Acute Encephalopathic Crisis Research Articles

Phenotypic prediction in glutaric aciduria type 1 combining in silico and in vitro modeling with real-world data.

Glutaric aciduria type 1 (GA1) is caused by inherited deficiency of glutaryl-CoA dehydrogenase (GCDH). To further understand the unclear genotype-phenotype correlation, we transfected mutated GCDH into COS-7 cells resembling known biallelic GCDH variants of 47 individuals with GA1. In total, we modeled 36 genotypes with 32 missense variants. Spectrophotometry demonstrated an inverse correlation between residual enzyme activity and the urinary concentration of glutaric acid and 3-hydroxyglutaric acid, confirming previous studies (Pearson correlation, r = -0.34 and r = -0.49, p = 0.045 and p = 0.002, respectively). In silico modeling predicted high pathogenicity for all genotypes, which caused a low enzyme activity. Western blotting revealed a 2.6-times higher GCDH protein amount in patients with an acute encephalopathic crisis (t-test, p = 0.015), and high protein expression correlated with high in silico protein stability (Pearson correlation, r = -0.42, p = 0.011). The protein amount was not correlated with the enzyme activity (Pearson correlation, r = 0.09, p = 0.59). To further assess protein stability, proteolysis was performed, showing that the p.Arg88Cys variant stabilized a heterozygous less stable variant. We conclude that an integration of different data sources helps to predict the complex clinical phenotype in individuals with GA1.

2-Methylglutaconic acid as a biomarker in routine urine organic acids leading to the diagnosis of glutaric acidemia type I in a low excretor

GA1 (OMIM# 231670) is an organic aciduria caused by defective Glutaryl-CoA dehydrogenase (GCDH), encoded by GCDH. Early detection of GA1 is crucial to prevent patients from developing acute encephalopathic crisis and subsequent neurologic sequelae. Diagnosis of GA1 relies on elevated glutarylcarnitine (C5DC) in plasma acylcarnitine analysis and hyperexcretion of glutaric acid (GA) and 3-hydroxyglutaric acid (3HG) in urine organic acid (UOA) analysis. Low excretors (LE), however, exhibit subtly elevated or even normal plasma C5DC and urinary GA levels, leading to screening and diagnostic challenges. The measurement of 3HG in UOA is thus often used as the 1st tier test for GA1. We described a case of LE detected via newborn screen with normal excretion of GA, absent of 3HG and increased 2-methylglutaconic acid (2MGA), which was detected at 3mg/g creatinine (reference interval<1mg/g creatinine) without appreciable ketones. We retrospectively examined UOA of 8 other GA1 patients and the 2MGA level ranged from 2.5 to 27.39mg/g creatinine, which is significantly higher than normal controls (0.05-1.61mg/g creatinine). Although the underlying mechanism of 2MGA formation in GA1 is unclear, our study suggests 2MGA is a biomarker for GA1 and should be monitored by routine UOA to evaluate its diagnostic and prognostic value.

Treatment of glutaric aciduria type I (GA-I) via intracerebroventricular delivery of GCDH

Glutaric aciduria type I (GA-I) is an autosomal recessive genetic disorder caused by a deficiency in glutaryl-CoA dehydrogenase (GCDH). Patients who do not receive proper treatment may die from acute encephalopathic crisis. Current treatments for GA-I include a low-lysine diet combined with oral supplementation of L-carnitine. A mouse model of Gcdhc.422_428del/c.422_428del (Gcdh−/−) was generated in our laboratory using CRISPR/Cas9. Gcdh−/− mice had significantly higher levels of glutaric acid (GA) in the plasma, liver, and brain than those in wild-type C57BL/6 mice. When given a high-protein diet (HPD) for two days, approximately 60% of Gcdh−/− mice did not survive the metabolic stress. To evaluate whether GCDH gene replacement therapy could be used to provide sustained treatment for patients with GA-1, we prepared a recombinant adeno-associated virus (rAAV) carrying a human GCDH expression cassette and injected it into Gcdh−/− neonates for a proof-of-concept (PoC) study. Our study demonstrated that delivering rAAV to the central nervous system (CNS), but not the peripheral system, significantly increased the survival rate under HPD exposure. Our study also demonstrated that rAAVPHP.eB mediated a higher efficiency than that of rAAV9 in increasing the survival rate. Surviving mice showed dose-dependent GCDH protein expression in the CNS and downregulation of GA levels. Our study demonstrated that AAV-based gene replacement therapy was effective for GA-I treatment and provided a feasible solution for this unmet medical need.

