Carnitine deficiency associated with ornithine transcarbamylase deficiency

An infant with X-linked recessive ornithine transcarbamylase deficiency is described who also had severe deficiency of plasma and liver carnitine during normoammonemic periods. Treatment with L-carnitine (100 mg/kg/day) for 12 months decreased the frequency of hospitalizations for hyperammonemia, although it did not alter his neurologic status. This report demonstrates that persistent carnitine deficiency may be present in patients with ornithine transcarbamylase deficiency even when plasma ammonia is normal. Carnitine evaluation and supplementation may be important in the treatment of patients with this metabolic disorder.     

Hyperammoniemic coma in an adolescent girl: An unusual case of ornithine transcarbamylase deficiency

Ornithine transcarbamylase deficiency (OTCD) is caused by an alteration of urea synthesis, linked with partial modification of the X-chromosome, whose clinical manifestations are: lethargy, nausea, vomiting and cerebral edema. While in newborn males OTCD presents with hyperammoniemia leading to cerebral palsy with profound neurological impairment and eventually death, in women who are healthy carriers, it is possible to detect the disorder only through specific tests, since heterozygote women are rarely symptomatic. We describe the case of a young woman admitted to the hospital after an episode of mental confusion with vomiting and psychomotor restlessness, which had previously occurred several times during the premenstruum and lasted a few hours. A 2 day history of stupor made admission mandatory. Tests carried out during the hospital stay showed marked hyperammoniemia and unconjugated hyperbilirubinemia, marked cerebral edema documented by a CT scan. Liver biopsy and CSF test were normal. Screening of plasma and urinary aminoacids, level of orotic acid in the urine and OTC activity in the liver, confirmed the diagnosis of OTCD. The possibility of early diagnosis and therapy of a disease which otherwise leads to death, emphasizes the importance of precise evaluation of a possible organic cause of anorexia and behaviour disorders in young women.

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Sommario Il deficit di ornitintranscarbamilasi (OTCD) è determinato da un'alterazione della sintesi di urea, legata ad una parziale modificazione del cromosoma X, le cui manifestazioni cliniche sono caratterizzate da sonnolenza, nausea, vomito, edema cerebrale. Mentre nei neonati maschi l'OTCD si manifesta con iperammoniemia seguita da paralisi cerebrale con importanti deficit neurologici ed eventualmente decesso, nelle donne, che sono portatrici sane, è possibile rilevare la malattia solo attraverso specifici tests, dato che le donne eterozigoti sono raramente sintomatiche. Gli Autori descrivono il caso di un'adolescente ricoverata dopo un episodio confusionale, nausea, vomito, irrequietezza psicomotoria, presentatosi diverse volte durante il periodo premestruale e protrattosi diverse ore. L'episodio attuale, perdurante da 2 giorni, portò al ricovero ospedaliero. I test eseguiti durante il ricovero evidenziarono marcata iperammoniemia e incremento della bilirubinemia indiretta, evidente edema cerebrale alla TAC cranio. La biopsia epatica e l'esame liquorale risultarono nella norma. Uno screening degli aminoacidi urinari e plasmatici, dell'acido orotico urinario e dell'attività epatica dell'OTC confermarono la diagnosi di OTCD. La possibilità di diagnosi precoce e di terapia per una malattia che altrimenti porta a morte, rileva l'importanza di una precisa valutazione di una possibile causa organica in giovani affette da anoressia e disturbi del comportamento.

     

Severe cerebral damage in ornithine transcarbamylase deficiency

Two patients are described with hyperammonemia due to ornithine transcarbamylase (OTC) deficiency who suffered severe shrinkage and collapse of the brain. The cerebral cortex was spongy and cavitated, containing only a few residual neurons, and was markedly gliosed. In one patient the basal ganglia were affected and harbored Alzheimer type II astrocytes. These lesions resemble those of acquired hepatocerebral degeneration and occur especially in female children with the milder form of the disease, who have a potential to survive. Strict observance of dietary restrictions is mandatory to avoid catastrophic damage to the brain.     

