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)

This report presents the first case where an infant with tetrahydrobiopterin deficiency has been identified by screening of newborns with hyperphenylalaninemia for tetrahydrobiopterin deficiency. Therapy with L-Dopa, 5-hydroxytryptophan, Carbidopa and tetrahydrobiopterin was started at the age of seven weeks while the child received a normal diet. At that time already muscular hypotonia was observed. The girl, now 2 1/2 years old, shows slight muscular hypotonia and hypomotility, short periods of hypertonic extension of the limbs, and retardation of sensomotor and mental development of about 6-8 months. Monotherapy with tetrahydrobiopterin dihydrochloride, 20-40 mg/kg b.w., diminished the muscular hypotonia. The effect lasted however for only about 1 day. While urinary serotonin and phenylalanine remained normal for at least 3 days and neopterin was only slightly elevated, urinary free dopamine however remained low. Similar results were obtained after 1',2'-diacetyl tetrahydrobiopterin dihydrochloride administration, 20 mg/kg b.w.
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PMID:Atypical phenylketonuria due to biopterin deficiency. Early treatment with tetrahydrobiopterin and neurotransmitter precursors, trials of monotherapy. 676 17

Autosomal recessive guanosine triphosphate cyclohydrolase (GTPCH) type I deficiency is characterized by complex neurological dysfunction. Patients are usually diagnosed with hyperphenylalaninemia in newborn screening. We describe two unrelated patients without hyperphenylalaninemia who presented during early infancy with severe motor retardation, hypokinesia, and truncal hypotonia. CSF homovanillic acid and 5-hydroxyindoleacetic acid as well as tetrahydrobiopterin and neopterin were decreased. Diagnosis of recessive GTPCH deficiency was confirmed biochemically, and a novel homozygous mutation was identified in one patient and a compound-heterozygous mutation of GCH1 in the other. Treatment with Levodopa/Carbidopa resulted in striking clinical improvement, with age-appropriate development at follow-up at 6 years. Autosomal recessive GTPCH deficiency should be considered in infants with severe truncal hypotonia even if hyperphenylalaninemia or classical extrapyramidal symptoms are missing. Neurotransmitter analysis followed by enzyme or mutation analysis can confirm the diagnosis, and Levodopa treatment should be started at high-doses.
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PMID:Clinical and biochemical characterization of patients with early infantile onset of autosomal recessive GTP cyclohydrolase I deficiency without hyperphenylalaninemia. 2081 8

We describe neurotransmitter abnormalities in two patients with drug-resistant epilepsy resulting from deleterious de novo mutations in sodium channel genes. Whole exome sequencing identified a de novo SCN2A splice-site mutation (c.2379+1G>A, p.Glu717Gly.fs*30) resulting in deletion of exon 14, in a 10-year old male with early onset global developmental delay, intermittent ataxia, autism, hypotonia, epileptic encephalopathy and cerebral/cerebellar atrophy. In the cerebrospinal fluid both homovanillic acid and 5-hydroxyindoleacetic acid were significantly decreased; extensive biochemical and genetic investigations ruled out primary neurotransmitter deficiencies and other known inborn errors of metabolism. In an 8-year old female with an early onset intractable epileptic encephalopathy, developmental regression, and progressive cerebellar atrophy, a previously unreported de novo missense mutation was identified in SCN8A (c.5615G>A; p.Arg1872Gln), affecting a highly conserved residue located in the C-terminal of the Nav1.6 protein. Aside from decreased homovanillic acid and 5-hydroxyindoleacetic acid, 5-methyltetrahydrofolate was also found to be low. We hypothesize that these channelopathies cause abnormal synaptic mono-amine metabolite secretion/uptake via impaired vesicular release and imbalance in electrochemical ion gradients, which in turn aggravate the seizures. Treatment with oral 5-hydroxytryptophan, l-Dopa/Carbidopa, and a dopa agonist resulted in mild improvement of seizure control in the male case, most likely via dopamine and serotonin receptor activated signal transduction and modulation of glutamatergic, GABA-ergic and glycinergic neurotransmission. Neurotransmitter analysis in other sodium channelopathy patients will help validate our findings, potentially yielding novel treatment opportunities.
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PMID:Secondary neurotransmitter deficiencies in epilepsy caused by voltage-gated sodium channelopathies: A potential treatment target? 2918 79