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

Adenylosuccinate lyase (ADSL) catalyzes two steps in purine nucleotide metabolism-the 8th step in the de novo pathway: conversion of succinylaminoimidazole carboxamide ribotide (SAICAR) to aminoimidazole carboxamide ribotide (AICAR), and conversion of adenylosuccinate (S-AMP) to adenylate (AMP) in the purine nucleotide cycle. To date, over 50 patients have been reported suffering from ADSL deficiency. We report all seven so far diagnosed Polish patients with this defect. Most of our patients shared intractable seizures and psychomotor retardation since the neonatal period and had biochemical evidence of severe (type I) deficiency. Two patients with type II suffered only from mild/moderate psychomotor retardation and showed a transientvisual contact disturbance. One patient had a fatal neonatal form of ADSL deficiency with lack of spontaneous movement, respiratory failure, severe encephalopathy and intractable seizures. Analysis of the ADSL gene showed that four apparently unrelated patients carried a R426H mutation (two homozygous and two compound heterozygous). With the exception of the latter mutation, a Y114H mutation that had been reported previously, and a novel mutation T242I, all other mutations (including D268H and three novel S23R, D215H and I351T mutations) were found only in single families in single alleles. A search for this disorder should be included in the screening program of all infants with unexplained neonatal seizures, severe infantile epileptic encephalopathy, developmental delay, hypotonia, and/or autistic features.
Mol Genet Metab 2008 Aug
PMID:Clinical, biochemical and molecular findings in seven Polish patients with adenylosuccinate lyase deficiency. 1852 58

We report a patient with a unique and complex cytogenetic abnormality involving mosaicism for a small ring X and deleted Xp derivative chromosome with tandem duplication at the break point. The patient presented with failure to thrive, muscular hypotonia, and minor facial anatomic anomalies, all concerning for Turner syndrome. Brain MRI revealed mild thinning of the corpus callosum, an apparent decrease in ventricular white matter volume, and an asymmetric myelination pattern. Array comparative genome hybridization analysis revealed mosaicism for the X chromosome, deletion of the short arm of an X chromosome, and a duplication of chromosome region Xp11.21-p11.22. G-banded chromosome and FISH analyses revealed three abnormal cell lines: 46,X,der(X)del(X)(p11.23)dup(X)(p11.21p11.22)/46,X,r(X)(q11.1q13.1)/45,X. The small ring X chromosome was estimated to be 5.2 Mb in size and encompassed the centromere and Xq pericentromeric region. X chromosome inactivation (XCI) studies demonstrated a skewed pattern suggesting that the ring X remained active, likely contributing to the observed clinical features of brain dysmyelination. We hypothesize that a prezygotic asymmetric crossing over within a loop formed during meiosis in an X chromosome with a paracentric inversion resulted in an intermediate dicentric chromosome. An uneven breakage of the dicentric chromosome in the early postzygotic period might have resulted in the formation of one cell line with the X chromosome carrying a terminal deletion and pericentromeric duplication of the short arm and the second cell line with the X chromosome carrying a complete deletion of Xp. The cell line carrying the deletion of Xp could have then stabilized through self-circularization and formation of the ring X chromosome.
Mol Cytogenet 2008 Jul 25
PMID:Mosaicism for r(X) and der(X)del(X)(p11.23)dup(X)(p11.21p11.22) provides insight into the possible mechanism of rearrangement. 1865 7

Cystinuria type I is an autosomal recessive disorder with an exclusively renal phenotype caused by inactivating mutations in SLC3A1. Recently 3 similar but distinct syndromes associated with cystinuria type I have been described: 2p21 deletion syndrome, Hypotonia-Cystinuria Syndrome (HCS) and atypical HCS. Genetic analysis indicated that these are recessive contiguous gene deletion syndromes which differ in the number of genes affected. Patients with HCS are missing both alleles of SLC3A1 and PREPL. In atypical HCS an additional gene (C2orf34) is deleted, and finally, in the 2p21 deletion syndrome the open reading frame of PPM1B is also disrupted. With the exception of SLC3A1, the gene products have not been fully characterized. The severity of the different syndromes reflects the number of genes which are deleted. HCS, a relatively mild syndrome, is characterised by cystinuria type I, generalised hypotonia at birth, growth retardation and minor facial dysmorphic features. On the other end of the spectrum is the 2p21 deletion syndrome, a severe syndrome with a number of additional features including a moderate to severe psychomotor retardation and a decrease in activity of the respiratory chain complexes I, III, IV and V. Finally, atypical HCS displays an intermediate phenotype comparable with classical HCS but associated with mild to moderate mental retardation and a decrease in activity of only the respiratory chain complex IV. This review will focus on the phenotypic similarities and differences observed in these syndromes. Furthermore, we speculate on the function of the gene products, based on the available data.
Curr Mol Med 2008 Sep
PMID:Multi-system disorder syndromes associated with cystinuria type I. 1878 61

