1/14. Human glycine decarboxylase gene (GLDC) and its highly conserved processed pseudogene (psiGLDC): their structure and expression, and the identification of a large deletion in a family with nonketotic hyperglycinemia.Mutations in the glycine decarboxylase gene (GLDC) cause nonketotic hyperglycinemia (NKH), an in-born error of metabolism characterized by severe neurological disturbance. We have determined the structure of GLDC and of its pseudogene (psiGLDC) and studied their expression for a molecular analysis of NKH. The GLDC gene spans at least 135 kb and consists of 25 exons. All donor and acceptor sites adhere to the canonical GT-AG rule, except for the donor site of intron 21, where a variant form GC is used instead of GT. The transcription initiation site has been assigned to a residue 163 bp upstream from the translation initiation triplet by primer extension analysis. The psiGLDC gene has no intron and shares 97.5% homology with the coding region of functional GLDC, suggesting that psiGLDC is a processed pseudogene that arose from the GLDC transcript about 4-8 million years ago. RNA blotting analysis has revealed that GLDC is expressed in human liver, kidney, brain, and placenta. We have also examined a patient with NKH with no detectable GLDC mRNA in his lymphoblasts. exons 1-3 of the functional GLDC gene from this patient are not amplified by polymerase chain reaction (PCR), whereas those from control subjects are. These results suggest a large homozygous deletion (at least 30 kb) in the patient. Furthermore, we have devised a semi-quantitative PCR to estimate the number of GLDC alleles by using psiGLDC as an internal control and have confirmed the homozygosity and heterozygosity of the deletion in the patient and his parents, respectively. Structural information of GLDC and psiGLDC should facilitate the molecular analysis of NKH.- - - - - - - - - - ranking = 1keywords = brain (Clic here for more details about this article) |
2/14. In vivo 1H magnetic resonance spectroscopic measurement of brain glycine levels in nonketotic hyperglycinemia.Nonketotic hyperglycinemia (NKH) is an autosomal recessive disorder of glycine metabolism. Defective glycine cleavage causes elevated concentrations of glycine in plasma, urine, and cerebrospinal fluid. A longitudinal study using magnetic resonance imaging (MRI) and single-voxel 1H magnetic resonance spectroscopy (MRS) was performed on an infant with the typical clinical picture of NKH. He was examined twice during the course of treatment with sodium benzoate and dextromethorphan. At the age of 10 months, MRI showed normal brain structure, while MRS detected a prominent glycine peak in the brain. Repeat MRS at the age of 13 months showed a small increase in glycine peak and a prominent glutamate/glutamine peak not previously detected. The MRS measurements were consistent with the slight increase in blood glycine level and the elevation in glutamine level, indicating that 1HMRS can be a valuable tool in the diagnosis and monitoring of treatment effects in patients with NKH.- - - - - - - - - - ranking = 6keywords = brain (Clic here for more details about this article) |
3/14. MRI in nonketotic hyperglycinaemia: case report.We present a girl with proven nonketotic hyperglycinaemia. The pathological findings on MRI were brain atrophy with thinning of the corpus callosum and delayed myelination of the cerebral hemispheres, particularly the parietal lobes.- - - - - - - - - - ranking = 1keywords = brain (Clic here for more details about this article) |
4/14. Localized proton MR spectroscopic detection of nonketotic hyperglycinemia in an infant.Nonketotic hyperglycinemia (NKH) is a rare metabolic brain disease caused by deficient activity of the glycine cleavage system. Localized proton MR spectroscopy (echo-time 166 msec), performed in an infant with the typical clinical and biochemical features of neonatal NKH, showed a markedly increased peak intensity at 3.55 ppm, which was assigned to glycine. Serial proton MR spectroscopic studies indicated that glycine/choline and glycine/total creatine ratios correlated closely with the patient's clinical course. Proton MR spectroscopy was useful for the non-invasive detection and monitoring of cerebral glycine levels in this infant with NKH.- - - - - - - - - - ranking = 1keywords = brain (Clic here for more details about this article) |
5/14. reflex seizures and non-ketotic hyperglycemia: an unresolved issue.reflex seizures are a rare form of epilepsy, the pathogenesis of which is unclear. They have been reported in the setting of non-ketotic hyperglycemia (NKH) and are considered to be neuroendocrine in origin. We report a diabetic patient with movement-induced seizures whose presentation suggests that brain ischemia may be the precipitating event in focal seizures seen in the setting of NKH. We recommend that in such instances a focal lesion such as stroke should be ruled out.- - - - - - - - - - ranking = 1keywords = brain (Clic here for more details about this article) |