Electroencephalographic findings in ornithine transcarbamylase deficiency.

A 3-day-old infant presented with anorexia, irritability, hypotonia, and seizures. Blood ammonia was 2115 micromol/L and amino and organic acid analyses were consistent with ornithine transcarbamylase deficiency. Liver biopsy confirmed only 1% enzyme activity. The patient was treated with hemodialysis. An electroencephalogram (EEG) revealed multifocal independent spike-and-sharp-wave discharges. After initial stabilization he was placed on a low-protein diet with citrulline and phenylbutyrate. Conjugating agents (arginine, sodium benzoate, and sodium phenylacetate) have been added during periods of metabolic decompensation. Although developmentally delayed, the patient has shown signs of clinical improvement and EEG activity has likewise improved with only mild background slowing and no evidence of epileptogenic activity at 4 years of age. A second infant presented at 3 days of age with a similar history, blood ammonia of 1382 micromol/L, and metabolic studies indicative of ornithine transcarbamylase deficiency. EEG showed multifocal independent ictal and interictal discharges. Electrographic abnormalities persisted despite lowering of blood ammonia with hemodialysis and conjugating agents. The patient continued to decline clinically and died on the 7th hospital day. EEG changes parallel the clinical course of ornithine transcarbamylase deficiency and may serve as an objective marker of the effectiveness of therapeutic interventions.     

An autopsy case of ornithine transcarbamylase deficiency

We present an autopsy case of ornithine transcarbamylase (OTC) deficiency with grumose degeneration in the dentate nucleus of the cerebellum. The patient had intractable neonatal convulsions and hyperammonemia from the 3rd day after birth. Diagnosis of OTC deficiency was made based on null activity of the enzyme and four-base deletions in exon 9 of the OTC gene. Death was due to sepsis as well as disseminated intravascular coagulation at 1 year and 2 months of age. Neuropathology showed multiple cystic changes and ulegyria in the bilateral frontal and parietal lobes. Multiple cysts were associated with the region, which was infiltrated with macrophages surrounded by astroglia showing palisading pattern. Ferrugination was marked in the thalamus and severe neuronal loss with astrogliotic change in the CA1-2 area of the hippocampus. Grumose degeneration was noted in the dentate nucleus of the cerebellum. This is the first report of grumose degeneration in OTC deficiency.     

Magnetic resonance imaging in late-onset ornithine transcarbamylase deficiency

We examined brain magnetic resonance imaging (MRI) in a cohort of seven patients with ornithine transcarbamylase deficiency (OTCD), and correlated MRI findings with clinical manifestations. Seven patients with OTCD, aged 3-27 years, all with a missense mutation, were involved in the study. We classified the OTCD patients clinically into four stages. MR study was performed with a 1.5-T superconducting magnet during asymptomatic periods. MRI revealed white matter lesions in two patients with an advanced clinical stage, i.e. T1 and T2 prolongated round lesions in the deep white matter and posterolateral angle of the lateral ventricle in one patient; small foci of T2 and T1 prolongation in the subcortical white matter in another. Parenchymal lesions, and cerebral and cerebellar atrophy were not found in the other five patients. MRI might be normal in the early stage of the disease, and progress in proportion to the clinical stage of OTCD. OTCD should be considered as a differential diagnosis of small foci in the white matter in children.     

Distinctly abnormal brain metabolism in late-onset ornithine transcarbamylase deficiency

OBJECTIVE: To assess alterations in brain metabolites in patients with late-onset ornithine transcarbamylase deficiency (OTCD). METHODS: Six unrelated, asymptomatic Japanese late-onset OTCD patients were analyzed by proton MRS ((1)HMRS) using a point-resolved spectroscopy technique (repetition and echo times, 5000 and 30 ms). Localized spectra for the centrum semiovale were acquired and absolute metabolite concentrations were calculated using an LCModel. RESULTS: Compared with age-matched controls, N-acetylaspartate and creatine concentrations were normal in all patients. The glutamine (Gln) plus glutamate concentration was increased in four patients, which progressed in proportion to the clinical stage. myo-inositol (mI) could not be detected in five symptomatic patients. A decreased choline (Cho) concentration was detected in two clinically severe patients. (1)HMRS after liver transplantation in one patient revealed the normalization of all metabolites. CONCLUSION: These findings suggest progression of neurochemical events in OTCD, i.e., mI depletion and Gln accumulation followed by Cho depletion, which is reverse of that in hepatic encephalopathy, i.e., Cho depletion followed by mI depletion and Gln accumulation.     