Tyrosine hydroxylase (TH) deficiency is a rare autosomal recessive disorder mapped to chromosome 11p15.5. Its clinical expression varies with presentations as dopa-responsive dystonia (recessive Segawa's disease), dopa-responsive infantile parkinsonism, dopa-responsive spastic paraplegia, progressive infantile encephalopathy or dopa-non-responsive dystonia. We describe a 7-year-old boy with progressive infantile encephalopathy and non-responsiveness to dopamine. The patient demonstrated generalized hypotonia, pyramidal tract dysfunction and temperature instability after the second month of life. Dystonia, tremor and oculogyric crises complicated the clinical picture during the following months. Neurotransmitter analysis in CSF disclosed almost undetectable levels of HVA and MHPG, whereas serum prolactin was profoundly increased. Subsequent molecular analysis revealed homozygosity for a missense mutation (c.707T>C) in the TH gene. l-Dopa therapy in both high and low doses resulted in massive hyperkinesias, while substitution with selegiline exerted only a mild beneficial effect. Today, at the age of 7 years, the patient demonstrates severe developmental retardation with marked trunkal hypotonia, hypokinesia and occasionally dystonic and/or hyperkinetic crises. He is the third Greek patient with TH deficiency to be reported. Since all three patients carry the same pathogenetic mutation, a founder effect is suspected.
Mol Genet Metab 2009 May
PMID:Tyrosine hydroxylase deficiency with severe clinical course. 1928 9

4p Monosomy and 12p trisomy have been discussed and redefined along with recently reviewed chromosomal syndromes. 12p Trisomy syndrome is characterized by normal or increased birth weight, developmental delay with early hypotonia, psychomotor delay, and typical facial appearance. Most likely, the observed phenotypic variability depends on the type and extent of the associated partial monosomy. Partial deletions of the short arm of one chromosome 4 cause the Wolf-Hirschhorn syndrome (WHS). Affected patients present Greek helmet face, growth and mental retardation, hypotonia, and seizures. The combination of these characteristics constitutes the phenotypic core of WHS. We present a clinical and molecular cytogenetic characterization of a 4-year old mentally retarded girl with macrosomy, facial dysmorphisms, and epilepsy, in whom an unbalanced t(4;12)(p16.3;p13.3) translocation was detected, giving rise to partial 4p monosomy and partial 12p trisomy. Because the patient shows most of the phenotypic characteristics of 12p trisomy, this case could contribute to a better definition of the duplicate critical region that determines the phenotype of the 12p trisomy syndrome.
Genet Test Mol Biomarkers 2009 Apr
PMID:Trisomy 12p and monosomy 4p: phenotype-genotype correlation. 1937 4

A baby-girl with congenital deafness was admitted at the age of 8 weeks for lack of head control, truncal hypotonia and echodense kidneys. At the age of 10 weeks cranial MRI showed a normal brain structure, generalized mild hypomyelination but no lactate peak on (1)H MR spectroscopy. A combined defect of respiratory chain enzyme complexes I, III, IV and V and severe depletion of mitochondrial DNA was found in skeletal muscle tissue. Genetic analysis revealed a novel mutation c.368T>C (p.Phe123Ser) in the RRM2B gene in the expressed maternal allele. The paternal allele was present in genomic DNA, but was not expressed as mature mRNA.
Mol Genet Metab 2009 Nov
PMID:A novel mutation of the RRM2B gene in an infant with early fatal encephalomyopathy, central hypomyelination, and tubulopathy. 1961 83