Does glutaric aciduria type 1 affect hearing function?

This study aimed to evaluate audiological findings among patients with glutaric aciduria type 1 (GA-1). We used a large test battery for the audiological evaluation of 17 individuals with GA-1 (the study group) and 20 healthy individuals (the control group). Conventional audiometry (0.125-8kHz), distortion product otoacoustic emissions (DPOAEs) (1, 1.5, 2, 3, 4, 6, and 8kHz), contralateral suppression of otoacoustic emissions, and auditory brainstem response (ABR) ( 30, 50, 70 and 90 dB nHL) were measured for all participants (n = 37). Mild sensorineural hearing loss was found in 77.47% (n = 13) of the patients with GA-1, and normal hearing thresholds were seen in 23.53% (n = 4). There were three asymptomatic patients at the time of diagnosis [two developed mild mental motor retardation (MMR) and one developed severe MMR during the follow-up], one with a normal hearing threshold and two with mild hearing loss), and 14 symptomatic patients (three with normal hearing thresholds and 11 with mild hearing loss). Seven of the symptomatic patients diagnosed following an encephalopathic crisis required intensive care and showed significantly worse hearing thresholds than those without symptoms [20.86 ± 4.47 vs. 15.44 ± 3.96 decibel hearing level (dB HL), p = 0.039*], while five had mild-to-moderate hearing loss. Acute encephalopathic crisis had a negative effect on hearing function in the symptomatic patients. The emission and contralateral suppression amplitude values of the study group were significantly lower compared to the control group (p < 0.05). The I-V interpeak latency and absolute latencies of ABR waves I, III, and V of the study group were observed to be significantly prolonged and morphologically distorted compared to those of the control group (p < 0.05). Five patients had MMR, and three had moderate MMR; all eight had mild-to-moderate hearing loss. In addition, of the eight patients with mild MMR, four had mild hearing loss. In particular, the morphological findings of ABR waves were significantly worse in the patients with severe and moderate MMR (p < 0.05). There was a significant correlation between a macrocephaly history (12 patients) and hearing loss (p = 0.041*). Magnetic resonance imaging findings were evaluated in all the 17 patients with GA-1, and typical fronto-temporal atrophy and sylvian fissure enlargement were observed. Our findings support that GA-1 is associated with auditory impairment, primarily in symptomatic patients. Adequate audiological test battery evaluation is essential in this context, particularly for symptomatic patients with a history of encephalopathic crises.

GLUTARIC ACIDEMIA TYPE 1: A CASE REPORT FROM PAKISTAN

INTRODUCTION: Glutaric aciduria type 1 is a neurometabolic disorder occurring due to deficient activity of glutaryl-CoA dehydrogenase. Multiple neurotoxic metabolites start accumulating in plasma, CSF and urine which are detected by mass spectrometry. Early new-born screening plays an important role in early diagnosis whereas typical radiographic features and metabolic workup supports the diagnosis. Treatment guidelines have been constructed to prevent acute encephalopathic crisis and remove neurotoxic metabolites from plasma to prevent brain damage, the goal of treatment. CASE PRESENTATION: An eight month old male patient presented with fever, seizures and altered level of consciousness. He was macrocephalic with examination findings suggestive of upper motor neuron lesion. The typical radiologic features suggestive of glutaric aciduria type 1 were noticed in neuroimaging. Workup for inborn error of metabolism confirmed the same. Early treatment was started keeping a metabolic disease consultant on board. The patient was safely discharged from hospital after stabilization and is well till date. CONCLUSION: This case is being reported to emphasize the importance of early diagnosis, timely management and adherence to proper treatment in paediatric patients presenting with metabolic crisis. This can help prevent irreversible damage in patients especially in the ones diagnosed as glutaric aciduria type 1.

Organic Acidemias.

Organic Acidemias.

Glutaric Aciduria Type I Missed by Newborn Screening: Report of Four Cases from Three Families.

