannomutase 2 (PMM2) heterozygote mutations: Biochemical characterization of the pump defect. 2880 51