6/14. prenatal diagnosis of hypoplasia of the corpus callosum in association with non-ketotic hyperglycinemia.Abnormalities of the corpus callosum are often associated with a poor prognosis due to the anatomical defect itself and associated anomalies that include malformations and inherited metabolic disorders. We report a case of the prenatal diagnosis of hypoplasia of the corpus callosum that was associated with non-ketotic hyperglycinemia. Metabolic disorders are a known association with corpus callosum abnormalities and carry a dismal prognosis. A diagnosis of non-ketotic hyperglycinemia should be considered when a fetus presents with an abnormality of the corpus callosum. A literature search reviews other inherited diseases associated with hypoplasia of the corpus callosum.- - - - - - - - - - ranking = 568.39664035941keywords = metabolic disorder (Clic here for more details about this article) |
7/14. Diffusion-weighted MR imaging in neonatal nonketotic hyperglycinemia.To our knowledge, we are the first to report the diffusion-weighted MR imaging findings in a 15-day-old neonate with nonketotic hyperglycinemia. We found bilaterally symmetrical lesions of restricted diffusion in the dorsal brain stem, cerebral peduncles, and posterior limbs of the internal capsule, which were more conspicuous and extensive on diffusion-weighted MR images than on T2-weighted images. These lesions are in the myelinated tracts of the neonate and are compatible with the expected sites of abnormality in vacuolating myelinopathy.- - - - - - - - - - ranking = 1keywords = brain (Clic here for more details about this article) |
8/14. Nonketotic hyperglycinemia: diffusion magnetic resonance imaging findings.We report about a boy with nonketotic hyperglycinemia who was studied at 15 days of life with a follow-up examination at age 6 months. Magnetic resonance (MR) imaging revealed progressive atrophy, callosal thinning, and delayed myelination. glycine peaks were shown by proton MR spectroscopy at 3.56 ppm with a long echo time (TE, 135 milliseconds; TR, 1500 milliseconds). Echo-planar diffusion MR imaging (TR, 5700 milliseconds; TE, 139 milliseconds) at 15 days of life revealed high-signal lesions in the pyramidal tracts, middle cerebellar pedicles, and dentate nuclei on b = 1000 s/mm2 images associated with low apparent diffusion coefficient (ADC) values. By age 6 months, the lesions became more prominent on b = 1000 s/mm2 images with lower ADC values. Diffusion MR imaging findings likely reflected the histopathologic changes of the disease which consisted of spongiosis of the myelinated brain tissue due to myelin vacuolation.- - - - - - - - - - ranking = 1keywords = brain (Clic here for more details about this article) |
9/14. Nonketotic hyperglycinemia in two siblings with neonatal seizures.seizures are a common problem in neonates. Differential diagnoses include infection, trauma, hypoxia and congenital metabolic disorders. Among these, congenital metabolic disorder is less familiar to general pediatricians. We report two patients with nonketotic hyperglycinemia (NKH), a rare and lethal congenital metabolic disease. Transient hyperammonemia and transient hypouricemia, uncommon features found in NKH, were detected in one patient. High doses of sodium benzoate and dextromethorphan failed to modify the clinical course. Neuropathology denoted characteristic diffuse vacuolization and changes in reactive and gliotic astrocytes. The clinical course, biochemical findings, diagnostic approaches and diagnostic tests are discussed in detail. Recent modalities of treatment are reviewed. Because of its rarity and rapidly progressive course, it maybe underdiagnosed resulting in death before being recognized. awareness of the possibility of congenital metabolic disorder in early neonatal catastrophe will increase the diagnostic rate.- - - - - - - - - - ranking = 1705.1899210782keywords = metabolic disorder (Clic here for more details about this article) |
10/14. Transient homonymous hemianopia and positive visual phenomena in nonketotic hyperglycemic patients.PURPOSE: To report a case of a transient homonymous hemianopia in a patient with nonketotic hyperglycemia with negative magnetic resonance imaging (MRI) scans. DESIGN: Case report. METHOD: A 72-year-old woman with diabetes mellitus was referred to the neuro-ophthalmology service with hyperglycemia and multiple visual complaints. RESULTS: The patient was found to have a dense left homonymous hemianopia on examination. An MRI scan of the brain was negative for a lesion affecting the visual pathways. Resolution of the homonymous hemianopia and the patient's symptoms came with normalization of her blood glucose levels. CONCLUSION: Nonketotic hyperglycemia is an important diagnostic consideration in patients who present with homonymous visual field defects but have negative neuroimaging studies.- - - - - - - - - - ranking = 1keywords = brain (Clic here for more details about this article) |
| | Next -> |