Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0028738 (nystagmus)
 7,431 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Deoxyguanosine kinase (DGUOK) deficiency is the commonest type of mitochondrial DNA depletion associated with a hepatocerebral phenotype. In this article, we evaluate predictors of survival and therapeutic options in patients with DGUOK deficiency. A systematic search of MEDLINE, LILAC, and SCIELO was carried out to identify peer-reviewed clinical trials, randomized controlled trials, meta-analyses, and other studies with clinical pertinence. DGUOK deficiency was searched with the terms dGK, DGUOK, mitochondrial DNA depletion, mtDNA, and hepatocerebral. Bibliographies of identified articles were reviewed for additional references. Thirteen identified studies met the inclusion criteria and were used in this study. The analysis revealed that DGUOK deficiency is associated with a variable clinical phenotype. Long-term survival is best predicted by the absence of profound hypotonia, significant psychomotor retardation, or nystagmus. In the presence of these features, there is increased mortality, and liver transplantation does not confer increased survival. In summary, liver transplantation appears to be futile in the presence of specific neurological signs or symptoms in patients affected with DGUOK deficiency. Conversely, in the absence of these neurological features, liver transplantation may be considered a potential treatment.
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PMID:Abnormal neurological features predict poor survival and should preclude liver transplantation in patients with deoxyguanosine kinase deficiency. 1882 6

Deoxyguanosine kinase (DGUOK) catalyzes the first step of the mitochondrial deoxypurine salvage pathway, the phosphorylation of purine deoxyribonucleosides. Mutations in the DGUOK gene have been linked to inherited mtDNA depletion syndromes, neonatal liver failure, nystagmus, and hypotonia. Previously, we reported the first case of a heterozygous unclassified c.592-4_c.592-3delTT alteration in a patient with DGUOK deficiency without the demonstration of its pathogenicity (Dimmock et al., 2008). This alteration was predicted to cause aberrant splicing based upon two computer algorithms. We now report a homozygous c.592-4_c.592-3delTT mutation found in two affected siblings of asymptomatic consanguineous parents. The proband presented with symptoms of idiopathic hepatitis, liver dysfunction, nystagmus, and retinal blindness. This individual died at 6months of age due to liver failure. This individual's affected sibling presented similarly and has remarkable elevations of tyrosine, methionine, and alanine. Many organic acids were elevated in urine, including lactic acid, Krebs cycle intermediates, and para-hydroxy compounds; ketone bodies were also present. RNA studies support aberrant splicing. Sequencing of cDNA detected exon 5 skipping in the two affected siblings, but not in the normal control. These results indicate that the homozygous c.592-4_c.592-3delTT is deleterious and responsible for the DGUOK deficiency. The parents were subsequently confirmed to be carriers of this mutation. In summary, we have demonstrated that c.592-4_c.592-3delTT is a pathogenic splice acceptor site mutation leading to DGUOK deficiency.
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PMID:A novel c.592-4_c.592-3delTT mutation in DGUOK gene causes exon skipping. 1990 May 89

Deoxyguanosine kinase (DGUOK) catalyzes the first step of the mitochondrial deoxypurine salvage pathway, the phosphorylation of purine deoxyribonucleosides. Mutations in the DGUOK gene have been linked to inherited mitochondrial (mt)DNA depletion syndromes, neonatal liver failure, nystagmus, and hypotonia. We now report a novel homozygous c.34C > T (p.Arg12X) mutation found in an affected newborn of asymptomatic consanguineous parents. Respiratory distress started in the first hours after birth. The patient died at the age of 42 days due to liver failure. This genotype, which is to be expected for a homozygous stop codon mutation in exon 1, is associated with a severe clinical presentation.
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PMID:A novel mutation in the DGUOK gene in a Turkish newborn with mitochondrial depletion syndrome. 2153 44

Deoxyguanosine kinase (dGK) deficiency, a rare severe cause of mitochondrial DNA (mtDNA) depletion, has two forms of presentation: hepatocerebral syndrome and isolated hepatic disease. The authors report three cases with neonatal liver failure due to dGK deficiency. Consanguinity was present in all patients. One patient had a brother who died with a probable diagnosis of neonatal haemochromatosis. All patients had progressive cholestatic liver failure, hypoglycaemia, hyperlactacidaemia, elevated ferritin levels and nystagmus, since first day of life. Liver tissue study revealed: cholestasis, iron deposits, microvesicular steatosis and fibrosis/cirrhosis. Only one patient was submitted to liver transplantation. The other two died, at 2 and 5 months of age. mtDNA quantification and DGUOK gene study should be considered in infants/neonates with acute liver failure and systematically performed in patients with hepatocerebral presentation. Differential diagnosis with neonatal haemochromatosis is needed. Liver transplantation might be a therapeutic option. Early diagnosis is important for genetic counselling.
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PMID:Neonatal liver failure due to deoxyguanosine kinase deficiency. 2260 37

Deoxyguanosine kinase (DGUOK) (MIM#601465) deficiency was originally described as the cause of an infantile onset hepatocerebral mitochondrial disease [1]. The classic features of this disorder include significant hepatic failure with nystagmus and hypotonia. Mitochondrial DNA studies reveal significant mitochondrial DNA depletion in the affected tissues. Subsequently it has been shown that the same mutations in this gene may present with isolated acute liver failure without cerebral involvement. In this paper we studied the mitochondrial DNA depletion in cells from a patient presenting with mitochondrial myopathy caused by a novel mutation in DGUOK. Subsequently we developed the method to diagnose this condition using MyoD induced fibroblasts to study the muscle specific phenotype. In addition, supplementation of MyoD induced fibroblasts with dAMP and dGMP resulted in a restoration of mtDNA quantity.
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PMID:Recessive deoxyguanosine kinase deficiency causes juvenile onset mitochondrial myopathy. 2262 27