Case reports: novel TUBG1 mutations with milder neurodevelopmental presentations.

BACKGROUND: Tubulinopathies result from mutations in tubulin genes, including TUBG1, responsible for cell microtubules, are characterized by brain development abnormalities, microcephaly, early-onset epilepsy, and motor impairment. Only eleven patients with TUBG1 mutations have been previously described in literature to our knowledge. Here we present two new patients with novel de novo TUBG1 mutations and review other cases in the literature. CASE PRESENTATIONS: Both patients have microcephaly and intellectual disability. Patient B further fits a more typical presentation, with well-controlled epilepsy and mild hypertonia, whereas Patient A's presentation is much milder without these other features. CONCLUSION: This report expands the spectrum of TUBG1 mutation manifestations, suggesting the possibility of less severe phenotypes for patients and families, and influencing genetic counselling strategies.

Low plasma magnesium is associated with impaired brain metabolism in neonates with hypoxic-ischaemic encephalopathy.

AIM: To determine the association between lowest plasma magnesium concentration and brain metabolism, and whether magnetic resonance imaging brain injury patterns moderated the association in hypoxic-ischemic encephalopathy. METHODS: In 131 early (day-of-life 3) and 65 late (day-of-life 10) scans of term encephalopathic infants born between 2004 and 2012, we examined the association of lowest plasma magnesium (until day-of-life 3) on basal ganglia and white matter peak metabolite ratios on magnetic resonance spectroscopy independent of covariates, stratified by the predominant patterns of injury (normal, basal nuclei/total, watershed, multifocal) using multiple linear regression. RESULTS: Lowest plasma magnesium was associated with lower white matter N-acetyl-aspartate/choline in the multifocal pattern on early scan (regression-coefficient, ß: 0.13; 95% CI: 0.04, 0.22) and in the basal nuclei/total pattern on late scan (ß: 0.08; 95% CI: 0.02, 0.15), and was negatively associated with basal ganglia lactate/N-acetyl-aspartate (ß: -0.16; 95% CI: -0.05, -0.28) and lactate/choline (ß: -0.1; 95% CI: -0.03, -0.17) ratio in the basal nuclei/total pattern on late scan independent of hypomagnesaemia correction, cooling and postmenstrual age at scan. Lowest plasma magnesium was not associated with metabolite ratios in other brain injury patterns. CONCLUSION: In infants with hypoxic-ischaemic encephalopathy, predominant patterns of brain injury moderated the association between lowest plasma magnesium in the first three days of life and impaired brain metabolism.

Expansion of the QARS deficiency phenotype with report of a family with isolated supratentorial brain abnormalities.

We describe a family with QARS deficiency due to compound heterozygous QARS mutations, including c.1387G > A (p.R463*) in the catalytic core domain and c.2226C > G (p.Q742H) in the anticodon domain, both previously unreported and predicted damaging. The phenotype of the male index further confirms this specific aminoacyl-transfer RNA (tRNA) synthetase disorder as a novel genetic cause of progressive microcephaly with diffuse cerebral atrophy, severely deficient myelination, intractable seizures, and developmental arrest. However, in contrast to the two hitherto published families, the cerebellum and its myelination are not affected. An awareness that QARS mutations may cause isolated supratentorial changes is crucial for properly directing genetic analysis.

Evolution of pattern of injury and quantitative MRI on days 1 and 3 in term newborns with hypoxic-ischemic encephalopathy.

BACKGROUND: Brain injury in term neonatal hypoxic-ischemic encephalopathy (HIE) emerges on magnetic resonance imaging (MRI) by day 3. This study aimed to address the relationship of MRI, diffusion tensor imaging (DTI), and MR spectroscopic imaging (MRSI) findings on days 1 and 3 in a prospective cohort of term newborns with HIE. METHODS: A total of 24 term newborns with HIE were prospectively studied with MRI on days 1 and 3; 19 were imaged with DTI and MRSI on days 1 and 3. MRI was assessed using validated scores. The relationship between MRI, DTI, and MRSI values on days 1 and 3 was determined using linear regression for repeated measures. RESULTS: Conventional MRI showed a complex variation of findings from day 1 to 3. In gray matter, mean diffusivity (Dav) and metabolite ratios measured on day 1 were predictive of values on day 3 (all P ≤ 0.04). In white matter, Dav, fractional anisotropy (FA), and N-acetylaspartate (NAA)/choline on days 1 and 3 were strongly related (all P ≤ 0.003). Hypothermia appeared to attenuate the severity and progression of brain injury in the six treated newborns. CONCLUSION: In term newborns with HIE, quantitative MR values on days 1 and 3 are strongly associated, providing an objective measure of injury before qualitative images.

White matter injury in term newborns with neonatal encephalopathy.