Glutaric aciduria type I (GA-1) is a rare autosomal-recessive disorder of the degradation of the amino acids lysine and tryptophan caused by mutations of the GCDH gene encoding glutaryl-CoA-dehydrogenase. Newborn screening (NBS) for this condition is based on elevated levels of glutarylcarnitine (C5DC) in dried blood spots (DBS). Here we report four cases from three families in whom a correctly performed NBS did not detect the condition. Glutarylcarnitine concentrations were either normal (slightly below) or slightly above the cut-off. Ratios to other acylcarnitines were also not persistently elevated. Therefore, three cases were defined as screen negative, and one case was defined as normal, after a normal control DBS sample. One patient was diagnosed after an acute encephalopathic crisis, and the other three patients had an insidious onset of the disease. GA-1 was genetically confirmed in all cases. Despite extensive efforts to increase sensitivity and specificity of NBS for GA-1, by adjusting cut-offs and introducing various ratios, the biological diversity still leads to false-negative NBS results for GA-1.

The first knock-in rat model for glutaric aciduria type I allows further insights into pathophysiology in brain and periphery

Glutaric aciduria type I (GA-I, OMIM # 231670) is an inborn error of metabolism caused by a deficiency of glutaryl-CoA dehydrogenase (GCDH). Patients develop acute encephalopathic crises (AEC) with striatal injury most often triggered by catabolic stress. The pathophysiology of GA-I, particularly in brain, is still not fully understood.We generated the first knock-in rat model for GA-I by introduction of the mutation p.R411W, the rat sequence homologue of the most common Caucasian mutation p.R402W, into the Gcdh gene of Sprague Dawley rats by CRISPR/CAS9 technology. Homozygous Gcdhki/ki rats revealed a high excretor phenotype, but did not present any signs of AEC under normal diet (ND). Exposure to a high lysine diet (HLD, 4.7%) after weaning resulted in clinical and biochemical signs of AEC.A significant increase of plasmatic ammonium concentrations was found in Gcdhki/ki rats under HLD, accompanied by a decrease of urea concentrations and a concomitant increase of arginine excretion. This might indicate an inhibition of the urea cycle. Gcdhki/ki rats exposed to HLD showed highly diminished food intake resulting in severely decreased weight gain and moderate reduction of body mass index (BMI). This constellation suggests a loss of appetite. Under HLD, pipecolic acid increased significantly in cerebral and extra-cerebral liquids and tissues of Gcdhki/ki rats, but not in WT rats. It seems that Gcdhki/ki rats under HLD activate the pipecolate pathway for lysine degradation. Gcdhki/ki rat brains revealed depletion of free carnitine, microglial activation, astroglyosis, astrocytic death by apoptosis, increased vacuole numbers, impaired OXPHOS activities and neuronal damage. Under HLD, Gcdhki/ki rats showed imbalance of intra- and extracellular creatine concentrations and indirect signs of an intracerebral ammonium accumulation.We successfully created the first rat model for GA-I. Characterization of this Gcdhki/ki strain confirmed that it is a suitable model not only for the study of pathophysiological processes, but also for the development of new therapeutic interventions. We further brought up interesting new insights into the pathophysiology of GA-I in brain and periphery.

Neurological manifestations in glutaric acidemia type 1 and the impact of expanded neonatal screening in Brazil

Glutaric acidemia type 1 (GA1) is an inborn error of metabolism caused by the deficiency of the enzyme glutaryl-CoA dehydrogenase, with consequent accumulation of the aminoacids lysine, hydroxylsine and tryptophan. About 1 in every 100,000 individuals are affected by the disease. Neurological manifestations are variable and include acute and chronic encephalopathic crises, dystonia, motor and cognitive deficits, as well as neuroimaging findings such as brain hypoplasia, striatal, white matter and subdural effusions. Early diagnosis is crucial for specific therapy, which includes a diet with restricted amino acids and carnitine replacement. The present work describes the variability of neurological manifestations in four patients with glutaric acidemia type 1, diagnosed in different age groups, through mass spectrometry, technology of the expanded neonatal screening available in the Ministry of Health program in Federal District, Brazil. Complications of GA1 were more severe in cases with later diagnosis, which justifies the use of the enlarged neonatal screening as an important resource in the early diagnosis and treatment of inborn errors of metabolism.

The low excretor phenotype of glutaric acidemia type I is a source of false negative newborn screening results and challenging diagnoses.