Metabolic and neuropsychological phenotype in women heterozygous for ornithine transcarbamylase deficiency

We compared neurocognitive indices with clinical status, mutation analysis, and urea synthetic capacity in 19 women heterozygous for ornithine transcarbamylase deficiency. Although as a group, these women had average IQ scores, they displayed a specific neuropsychological phenotype with significant strengths in verbal intelligence, verbal learning, verbal memory, and reading, and significant weaknesses in fine motor dexterity/speed and nonsignificant weaknesses in nonverbal intelligence, visual memory, attention/executive skills, and math. This suggests selective vulnerability of white matter and better preservation of gray matter. When the group was divided into symptomatic and asymptomatic subgroups, based on either clinical history or residual urea synthetic capacity, the asymptomatic subgroup outperformed the symptomatic subgroup on all tested domains of neuropsychological functioning. Furthermore, the amount of residual urea synthetic capacity was predictive of several end point cognitive measures. There was no correlation between neonatal versus late-onset mutation or between normal or abnormal allopurinol challenge and neuropsychological outcome. In sum, we identified a specific metabolic and neurocognitive phenotype in women heterozygous for ornithine transcarbamylase deficiency. The findings support the importance of maintaining meticulous metabolic control in children with urea cycle disorders, because even mildly symptomatic subjects demonstrate cognitive deficits.     

Acute hemiparesis as the presenting sign in a heterozygote for ornithine transcarbamylase deficiency

Strokes in children occur in conjunction with cardiac disease, hematological disorders, trauma, intracranial infections and migraine. Recently several inborn errors of metabolism have been recognized as possible causes of stroke-like symptoms. We describe a female heterozygote of ornithine transcarbamylase deficiency, who presented with convulsions and right sided hemiplegia. MR-imaging of the brain demonstrated an acute ischemic lesion in the left hemisphere. In addition to other known metabolic causes of stroke like attacks urea cycle defects should be considered in the differential diagnosis of acute hemiplegia in childhood.     

Parieto-occipital encephalomalacia in neonatal hyperammonemia with ornithine transcarbamylase deficiency: A case report

Urea cycle disorders are congenital metabolic disorders that often cause episodic hyperammonemia. Neuroimaging in episodic hyperammonemia demonstrates several patterns of brain injuries, including focal lesions in the lentiform nucleus, insula, cingulate gyrus, and perirolandic fissure, as well as diffuse cerebral edema. In cases with neonatal onset of hyperammonemia, similar lesions have also been reported. We herein report a boy with severe neonatal hyperammonemia caused by ornithine transcarbamylase deficiency. He presented with parieto-occipital encephalomalacia, which resembles severe neonatal hypoglycemia on magnetic resonance imaging. This radiological finding may indicate parieto-occipital vulnerability not only to hypoglycemia but also to hyperammonemia.     

Hyperammonaemic encephalopathy after initiation of valproate therapy in unrecognised ornithine transcarbamylase deficiency