White matter injury (WMI) is the characteristic pattern of brain injury detected on magnetic resonance imaging in the premature newborn. Focal noncystic WMI is increasingly recognized in populations of term newborns. The aim of this study was to describe the occurrence of focal noncystic WMI in a cohort of 48 term newborns with encephalopathy studied with magnetic resonance imaging at 72 +/- 12 h of life, and to identify clinical risk factors for this pattern of injury. Eleven newborns (23%; 95% CI 11-35) were found to have WMI (four minimal, three moderate, and four severe). In 10 of the 11 newborns, the WMI was associated with restricted diffusion on apparent diffusion coefficient maps. An increasing severity of WMI was associated with lower gestational age at birth (p = 0.05), but not lower birth weight. Newborns with WMI had milder encephalopathy and fewer clinical seizures relative to other newborns in the cohort. Other brain injuries were seen in three of the 11 newborns: basal nuclei predominant pattern of injury in one and cortical strokes in two. These findings suggest that WMI in the term newborn is acquired near birth and that the state of brain maturation is an important determinant of this pattern of brain injury.

Pattern of Brain Injury Predicts Long-Term Epilepsy Following Neonatal Encephalopathy.

OBJECTIVE: To determine if patterns of hypoxic-ischemic brain injury on magnetic resonance imaging (MRI) in term newborns predict subsequent childhood epilepsy. METHODS: This retrospective cohort study includes term newborns with encephalopathy (n = 181) born between 2004-2012 and admitted to British Columbia Children's Hospital. MRI was performed between 3 and 5 days of age. The predominant patterns of hypoxic-ischemic injury were classified as Normal, Watershed, Basal Nuclei, Total, and Focal-Multifocal. Lesions in hippocampus, motor and occipital cortex were noted. RESULTS: Of 181 newborns, 166 (92%) survived the neonatal period, and 132 (80%) had follow-up with a median duration of 61 months (IQR: 28-95). Twenty-three children (17%) developed epilepsy. A higher proportion with Watershed, Basal Nuclei, or Total patterns developed epilepsy (P < .001). Injury to motor cortex, hippocampus, and occipital lobe (P < .01) were independent risk factors for epilepsy. In the adjusting logistic model, Watershed (odds ratio = 16.0, 95% CI [1.3, 197.2], P = .03) and Basal Nuclei injury (odds ratio = 19.4, 95% CI [1.9, 196.3], P = .01) remained independent risk factors. Therapeutic hypothermia did not alter these associations. Severity of brain injury and recurrent neonatal seizures are other clinical risk factors. SIGNIFICANCE: In term newborns with hypoxic-ischemic encephalopathy, the predominant pattern of Watershed and Basal Nuclei injury are valuable predictors for development of epilepsy in later childhood.

Case Report.

Glutaminyl-tRNA synthetase (QARS) deficiency has been described to be a cause of a neurodegenerative disorder associated with severe developmental delay, microcephaly, delayed myelination, and intractable epilepsy. The epilepsy is thought to be more severe than other tRNA synthetase disorders. Only a few cases have been reported in the literature and there is little information about response to different treatment options. The ketogenic diet is a high-fat, low-carbohydrate diet that is used in treatment resistant epilepsy of various etiologies. There are reports that the diet can also improve neuro-cognitive parameters. The authors report a case of a patient with glutaminyl-tRNA synthetase deficiency and treatment resistant seizures where there was a marked and early favorable response in terms of seizures, alertness and behavior to the ketogenic diet.

Reliability of Early Magnetic Resonance Imaging (MRI) and Necessity of Repeating MRI in Noncooled and Cooled Infants With Neonatal Encephalopathy.

In cooled newborns with encephalopathy, although late magnetic resonance imaging (MRI) scan (10-14 days of age) is reliable in predicting long-term outcome, it is unknown whether early scan (3-6 days of life) is. We compared the predominant pattern and extent of lesion between early and late MRI in 89 term neonates with neonatal encephalopathy. Forty-three neonates (48%) were cooled. The predominant pattern of lesions and the extent of lesion in the watershed region agreed near perfectly in noncooled (kappa = 0.94; k = 0.88) and cooled (k = 0.89; k = 0.87) infants respectively. There was perfect agreement in the extent of lesion in the basal nuclei in noncooled infants (k = 0.83) and excellent agreement in cooled infants (k = 0.67). Changes in extent of lesions on late MRI occurred in 19 of 89 infants, with higher risk in infants with hypoglycemia and moderate-severe lesions in basal nuclei. In most term neonates with neonatal encephalopathy, early MRI (relative to late scan) robustly predicts the predominant pattern and extent of injury.

Cerebellar vermian atrophy after neonatal hypoxic-ischemic encephalopathy.