BackgroundGlutaric acidemia type I (GA1) is an organic acidemia that is often unrecognized in the newborn period until patients suffer an acute encephalopathic crisis, which can be mistaken for nonaccidental trauma. Presymptomatic identification of GA1 patients is possible by newborn screening (NBS). However, the biochemical “low‐excretor” (LE) phenotype with nearly normal levels of disease metabolites can be overlooked, which may result in untreated disease and irreversible neurological sequelae. The LE phenotype is also a potential source of false negative (FN) NBS results that merits further investigation.MethodsSamples from six LE GA1 patients were analyzed by biochemical and molecular methods and newborn screen outcomes were retrospectively investigated.ResultsFive LE GA1 patients were identified that had normal NBS results and three of these presented clinically with GA1 symptoms. One additional symptomatic patient was identified who did not undergo screening. Semiquantitative urine organic acid analysis was consistent with a GA1 diagnosis in two (33%) of the six patients, while plasma glutarylcarnitine was elevated in four (67%) of the six and urine glutarylcarnitine was elevated in four (80%) of five patients. Five GCDH variants were identified in these patients; three of which have not been previously linked to the biochemical LE phenotype.ConclusionsThe data presented here raise awareness of potential FN NBS results for LE GA1 patients. The LE phenotype is not protective against adverse clinical outcomes, and the possibility of FN NBS results calls for high vigilance amongst clinicians, even in the setting of a normal NBS result.

Clinico-Radiological Correlation in 26 Egyptian Children with Glutaric Acidemia Type 1.

Glutaric acidemia type 1 (GA1) is an inherited neurometabolic disease with significant morbidity. However, neuro-radiological correlation is not completely understood. The study aimed to characterize the neuroimaging findings and their association with neurological phenotype in GA1 children. Twenty-six Egyptian children (median age = 12 months) diagnosed with GA1 underwent clinical evaluation and brain magnetic resonance imaging (MRI). We objectively assessed the severity of neurological phenotype at the time of MRI using movement disorder (MD) and morbidity scores. Evaluation of brain MRI abnormalities followed a systematic and region-specific scoring approach. Brain MRI findings and scores were correlated with MD and morbidity scores, disease onset, and presence of seizures. Fifteen (57.7%) cases had insidious onset, eight (30.8%) manifested acute onset, whereas three (11.5%) were asymptomatic. Ten (38.5%) cases had seizures, five of which had no acute encephalopathic crisis. Putamen and caudate abnormalities (found in all acute onset, 93.3 and 73.3% of insidious onset, and one of three asymptomatic cases) were significantly related to MD (p = 0.007 and 0.013) and morbidity (p = 0.005 and 0.003) scores. Globus pallidus abnormalities (50% of acute onset, 46.7% of insidious onset, and one of three of asymptomatic cases) were significantly associated with morbidity score (p = 0.023). Other MRI brain abnormalities as well as gray and white matter score showed no significant association with neurological phenotype. Younger age at onset, acute onset, and seizures were significantly associated with worse neurological manifestations. Patients with GA1 manifest characteristic and region-specific brain MRI abnormalities, but only striatal affection appears to correlate with neurological phenotype.

The outcome of 41 Late-Diagnosed Turkish GA-1 Patients: A Candidate for the Turkish NBS

Glutaric aciduria type 1(GA-1) is an inherited cerebral organic aciduria. Untreated patients with GA-1 have a risk of acute encephalopathic crises during the first 6 years of life. In so far as GA-1 desperately does not exist in Turkish newborn screening (NBS) program, most patients in our study were late-diagnosed. This study included 41 patients diagnosed with acylcarnitine profile, urinary organic acids, mutation analyses in the symptomatic period. We presented with clinical, neuroradiological, and molecular data of our 41 patients. The mean age at diagnosis was 14.8 ± 13.9 (15 days to 72 months) and, high blood glutaconic acid, glutarylcarnitine and urinary glutaric acid (GA) levels in 41 patients were revealed. Seventeen different mutations in the glutaryl-CoA dehydrogenase gene were identified, five of which were novel. The patients, most of whom were late-diagnosed, had a poor neurological outcome. Treatment strategies made a little improvement in dystonia and the frequency of encephalopathic attacks. All GA-1 patients in our study were severely affected since they were late-diagnosed, while others show that GA-1 is a treatable metabolic disorder if it is diagnosed with NBS. This study provides an essential perspective of the severe impact on GA-1 patients unless it is diagnosed with NBS. We immediately advocate GA-1 to be included in the Turkish NBS.

