O hiperinsulinismo (HI) é a causa mais comum de hipoglicemia, seja transitória ou permanente. de efeitos tóxicos da hiperamonemia nas crianças afetadas. Hipoglucemias por síndrome de hiperinsulinismo-hiperamonemia: a propósito de un caso diagnosticado en la edad adulta. Article. Dec Síndrome de hiperinsulinemia/hiperamonemia devido a uma mutação no gene da paciente de 6 anos de idade com hipoglicemia de jejum e hiperamonemia.
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Diagnosis should be considered in all infants with hyperinsulinemic hypoglycemia, and should motivate the determination of ammonia concentrations. Blood samples should be collected from a stasis-free vein into an EDTA evacuated tube, which must be immediately placed on ice and delivered to the lab as quickly as possible; plasma should be separated from the sample without delay, and ammonia analysis performed within 30 minutes.
Etiology Glutamate dehydrogenase GDH is a mitochondrial matrix enzyme that catalyzes the oxidative deamination of glutamate, yielding alpha-ketoglutarate and an ammonia by-product.
All the contents of this journal, except where otherwise noted, is licensed under a Creative Commons Attribution License. The child presented hypoglycemic episodes after overnight fasting, as well as in the postprandial period.
When these channels are closed, the cell depolarizes, enabling the opening of calcium channels, increased intracellular concentrations of this ion, and consequent release of insulin 4 Figure 2.
In this case, the administration of diazoxide causes opening of potassium channels which is normaland corrects hypoglycemia Figure 2 5. Presenting features of idiopathic ketotic hypoglycemia.
Urea synthesis from ammonia is carried out by the action of carbamoyl phosphate synthetase CPSan enzyme activated by N-acetylglutamate NAGwhich is decreased as a result of GDH overactivity 2,9. SRJ is a prestige metric based on the idea that not all citations are the same. Following demonstration of hyperinsulinemic hypoglycemia, an abdominal CT scan was carried out to exclude pancreatic neuroendocrine tumor NETand blood was collected to determine ammonia concentrations.
Direct sequencing of the coding hiperinsulunismo of the GLUD1 gene revealed that the affected child was heterozygous for a missense mutation in exon 11 c.
In the presence of activating mutations in the gene encoding GDH, there is a reduction in the sensitivity of the enzyme to allosteric inhibition by GTP and ATP, followed by increased response of GDH to leucine, increased deamination of glutamate, and consequent rise in ATP production, which causes excessive insulin secretion from beta cells in presence of glutamate and leucine.
Glutamate dehydrogenase GDH is a mitochondrial matrix enzyme that catalyzes the oxidative deamination of glutamate, yielding alpha-ketoglutarate and an ammonia by-product. The patient was found to be heterozygous for one de novo missense mutation c. The documents contained in this web site are presented for information purposes only. The child was delivered at term, with normal length and adequate weight for gestational age according to the parents exact data not availableand without perinatal complications.
Hiperamonemiia non cirrhotic adult hiperinsulinsmo. Inin a multicenter series of patients, hyperammonaemia was found in 12 out of 69 tested patients with hyperinsulinemic hypoglycemia Although the disease is rare, several case reports and some reviews have been published 2,9, Molecular mechanisms of neonatal hyperinsulinism. Initially, developmental milestones appeared to be normal the patient sat with support at the age of 5 months and walked at 14 monthsbut they were later compromised.
Subscriber If you already have your login data, please click here. HI-HA syndrome was first described in by Weinzimer and cols.
For all other comments, please send your remarks via contact us. Neurologic abnormalities appear to be unrelated to hypoglycemia. There are two basic mechanisms associated with abnormal increase of insulin secretion by the beta cells: Epilepsy and cognitive deficit that are unrelated to hypoglycemia may also occur.
Asymptomatic and persistent hyperammonemia about 3 to 5 times the normal range is observed. These mutations lead to constitutive closure of potassium channels, so that beta cell membranes remain continuously depolarized, allowing constant insulin secretion irrespective of intracellular concentrations of ATP. Neither parents carried this variant Figure 1suggesting a “de novo” mutation, which could not be definitively hjperamonemia because a paternity test was not performed.
Most patients are carriers of a de novo mutation, but some familial cases show autosomal dominant inheritance.
The material is in no way intended to replace professional medical care by a qualified specialist and should hiperinsuilnismo be used as a basis for diagnosis or treatment. December Pages ee22 Pages A syndrome of congenital hyperinsulinism and hyperammonemia. Children with HIHA frequently present seizures most commonly atypical or absence and learning difficulties.
Clinical description Clinical features are similar to those described in congenital isolated hyperinsulinism see this termbut the manifestations are milder with diagnosis delayed until late infancy. N Hiperamonemiq J Med.