Congenital disorders of glycosylation (CDG) are an expanding group of inherited disorders caused by defects in the N- or O-Glycosylation of proteins and lipids. Several CDG subtypes have been described so far, including CDG type Ih which is caused by a deficiency of the dolichyl-P-Glc:Glc(1)Man(9)GlcNAc(2)-PP-dolichyl alpha1,3-glucosyltransferase (hALG8). The defect leads to an accumulation of Dol-PP-GlcNAc(2)Man(9) and Dol-PP-GlcNAc(2)Man(9)Glc(1) in the endoplasmic reticulum of patients' fibroblasts that can be detected by analyzing the lipid-linked oligosaccharyl intermediates. Five patients with CDG-Ih have been described so far. The clinical presentation of four of these patients was severe with death in early infancy. In this report, we describe two mildly affected siblings with CDG-Ih caused by two novel mutations. While one mutation (c.1434delC) causes a frame shift resulting in a premature termination codon (p.485X), the point mutation of the other allele (c.845C>T, p.A282V) causes an amino acid replacement in a highly conserved region of the hALG8 gene. The two siblings show similar symptoms, including pseudo-gynecomastia, epicanthus, muscular hypotonia, mental retardation and ataxia, expanding the genetic and clinical spectrum of CDG-Ih.
Mol Genet Metab 2009 Nov
PMID:Novel ALG8 mutations expand the clinical spectrum of congenital disorder of glycosylation type Ih. 1964 40

Spermine is present in many organisms including animals, plants, some fungi, some archaea, and some bacteria. It is synthesized by spermine synthase, a highly specific aminopropyltransferase. This review describes spermine synthase structure, genetics, and function. Structural and biochemical studies reveal that human spermine synthase is an obligate dimer. Each monomer contains a C-terminal domain where the active site is located, a central linking domain that also forms the lid of the catalytic domain, and an N-terminal domain that is structurally very similar to S-adenosylmethionine decarboxylase. Gyro mice, which have an X-chromosomal deletion including the spermine synthase (SMS) gene, lack all spermine and have a greatly reduced size, sterility, deafness, neurological abnormalities, and a tendency to sudden death. Mutations in the human SMS lead to a rise in spermidine and reduction of spermine causing Snyder-Robinson syndrome, an X-linked recessive condition characterized by mental retardation, skeletal defects, hypotonia, and movement disorders.
Cell Mol Life Sci 2010 Jan
PMID:Spermine synthase. 1985 64

The phenotype of partial trisomy 9p includes global developmental delay, microcephaly, bulbous nose, downturned oral commissures, malformed ears, hypotonia, and severe cognitive and language disorders. We present a case report and a comparative review of clinical findings on this condition, focusing on speech-language development, cognitive abilities and swallowing evaluation. We suggest that oropharyngeal dysphagia should be further investigated, considering that pulmonary and nutritional disorders affect the survival and quality of life of the patient. As far as we know, this is the first study of a patient with partial trisomy 9p described with oropharyngeal dysphagia.
Genet Mol Res 2009 Sep 22
PMID:Oropharyngeal dysphagia and language delay in partial trisomy 9p: case report. 1986 32

Autism spectrum disorders have been associated with maternally derived duplications that involve the imprinted region on the proximal long arm of chromosome 15. Here we describe a boy with a chromosome 15 duplication arising from a 3:1 segregation error of a paternally derived translocation between chromosome 15q13.2 and chromosome 9q34.12, which led to trisomy of chromosome 15pter-q13.2 and 9q34.12-qter. Using array comparative genome hybridization, we localized the breakpoints on both chromosomes and sequence homology suggests that the translocation arose from non-allelic homologous recombination involving the low copy repeats on chromosome 15. The child manifests many characteristics of the maternally-derived duplication chromosome 15 phenotype including developmental delays with cognitive impairment, autism, hypotonia and facial dysmorphisms with nominal overlap of the most general symptoms found in duplications of chromosome 9q34. This case suggests that biallelically expressed genes on proximal 15q contribute to the idic(15) autism phenotype.
Mol Cytogenet 2009 Dec 18
PMID:Autistic disorder associated with a paternally derived unbalanced translocation leading to duplication of chromosome 15pter-q13.2: a case report. 2002 61


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>