Clinical and Nutritional Evolution of 24 Patients with Glutaric Aciduria Type 1 in Follow-up at a Center Specialized in Inborn Errors of Metabolism in Chile

Introduction: Glutaric Aciduria Type 1 (GA-1) is produced by the enzymatic deficiency of glutaryl-CoA-dehydrogenase (GCDH), leading to the accumulation of glutaric acid (GA). 90% of patients without early treatment present acute encephalopathic crisis (AEC), followed by disabling neurological symptoms. The treatment consists of a low lysine (Lys) diet, protein substitute lys-free, tryptophan-reduced (PS) and L-carnitine. Objectives: Describe the clinical and nutritional evolution of a cohort of GA-1 patients at a national referral center in Chile. Methodology: Retrospective study of 24 patients diagnosed with GA-1 between 1998-2020 and referred to the Institute of Nutrition and Food Technology (INTA) of University of Chile. Results: Age at diagnosis was 19±27 months; 10/24 presented AEC and neurological sequelae. The cases without AEC (14/24) 8 presented neurological compromise: psychomotor development delay, abnormal movements and pyramidal syndrome. Nutritional evaluation: 12/24 were malnourished by deficiency, <6 years old group (12/24): 11 cases were found to have Lys and PS, ≥6 years old (12/24): 9/12 did not receive PS. All had normal free carnitine levels. Conclusion: GA-1 has variable symptoms with neurological involvement AEC or insidious start. Is essential to maintain a long-term follow-up and consider its inclusion in neonatal screening programs.

A rare case of type i glutaric aciduria in an early child

Glutaric aciduria type I (deficiency of glutaryl-COA dehydrogenase, glutaric acidemia type I) is a rare autosomal recessive disease caused by mutations in the gene encoding the enzyme glutaryl – COA - dehydrogenase (GCDH). Cerebral organic aciduria, caused by a deficiency of glutaryl-COA - dehydrogenase, is generally considered a neurological disorder.The phenotypic spectrum of untreated GA-1 varies from a more common and pronounced form (a disease with infancy) to a low-symptom and less common form. In people with the same genotype, the clinical manifestations and depth of CNS damage can vary widely depending on the age of manifestation of acute encephalopathic crises. It is assumed that with early detection and treatment of “asymptomatic” newborns (in the context of screening for this disease), most people who would have developed manifestations of GA-1 with childhood or late onset will remain asymptomatic.

Audiological and otologic manifestations of glutaric aciduria type I

BackgroundGlutaric aciduria type 1 (GA-1) is a rare disease connected with speech delay and neurological deficits. However, the audiological and otologic profiles of GA-1 have not yet been fully characterized. To our knowledge, this is the largest study of comprehensive audiological and otologic evaluation in patients with GA-1 to date.MethodsThirteen patients diagnosed with GA-1 between January 1994 and December 2019 with audiological, radiological and genetic manifestations were retrospectively analyzed. Hearing tests were performed in all patients. MRI was performed for radiological evaluation.ResultsHearing loss was found in 76.9% (10/13) of GA-1 patients, including slight hearing loss in 46.1% (6/13) of patients, mild hearing loss in 15.4% (2/13) of patients, and moderate hearing loss in 7.7% (1/13) of patients. Normal hearing thresholds were seen in 23% (3/13) of patients. Patients with intensive care unit (ICU) admission history showed significantly worse hearing than those without (29.17 ± 12.47 vs 13.56 ± 3.93 dB HL, 95% CI 2.92–24.70, p = 0.0176). One patient had moderate sensorineural hearing loss and a past history of acute encephalopathic crisis. No usual causative gene mutations associated with hearing loss were found in these patients. MRI showed a normal vestibulocochlear apparatus and cochlear nerve. One patient with extensive injury of the basal ganglia on MRI after acute encephalopathic crisis was found to have moderate sensorineural hearing loss. Two patients with disability scores above 5 were found to have mild to moderate hearing impairment. No obvious correlation between macrocephaly and hearing loss was found.ConclusionA high prevalence of hearing impairment is found in GA-1 patients. Adequate audiological evaluation is essential for these patients, especially for those after encephalopathic crises or with ICU admission history.