BACKGROUND AND PURPOSE: Although pathologic evidence of cerebellar injury due to birth asphyxia is well described, neuroimaging evidence is sparse. The primary purpose of this retrospective study was to evaluate the early and late imaging findings in the cerebellum of patients who had neonatal hypoxic-ischemic encephalopathy with thalamic edema shown by neonatal CT. The secondary aims were to validate thalamic edema shown by neonatal CT as a marker of thalamic injury and to assess the late cerebral cortical abnormalities associated with neonatal thalamic edema. METHODS: Fifty-five neonates with thalamic edema shown by CT performed when patients were 3 days old were identified from a cohort of full-term neonates with hypoxic-ischemic encephalopathy. Twenty-six of the 55 underwent follow-up neuroimaging. All sonograms, CT scans, and MR images of the brains of the 55 neonates were retrospectively reviewed by two pediatric neuroradiologists. The examinations were reviewed for evidence of hemorrhage, edema, atrophy, and CT attenuation or MR signal intensity abnormalities in the cerebellum, basal ganglia, and cerebral cortex. The neonatal autopsy findings in four cases were reviewed separately by a pediatric neuropathologist. RESULTS: Of the 55 neonates with thalamic edema shown by neonatal CT, 28 (51%) had thalamic edema with diffuse cerebral cortical edema, and 27 (49%) had thalamic edema without diffuse cortical edema. The cerebellar vermes appeared normal on all neonatal sonograms, CT scans, and MR images. However, atrophy of the cerebellar vermis was found in 12 (46%) of 26 patients by use of follow-up studies (95% CI, 27-65%). One of the 12 patients also had cerebellar hemispheric atrophy. Cerebellar vermian atrophy was shown at follow-up in eight (67%) of 12 patients who had neonatal thalamic edema with cortical sparing, compared with four (29%) of 14 patients who had thalamic edema with diffuse cortical edema. The difference did not reach statistical significance. The thalami appeared abnormal on follow-up neuroimages in 25 of 26 cases. Different patterns of cortical atrophy were observed on the images of patients who had thalamic edema with cortical sparing compared with those obtained in patients who had thalamic edema with cortical involvement. CONCLUSION: Cerebellar vermian atrophy is a frequent finding on follow-up images of patients in whom neonatal CT showed hypoxic-ischemic encephalopathy with abnormal thalami.

Germinal matrix-intraventricular hemorrhage in the premature newborn: management and outcome.

Germinal matrix-intraventricular hemorrhage (GMH-IVH) in the premature newborn results from rupture of fragile capillaries in the germinal matrix. Its pathogenesis is multifactorial and relates principally to a pressure-passive cerebral circulation, fluctuations in cerebral blood flow, and derangements of coagulation and fragility of the germinal matrix microvasculature. Several interventions have beneficial effects for prevention of GMH-IVH. Outcome after GMH-IVH relates largely to the severity of hemorrhage, the extent of hemorrhagic and ischemic parenchymal involvement, and complications (e.g., posthemorrhagic hydrocephalus). Even in the absence of neuroimaging abnormalities, VLBW infants have a high incidence of academic and behavioral problems which persist into adolescence and early adulthood.

The role of hypoxia-ischemia in term newborns with arterial stroke.

The role of generalized hypoxia-ischemia in the genesis of perinatal focal arterial stroke remains puzzling. Animal studies have demonstrated that hypoxia-ischemia may alter blood flow through the ductus venosus, thereby increasing the risk for placental emboli entering the cerebral circulation. A retrospective review was performed of clinical records of all term newborns admitted to a tertiary perinatal center between January 1995 and May 2007 with acute arterial stroke on neuroimaging during the first week of life. Newborns were classified into 2 groups on the basis of neuroimaging abnormalities: stroke alone, or stroke and nonfocal hypoxic-ischemic brain injury. A total of 62 newborns had focal or multifocal stroke, 36 with stroke alone and 26 with stroke with nonfocal hypoxia-ischemia. Multiple risk factors for hypoxia-ischemia occurred in most newborns in both groups. These data indicate that hypoxia-ischemia may play a role in the genesis of stroke in the term newborn with or without evidence of nonfocal hypoxic-ischemic brain injury on neuroimaging.

Comparison of computer tomography and magnetic resonance imaging scans on the third day of life in term newborns with neonatal encephalopathy.

OBJECTIVE: Our goal was to compare the patterns of brain injury detected by computed tomography, conventional MRI (T1- and T2-weighted sequences), and diffusion-weighted MRI in a cohort of term newborns with neonatal encephalopathy studied uniformly with all 3 modalities on the third day of life. METHODS: Term newborns (> or =36 weeks' gestation) admitted to our center with neonatal encephalopathy were scanned with computed tomography, MRI, and diffusion-weighted MRI at 72 (+/-12) hours of life (n = 48). Each modality was scored independently of the other with previously validated scoring systems. The predominant pattern of brain injury was classified as: normal, watershed, basal nuclei, total (maximal basal nuclei and watershed), and focal-multifocal (presence of strokes and/or white matter injury alone). RESULTS: The agreement for the predominant pattern of injury was excellent between MRI and diffusion-weighted MRI (77% agreement). The agreement for the pattern of injury was also good for computed tomography and diffusion-weighted MRI (67% agreement). The extent of cortical injury and focal-multifocal lesions, such as strokes and white matter injury, were less apparent on computed tomography than diffusion-weighted MRI. In 19 newborns with a repeat MRI in the second week of life, the predominant pattern seen on the day 3 diffusion-weighted MRI was confirmed. CONCLUSIONS: Diffusion-weighted MRI is the most sensitive technique with which to assess brain injury on day 3 of life in term newborns with neonatal encephalopathy, particularly for cortical injury and focal-multifocal lesions such as stroke and white matter injury. All 3 modalities identify the most serious patterns of brain injury similarly.