1/19. Xanthine stone in the urinary bladder of a male child.urinary tract calculi composed primarily of xanthine are rate both in adults and children. We describe the clinical presentation and management of a 3.5-year-old boy with hereditary xanthinuria (an autosomal recessive disorder of purine metabolism) and primary bladder calculus formed from xanthine. To our knowledge this case demonstrates a previously undescribed form of xanthinuria in childhood. Xanthine stones, although rare, should be considered in the diagnosis of urolithiasis.- - - - - - - - - - ranking = 1keywords = metabolism (Clic here for more details about this article) |
2/19. diagnosis of dihydropyrimidine dehydrogenase deficiency in a neonate with thymine-uraciluria.dihydropyrimidine dehydrogenase deficiency is an inborn error of pyrimidine metabolism characterised by thymine-uraciluria, convulsive disorders and developmental delay in paediatric patients, and an increased risk of toxicity from 5-fluorouracil treatment. This report is of the first patient with dihydropyrimidine dehydrogenase deficiency diagnosed in hong kong. The patient was a 2-day-old male neonate of Pakistani origin who presented with convulsions. diagnosis was made by gas chromatographic-mass spectrometric detection of thymine-uraciluria and by molecular detection of a G to A point mutation in a 5'-splicing site leading to skipping of exon 14 in the DPYD gene of chromosome location 1q22. The results showed that the patient and his mother were homozygous and the father heterozygous for the splice site mutation. The mother also had thymine-uraciluria but was clinically asymptomatic.- - - - - - - - - - ranking = 32.939333468163keywords = inborn error, metabolism, error (Clic here for more details about this article) |
3/19. beta-Ureidopropionase deficiency: an inborn error of pyrimidine degradation associated with neurological abnormalities.beta-Ureidopropionase deficiency is an inborn error of the pyrimidine degradation pathway, affecting the cleavage of N-carbamyl-beta-alanine and N-carbamyl-beta-aminoisobutyric acid. In this study, we report the elucidation of the genetic basis underlying a beta-ureidopropionase deficiency in four patients presenting with neurological abnormalities and strongly elevated levels of N-carbamyl-beta-alanine and N-carbamyl-beta-aminoisobutyric acid in plasma, cerebrospinal fluid and urine. No beta-ureidopropionase activity could be detected in a liver biopsy obtained from one of the patients, which reflected the complete absence of the beta-ureidopropionase protein. Analysis of the beta-ureidopropionase gene (UPB1) of these patients revealed the presence of two splice-site mutations (IVS1-2A>G and IVS8-1G>A) and one missense mutation (A85E). Heterologous expression of the mutant enzyme in escherichia coli showed that the A85E mutation resulted in a mutant beta-ureidopropionase enzyme without residual activity. Our results demonstrate that the N-carbamyl-beta-amino aciduria in these patients is due to a deficiency of beta-ureidopropionase, which is caused by mutations in the UPB1 gene. Furthermore, an altered homeostasis of beta-aminoisobutyric acid and/or increased oxidative stress might contribute to some of the clinical abnormalities encountered in patients with a beta-ureidopropionase deficiency. An analysis of the presence of the two splice site mutations and the missense mutation in 95 controls identified one individual who proved to be heterozygous for the IVS8-1G>A mutation. Thus, a beta-ureidopropionase deficiency might not be as rare as is generally considered.- - - - - - - - - - ranking = 159.69666734081keywords = inborn error, error (Clic here for more details about this article) |
4/19. dihydropyrimidine dehydrogenase deficiency presenting at birth.Dihydropyrimidine dehydrogenase (DPD) deficiency (McKusick 274270) is a clinically heterogeneous autosomal recessive disorder of pyrimidine metabolism. DPD is the enzyme that catalyses the first and the rate-limiting step in the catabolism of uracil, thymine and the analogue 5-fluorouracil. To date, more than 30 patients have been diagnosed with a complete enzyme deficiency. Here, we describe the fifth case with a complete DPD deficiency presenting at birth with severe neurological abnormalities. The patient was homozygous for the common splice-site mutation IVS14 1G > A.- - - - - - - - - - ranking = 1keywords = metabolism (Clic here for more details about this article) |
5/19. Beta-ureidopropionase deficiency presenting with febrile status epilepticus.Beta-ureidopropionase is the third enzyme in the catabolic pathway of uracil and thymine. To date, only three other patients are reported with this inborn error of metabolism. We report the clinical presentation of a male patient who presented at the age of 4 months after an ALTE-like event (ALTE = acute life-threatening event) with febrile status epilepticus. Such a clinical presentation has not been reported before in this condition. diagnosis was based on biochemical, enzymatic and molecular studies. MRI (magnetic resonance imaging) at the age of 11 months demonstrated large subdural hematomata and global supratentorial atrophy. At that time the patient showed severe psychomotor retardation with muscular hypotonia, extremely limited visual contact and poorly controlled epilepsy. CONCLUSIONS: Pyrimidine degradation defects should be included in the differential diagnosis of convulsions, (febrile) status epilepticus, psychomotor retardation and possibly also ALTE-like events.- - - - - - - - - - ranking = 32.939333468163keywords = inborn error, metabolism, error (Clic here for more details about this article) |