Patterns, evolution, and severity of striatal injury in insidious- vs acute-onset glutaric aciduria type 1.

Striatal injury in patients with glutaric aciduria type 1 (GA1) results in a complex, predominantly dystonic, movement disorder. Onset may be acute following acute encephalopathic crisis (AEC) or insidious without apparent acute event. We analyzed clinical and striatal magnetic resonance imaging (MRI) findings in 21 symptomatic GA1 patients to investigate if insidious- and acute-onset patients differed in timing, pattern of striatal injury, and outcome. Eleven patients had acute and ten had insidious onset, two with later AEC (acute-on-insidious). The median onset of dystonia was 10 months in both groups, and severity was greater in patients after AEC (n = 8 severe, n = 5 moderate) than in insidious onset (n = 4 mild, n = 3 moderate, n = 1 severe). Deviations from guideline-recommended basic metabolic treatment were identified in six insidious-onset patients. Striatal lesions were extensive in all acute-onset patients and restricted to the dorsolateral putamen in eight of ten insidious-onset patients. After AEC, the two acute-on-insidious patients had extensive striatal changes superimposed on pre-existing dorsolateral putaminal lesions. Two insidious-onset patients with progressive dystonia without overt AEC also had extensive striatal changes, one with sequential striatal injury revealed by diffusion-weighted imaging. Insidious-onset patients had a latency phase of 3.5 months to 6.5 years between detection and clinical manifestation of dorsolateral putaminal lesions. Insidious-onset type GA1 is characterized by dorsolateral putaminal lesions, less severe dystonia, and an asymptomatic latency phase, despite already existing lesions. Initially normal MRI during the first months and deviations from guideline-recommended treatment in a large proportion of insidious-onset patients substantiate the protective effect of neonatally initiated treatment.

Patterns, evolution, and severity of striatal injury in insidious- versus acute-onset glutaric aciduria type 1.

Striatal injury in patients with glutaric aciduria type 1 (GA1) results in a complex, predominantly dystonic, movement disorder. Onset may be acute following acute encephalopathic crisis (AEC) or insidious without apparent acute event. We analyzed clinical and striatal magnetic resonance imaging (MRI) findings in 21 symptomatic GA1 patients to investigate if insidious- and acute-onset patients differed in timing, pattern of striatal injury, and outcome. Eleven patients had acute and ten had insidious onset, two with later AEC (acute-on-insidious). The median onset of dystonia was 10months in both groups, and severity was greater in patients after AEC (n= 8 severe, n= 5 moderate) than in insidious onset (n= 4 mild, n= 3 moderate, n= 1 severe). Deviations from guideline-recommended basic metabolic treatment were identified in six insidious-onset patients. Striatal lesions were extensive in all acute-onset patients and restricted to the dorsolateral putamen in eight of ten insidious-onset patients. After AEC, the two acute-on-insidious patients had extensive striatal changes superimposed on pre-existing dorsolateral putaminal lesions. Two insidious-onset patients with progressive dystonia without overt AEC also had extensive striatal changes, one with sequential striatal injury revealed by diffusion-weighted imaging. Insidious-onset patients had a latency phase of 3.5months to 6.5years between detection and clinical manifestation of dorsolateral putaminal lesions. Insidious-onset type GA1 is characterized by dorsolateral putaminal lesions, less severe dystonia, and an asymptomatic latency phase, despite already existing lesions. Initially normal MRI during the first months and deviations from guideline-recommended treatment in a large proportion of insidious-onset patients substantiate the protective effect of neonatally initiated treatment.

Glutaric AciduriaType 1: Clinical and Molecular Study in Iranian Patients, 3 Novel Mutations.

