Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0027066 (myoclonus)
 4,275 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A deficiency of dihydrobiopterin synthesis was found in a 27-year-old man with mild mental retardation, rigid spasticity, hyperreflexia, dystonia, myoclonus, and delay in the initiation of action, since age 10. Symptoms improved after sleep. Urine contained large amounts of neopterin and a trace of biopterin. Dihydropteridine reductase activity in red blood cells was normal. CSF levels of HVA and 5-HIAA were low. Tetrahydrobiopterin administration lowered serum phenylalanine and improved the symptoms.
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PMID:Dihydrobiopterin synthesis defect: an adult with diurnal fluctuation of symptoms. 243 82

Tetrahydrobiopterin (BH4) deficiencies are a heterogeneous group of disorders caused by a defect in two of the three enzymes involved in its biosynthesis or in the two recycling enzymes. Except for the deficiency of dehydratase, an enzyme catalyzing a reaction in the recycling pathway, all other variants of BH4 deficiency are characterized by developmental delay, progressive neurological deterioration, hypokinesis, drooling, swallowing difficulty, truncal hypotonia, increased limb tone, myoclonus and brisk deep tendon reflexes. A deficiency of guanosine triphosphate cyclohydrolase I (GTPCH), the first enzyme in the biosynthetic pathway of BH4, is described in a 14-month-old male infant with hyperphenylalaninemia, developmental delay, hypertonia of the extremities, seizures, feeding difficulties, and vomiting. Urinary pteridine screening revealed very low levels of neopterin and biopterin which was highly suggestive of GTPCH deficiency. Low cerebrospinal fluid concentrations of 5-hydroxyindoleacetic acid (5HIAA) and homovanillic acid concentrations, together with no detectable neopterin and decreased concentrations of biopterin and folate, agreed with the diagnosis of GTPCH deficiency. Subsequently measured neopterin and biopterin synthesis in cytokine-stimulated skin fibroblasts confirmed GTPCH deficiency, albeit indirectly. The patient showed marked improvement on a low-protein low-phenylalanine diet with neurotransmitter precursor administration. The favorable outcome in this patient clearly shows that not only newborns with elevated phenylalanine levels but also older children with neurological signs and symptoms should be screened for a BH4 deficiency in order to have maximum benefit of the treatment.
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PMID:Guanosine triphosphate cyclohydrolase I deficiency: a rare cause of hyperphenylalaninemia. 1077 Jun 63

To evaluate cellular immune activation in opsoclonus-myoclonus syndrome, we measured the inflammatory marker neopterin in the cerebrospinal fluid of 16 children with opsoclonus-myoclonus and neuroblastoma, 24 children with opsoclonus-myoclonus but no tumor, and 19 age-matched controls. The mean concentration in opsoclonus-myoclonus was 2.3-fold higher than in controls (P = .008). Neopterin was greatly elevated in four of the most neurologically severe cases, up to 8.3-fold above the highest control level. Thirteen of the 40 children with opsoclonus-myoclonus but no controls had a neopterin concentration >2 SD above the control mean (P = .005). In this high neopterin subgroup, neurologic severity was significantly greater and the duration of neurologic symptoms was less. In 16 children re-examined on immunotherapy, including adrenocorticotropic hormone (ACTH) combination therapy, treatment was associated with a significant reduction in both neopterin and neurologic severity. Neopterin did not differ significantly between the tumor and non-tumor opsoclonus-myoclonus etiologies. No abnormalities of tetrahydrobiopterin were found. Although cerebrospinal fluid neopterin lacked the sensitivity to be a biomarker of disease activity in opsoclonus-myoclonus, elevated concentrations do support a role for T-cell activation and cell-mediated immunity in its pathophysiology.
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PMID:Evidence of cellular immune activation in children with opsoclonus-myoclonus: cerebrospinal fluid neopterin. 1570 63