Glutaric acidemia type I: a neurosurgical perspective. Report of two cases

Evaluation of the Clinical, Biochemical, Neurological, and Genetic Presentations of Glutaric Aciduria Type 1 in Patients From China

Purpose

To characterize the phenotypic and genotypic variations associated with Glutaric aciduria type 1 (GA1) in Chinese patients.

Methods

We analyzed the clinical, neuroradiological, biochemical, and genetic information from 101 GA1 patients in mainland China.

Results

20 patients were diagnosed by newborn screening and the remaining 81 cases were identified following clinical intervention. Macrocephaly was the most common presentation, followed by movement disorders and seizures. A total of 59 patients were evaluated by brain MRI and 58 patients presented with abnormalities, with widening of the sylvian fissures being the most common symptom. The concentration of glutarylcarnitine in the blood, glutarylcarnitine/capryloylcarnitine ratio, and urine levels of glutaric acid were increased in GA1 patients and were shown to decrease following intervention. A total of 88 patient samples were available for genotyping and 74 variants within the GCDH gene, including 23 novel variants, were identified. The most common variant was c.1244-2A > C (18.4%) and there were no significant differences in the biochemical or clinical phenotypes described for patients with the four most common variants: c.1244-2A > C, c.1064G > A, c.533G > A, and c.1147C > T. Patients identified by newborn screening had better outcomes than clinical patients.

Conclusion

Our findings expand the spectrum of phenotypes and genotypes for GA1 in Chinese populations and suggest that an expanded newborn screening program using tandem mass spectrometry may facilitate the early diagnosis and treatment of this disease, improving clinical outcomes for patients in China.

Occurrence of subdural hematomas in Dutch glutaric aciduria type 1 patients

Patients with glutaric aciduria type 1 (GA1), a rare inherited metabolic disorder, have an increased risk for subdural hematomas (SDHs). GA1 is therefore generally included in the differential diagnosis of children presenting with SDHs. This retrospective cohort study reviews all 25 registered, in the Dutch Diagnosis Registration for Metabolic Disorders, GA1 patients in the Netherlands. This was done between May 2014 and November 2014 to determine the lifetime incidence of SDHs in this population. Seventeen patients were diagnosed either due to clinical symptoms or because of family members with GA1. One out of these 17 had a SDH. This patient showed widened Sylvian fissures on MRI, characteristic for GA1. Eight patients were diagnosed by newborn screening. Three of them had neuroimaging results, and none of them had SDHs. This study shows an overall lower incidence (4.0 %) of SDHs in patients with GA1 than reported in the literature (20-30 %).

CONCLUSION

This finding, in combination with the fact that SDHs in GA1 appear to occur only in the presence of characteristic brain abnormalities on imaging, we recommend that GA1 should not routinely be a part of the differential diagnosis of children with unexplained SDHs in the absence of imaging characteristics suggestive of GA1.

WHAT IS KNOWN

• Glutaric aciduria type 1 is a rare metabolic disorder predisposing children to subdural hematoma development due to brain abnormalities. • Because of these subdural hematomas, glutaric aciduria type 1 testing is part of abusive head trauma work-up. What is new: • The overall subdural hematoma incidence in glutaric aciduria type 1 patients is much lower than previously reported and only occurs in case of predisposing brain abnormalities.

In Vivo NMR Studies of the Brain with Hereditary or Acquired Metabolic Disorders

Metabolic disorders, whether hereditary or acquired, affect the brain, and abnormalities of the brain are related to cellular integrity; particularly in regard to neurons and astrocytes as well as interactions between them. Metabolic disturbances lead to alterations in cellular function as well as microscopic and macroscopic structural changes in the brain with diabetes, the most typical example of metabolic disorders, and a number of hereditary metabolic disorders. Alternatively, cellular dysfunction and degeneration of the brain lead to metabolic disturbances in hereditary neurological disorders with neurodegeneration. Nuclear magnetic resonance (NMR) techniques allow us to assess a range of pathophysiological changes of the brain in vivo. For example, magnetic resonance spectroscopy detects alterations in brain metabolism and energetics. Physiological magnetic resonance imaging (MRI) detects accompanying changes in cerebral blood flow related to neurovascular coupling. Diffusion and T1/T2-weighted MRI detect microscopic and macroscopic changes of the brain structure. This review summarizes current NMR findings of functional, physiological and biochemical alterations within a number of hereditary and acquired metabolic disorders in both animal models and humans. The global view of the impact of these metabolic disorders on the brain may be useful in identifying the unique and/or general patterns of abnormalities in the living brain related to the pathophysiology of the diseases, and identifying future fields of inquiry.

Subdural hematomas: glutaric aciduria type 1 or abusive head trauma? A systematic review

Purpose

Glutaric aciduria type 1 (GA1) is a rare metabolic disorder of glutaryl-CoA-dehydrogenase enzyme deficiency. Children with GA1 are reported to be predisposed to subdural hematoma (SDH) development due to stretching of cortical veins secondary to cerebral atrophy and expansion of CSF spaces. Therefore, GA1 testing is part of the routine work-up in abusive head trauma (AHT). This systematic review addresses the coexistence of GA1 and SDH and the validity of GA1 in the differential diagnosis of AHT.

Methods

A systematic literature review, with language restriction, of papers published before 1 Jan 2015, was performed using Pubmed, PsychINFO, and Embase. Inclusion criteria were reported SDHs, hygromas or effusions in GA1 patients up to 18 years of age. Of 1599 publications, 20 publications were included for analysis.

Results

In total 20 cases, 14 boys and 6 girls, were included. In eight cases (40 %) a child abuse work-up was performed, which was negative in all cases. Clinical history revealed the presence of trauma in eight cases (40 %). In only one case neuroradiology revealed no abnormalities related to GA1 according to the authors, although on evaluation we could not exclude AHT.

Conclusion

From this systematic review we conclude that SDHs in 19/20 children with GA1 are accompanied by other brain abnormalities specific for GA1. One case with doubtful circumstances was the exception to this rule.