Glutaricaciduria type 1 (GA1), is a rare, treatable neuro metabolic disease, due to glutaryl- CoA dehydrogenase (GCDH) gene mutation.In regions without neonatal blood screening (NBS), patients are diagnosed in symptomatic period. This study was carried out to assess patients with GA1 for clinical, biochemical, neuroimaging findings and GCDH gene mutations analysis. In this cross-sectional study, clinical manifestation, neuroimaging and metabolic findings of eleven Iranian GA1 patients of MofidChildren's Hospital, Tehran, Iranbetween 2001 and 2011,were evaluated.Mutational analysis of the GCDH gene was performed on genomic DNA. Genomic DNA was extracted from peripheral lymphocytes using QIAamp DNA Micro Kit (Qiagen). All 11 exons and flanking intronic regions of the GCDH gene were amplified by polymerase chain reaction (PCR). All patients were diagnosed before 32 months old. Clinical presentations of GA1 include acute encephalopathic crisis and/or developmental delay and macrocephaly. Seven GCDH gene mutations were detected in our patients. The most frequent GCDH mutations occurred in exon7 then exon8, 10 and11. G244 C in exon7, R294 Q in exon8 and N373 S in exon 10 were three novel mutations. There was no correlation between of genotype and phenotype in our patients. Physician must remember GA1 in differential diagnosis of acute encephalopathic crisis, macrocephaly, developmental delay, movement disorders such as dystonia and dyskinesia. Early detection, proper treatment and selective screening of patients' siblings can prevent neurologic disabilities.

Proposed recommendations for diagnosing and managing individuals with glutaric aciduria type I: second revision.

Glutaric aciduria type I (GA-I; synonym, glutaric acidemia type I) is a rare inherited metabolic disease caused by deficiency of glutaryl-CoA dehydrogenase located in the catabolic pathways of L-lysine, L-hydroxylysine, and L-tryptophan. The enzymatic defect results in elevated concentrations of glutaric acid, 3-hydroxyglutaric acid, glutaconic acid, and glutaryl carnitine in body tissues, which can be reliably detected by gas chromatography/mass spectrometry (organic acids) and tandem mass spectrometry (acylcarnitines). Most untreated individuals with GA-I experience acute encephalopathic crises during the first 6 years of life that are triggered by infectious diseases, febrile reaction to vaccinations, and surgery. These crises result in striatal injury and consequent dystonic movement disorder; thus, significant mortality and morbidity results. In some patients, neurologic disease may also develop without clinically apparent crises at any age. Neonatal screening for GA-I us being used in a growing number of countries worldwide and is cost effective. Metabolic treatment, consisting of low lysine diet, carnitine supplementation, and intensified emergency treatment during catabolism, is effective treatment and improves neurologic outcome in those individuals diagnosed early; treatment after symptom onset, however, is less effective. Dietary treatment is relaxed after age 6years and should be supervised by specialized metabolic centers. The major aim of this second revision of proposed recommendations is to re-evaluate the previous recommendations (Kölker et al. J Inherit Metab Dis 30:5-22, 2007b; J Inherit Metab Dis 34:677-694, 2011) and add new research findings, relevant clinical aspects, and the perspective of affected individuals.

Immunolocalization of glutaryl-CoA dehydrogenase (GCDH) in adult and embryonic rat brain and peripheral tissues

Glutaryl-CoA dehydrogenase (GCDH) is a mitochondrial enzyme that is involved in the degradation of tryptophan, lysine and hydroxylysine. Deficient enzyme activity leads to glutaric aciduria type-I (GA-I). This neurometabolic disease usually manifests with acute encephalopathic crises and striatal neuronal death in early childhood leading to an irreversible dystonic-dyskinetic movement disorder. Fronto-temporal atrophy and white matter changes are already present in the pre-symptomatic period. No detailed information on GCDH expression during embryonic development and in adulthood was available so far.Using immunofluorescence microscopy and cell-type-specific markers to localize GCDH in different tissues, we describe the differential cellular localization of GCDH in adult rat brain and peripheral organs as well as its spatiotemporal expression pattern.During embryonic development GCDH was predominantly expressed in neurons of the central and peripheral nervous system. Significant expression levels were found in epithelial cells (skin, intestinal and nasal mucosa) of rat embryos at different developmental stages. Besides the expected strong expression in liver, GCDH was found to be significantly expressed in neurons of different brain regions, renal proximal tubules, intestinal mucosa and peripheral nerves of adult rats.GCDH was found widely expressed in embryonic and adult rat tissues. In rat embryos GCDH is predominantly expressed in brain implying an important role for brain development. Interestingly, GCDH was found to be significantly expressed in different other organs (e.g. kidney, gut) in adult rats probably explaining the evolving phenotype in GA-I patients.