6/19. A neonate with recurrent vomiting and generalized hypotonia diagnosed with a deficiency of dihydropyrimidine dehydrogenase.Deficiency of dihydropyrimidine dehydrogenase (DPD) is a rare inborn error of pyrimidine metabolism. To date, only about 50 patients are known worldwide. The clinical picture is varied and is not yet fully described. Most patients are diagnosed at the age of 1-3 years. We present a patient diagnosed 8 weeks postpartum.The female patient presented in the first 3 days after birth with agitation, choking, and vomiting. Six weeks later, the patient presented again with vomiting and insufficient weight gain. Metabolic screening of urine showed a strongly increased excretion of uracil and thymine, with no other abnormalities. This suggested a deficiency of DPD which was confirmed by enzyme analysis in peripheral blood mononucleair (PBM) cells (patient: activity <0.01 nmol/mg/h; controls: 9.9 /- 2.8 nmol/mg/h). The patient was homozygous for the IVS14 1G>A mutation.MRI of the brain showed some cerebral atrophy; myelinization appeared normal. Many patients with DPD-deficiency suffer from convulsions and mental retardation, some show microcephaly, feeding difficulties, autism, and hypertonia. Our patient showed feeding difficulties and in the second half-year she developed slight motor retardation and generalized hypotonia. Further observation of the development of the patient may shed more light on the relationship between clinical symptoms and DPD deficiency. DPD deficiency may present in newborns with vomiting and hypotonia as the main symptoms.- - - - - - - - - - ranking = 32.939333468163keywords = inborn error, metabolism, error (Clic here for more details about this article) |
7/19. gout and neurological abnormalities associated with cardiomyopathy in a young man.A 21 year old man with a family history of gout and neurological deficits, developed severe idiopathic congestive cardiomyopathy after a long history of typical gouty attacks and neurological abnormalities. Clinical and laboratory evaluations showed borderline mental retardation, ataxia, sensorineural deafness, marked hyperuricaemia, and excessive uric acid excretion in the presence of impaired renal function. None of the known causes of cardiomyopathy was found. Even though red cell hypoxanthine guanine phosphoribosyltransferase enzyme activity was normal, this case probably represents an inborn error of purine metabolism. The association of cardiomyopathy with gout is very unusual. Previously it has been only once described in a single case.- - - - - - - - - - ranking = 32.939333468163keywords = inborn error, metabolism, error (Clic here for more details about this article) |
8/19. 2,8-Dihydroxyadenine urolithiasis: report of a case in a woman in the united states.Disorders of purine metabolism are well recognized clinical entities in modern medical practice. However, there are lesser known aberrations of purine and pyrimidine metabolism that can manifest as disease states. Deficiency of the enzyme adenine phosphoribosyltransferase is an autosomal recessive inherited disorder resulting in 2,8-dihydroxyadenuria, and possible urolithiasis and renal insufficiency. A woman with a pure 2,8-dihydroxyadenine ureteral calculus is reported, who represents the third reported case in the united states. Stones comprised of 2,8-dihydroxyadenine are difficult to distinguish from uric acid clinically, making sophisticated crystallographic analysis essential for accurate diagnosis. Treatment differs from that appropriate for uric acid lithiasis due to the limited solubility of 2,8-dihydroxyadenine at pH levels of less than 9. Prevention requires purine restriction and allopurinol.- - - - - - - - - - ranking = 2keywords = metabolism (Clic here for more details about this article) |
9/19. An inborn error of purine metabolism, deafness and neurodevelopmental abnormality.A syndrome of hyperuricemia, sensorineural deafness, mild mental handicap and congenital disequilibrium in a four-year-old boy is probably inherited as a sex-linked condition since his mother has sensorineural deafness and similar biochemical abnormalities. There is evidence of a superactive PP-ribose-P synthetase, normal purine salvage enzymes, and severe depletion of nicotinamide adenine dinucleotide and guanine triphosphate in red cells.- - - - - - - - - - ranking = 131.75733387265keywords = inborn error, metabolism, error (Clic here for more details about this article) |
10/19. molybdenum co-factor deficiency: an easily missed inborn error of metabolism.A female patient is described with combined deficiency of sulphite, zanthine and aldehyde oxidase. She presented at the age of four weeks with intractable seizures. Initially the diagnosis was suspected because of a very low serum urate level (23 mumol/1-1). This condition can be easily missed and it is proposed that measurement of serum urate be included in the metabolic assessment of neonates with unexplained seizures and developmental delay.- - - - - - - - - - ranking = 131.75733387265keywords = inborn error, metabolism, error (Clic here for more details about this article) |
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