Ornithine transcarbamylase deficiency is an X linked disorderand the most common inherited cause of hyperammonaemia. Fluctuating concentrations of ammonia, glutamine, and otherexcitotoxic amino acids result in a chronic or episodically recurringencephalopathy. A heterozygous female patient first presented withprotein intolerance, attacks of vomiting, and signs of mentalretardation in early childhood. At the age of 16 complex partialseizures occurred which were treated with sodium valproate. Seven daysafter initiation of valproate therapy, she developed severehyperammonaemic encephalopathy with deep somnolence. The maximumconcentration of ammonia was 480 µmol/l. After withdrawal ofvalproate, three cycles of plasma dialysis, and initiation of aspecific therapy for the inborn metabolic disease, ammoniaconcentrations fell to normal values. The patient remitted, returningto her premorbid state. Valproate can cause high concentrations ofammonia in serum in patients with normal urea cycle enzymes and mayworsen a pre-existing hyperammonaemia caused by an enzymatic defect ofthe urea cycle. Sufficient diagnostic tests for the detection ofmetabolic disorders must be performed before prescribing valproate forpatients with a history of encephalopathy.

     

A case of ornithine transcarbamylase deficiency presenting severe symptoms in adulthood]

An adult female case of ornithine transcarbamylase (OTC) deficiency is presented in the following. The patient had had past episodes of drowsiness with a duration less than a few minutes several times a year during childhood. She suddenly became comatose at 25 years of age, and died after 13 months of persistent vegetative state. Blood chemistry showed hyperammonemia with no liver cirrhosis or portal-systemic shunt. Plasma amino acid analysis indicated elevated glutamate and glycine levels, and plasma levels of citrulline and arginine to be low. The urinary orotic acid level was high. OTC activity of a liver specimen was 65 percent of the normal level. This is a rare case demonstrating hyperglycinemia and an elevated level of serum OTC. The importance of ruling out defective ureagenesis in adults with disturbed consciousness should be emphasized.     

Late onset heterozygous ornithine transcarbamylase deficiency mimicking complex partial status epilepticus

A 57 year old woman with post-traumatic complex partial seizures was admitted because of recurrent episodes of altered mental state over the preceding 4 years, each lasting up to 5 days. There was a history of dietary protein intolerance since childhood and two of her daughters had died in the neonatal period from unexplained encephalopathies. In hospital she developed fluctuating confusion, amnesia, and sudden episodes of unresponsiveness. An EEG was consistent with complex partial status epilepticus but there was no response to benzodiazepines. Nasogastric feeding and sodium valproate were given and shortly afterwards she lapsed into a deep coma. Blood ammonia and urinary orotate were raised, and genetic testing confirmed that she was a carrier of a mutation in exon 3 of the ornithine transcarbamylase gene (C to T at position 92). Treatment with protein restriction, carnitine, and sodium phenylbutyrate led to a full recovery over a period of 3 months. To our knowledge this is the oldest age of onset yet described in a manifesting carrier. She is the fifth patient with heterozygous ornithine transcarbamylase deficiency reported to have had a severe reaction to sodium valproate. Hyperammonaemic encephalopathy should be considered in patients of any age who experience fluctuating confusion.     

Adult onset ornithine transcarbamylase deficiency: an unusual cause of semantic disorders

Ornithine transcarbamylase deficiency (OTCD) is the most common urea cycle disorder. This condition usually presents in neonates or children. This report describes the clinical case of a 21 year old woman who was diagnosed in adulthood during the course of an unexplained coma. After recovery from the coma, she presented very unusual neuropsychological disorders involving memory and the meaning of certain words, suggesting a semantic deficit. The discovery of OTCD in adulthood is rare and the neuropsychological consequences may be unique.     

A female case of ornithine transcarbamylase deficiency with marked computed tomographic abnormalities of the brain

The patient, 2 years and 9 months of age, was referred to our hospital with complaints of frequent vomiting, left hemiconvulsion and deep coma. The serum ammonia level was 251 micrograms/dl. Urine had a high orotate level (3,900 mumol/g creatinine). There was 7% residual of ornithine transcarbamylase (OTC) activity in the liver. Activities of other enzymes of the urea cycle were within normal limits. CT scanning on admission showed diffuse low density of both frontal lobes and of the right temporo-parietal lobe, narrowing of the right lateral ventricle and a shift of the mid-line to the left. The diffuse low density area was not enhanced after contrast medium injection. Follow-up CT scanning showed progressive bilateral ventricular dilatation and cerebral and cerebellar atrophy.