The Saccadic and Neurological Deficits in Type 3 Gaucher Disease

Our objective was to characterize the saccadic eye movements in patients with type 3 Gaucher disease (chronic neuronopathic) in relationship to neurological and neurophysiological abnormalities. For approximately 4 years, we prospectively followed a cohort of 15 patients with Gaucher type 3, ages 8–28 years, by measuring saccadic eye movements using the scleral search coil method. We found that patients with type 3 Gaucher disease had a significantly higher regression slope of duration vs amplitude and peak duration vs amplitude compared to healthy controls for both horizontal and vertical saccades. Saccadic latency was significantly increased for horizontal saccades only. Downward saccades were more affected than upward saccades. Saccade abnormalities increased over time in some patients reflecting the slowly progressive nature of the disease. Phase plane plots showed individually characteristic patterns of abnormal saccade trajectories. Oculo-manual dexterity scores on the Purdue Pegboard test were low in virtually all patients, even in those with normal cognitive function. Vertical saccade peak duration vs amplitude slope significantly correlated with IQ and with the performance on the Purdue Pegboard but not with the brainstem and somatosensory evoked potentials. We conclude that, in patients with Gaucher disease type 3, saccadic eye movements and oculo-manual dexterity are representative neurological functions for longitudinal studies and can probably be used as endpoints for therapeutic clinical trials

A novel approach of homozygous haplotype sharing identifies candidate genes in autism spectrum disorder

Autism spectrum disorder (ASD) is a highly heritable disorder of complex and heterogeneous aetiology. It is primarily characterized by altered cognitive ability including impaired language and communication skills and fundamental deficits in social reciprocity. Despite some notable successes in neuropsychiatric genetics, overall, the high heritability of ASD (~90%) remains poorly explained by common genetic risk variants. However, recent studies suggest that rare genomic variation, in particular copy number variation, may account for a significant proportion of the genetic basis of ASD. We present a large scale analysis to identify candidate genes which may contain low-frequency recessive variation contributing to ASD while taking into account the potential contribution of population differences to the genetic heterogeneity of ASD. Our strategy, homozygous haplotype (HH) mapping, aims to detect homozygous segments of identical haplotype structure that are shared at a higher frequency amongst ASD patients compared to parental controls. The analysis was performed on 1,402 Autism Genome Project trios genotyped for 1 million single nucleotide polymorphisms (SNPs). We identified 25 known and 1,218 novel ASD candidate genes in the discovery analysis including CADM2, ABHD14A, CHRFAM7A, GRIK2, GRM3, EPHA3, FGF10, KCND2, PDZK1, IMMP2L and FOXP2. Furthermore, 10 of the previously reported ASD genes and 300 of the novel candidates identified in the discovery analysis were replicated in an independent sample of 1,182 trios. Our results demonstrate that regions of HH are significantly enriched for previously reported ASD candidate genes and the observed association is independent of gene size (odds ratio 2.10). Our findings highlight the applicability of HH mapping in complex disorders such as ASD and offer an alternative approach to the analysis of genome-wide association data

CSF and Blood Levels of GFAP in Alexander Disease(1,2,3).

Alexander disease is a rare, progressive, and generally fatal neurological disorder that results from dominant mutations affecting the coding region of GFAP, the gene encoding glial fibrillary acidic protein, the major intermediate filament protein of astrocytes in the CNS. A key step in pathogenesis appears to be the accumulation of GFAP within astrocytes to excessive levels. Studies using mouse models indicate that the severity of the phenotype correlates with the level of expression, and suppression of GFAP expression and/or accumulation is one strategy that is being pursued as a potential treatment. With the goal of identifying biomarkers that indirectly reflect the levels of GFAP in brain parenchyma, we have assayed GFAP levels in two body fluids in humans that are readily accessible as biopsy sites: CSF and blood. We find that GFAP levels are consistently elevated in the CSF of patients with Alexander disease, but only occasionally and modestly elevated in blood. These results provide the foundation for future studies that will explore whether GFAP levels can serve as a convenient means to monitor the progression of disease and the response to treatment

Early-Onset Vascular Leukoencephalopathy Caused by Bi-Allelic NOTCH3 Variants

Objective Heterozygous NOTCH3 variants are known to cause cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL), with patients typically presenting in adulthood. We describe three patients presenting at an early age with a vascular leukoencephalopathy. Genome sequencing revealed bi-allelic variants in the NOTCH3 gene. Methods Clinical records and available MRI and CT scans of three patients from two unrelated families were retrospectively reviewed. Results The patients presented at 9 to 14 months of age with developmental delay, seizures, or both. The disease course was characterized by cognitive impairment and variably recurrent strokes, migraine attacks, and seizures. MRI findings pointed at a small vessel disease, with extensive cerebral white matter abnormalities, atrophy, lacunes in the basal ganglia, microbleeds, and microcalcifications. The anterior temporal lobes were spared. Bi-allelic cysteine-sparing NOTCH3 variants in exons 1, 32, and 33 were found. Interpretation This study indicates that bi-allelic loss-of-function NOTCH3 variants may cause a vascular leukoencephalopathy, distinct from CADASIL

Appointment completion in pediatric neurology telemedicine clinics serving underserved patients.

BackgroundTo determine whether telemedicine improves access to outpatient neurology care for underserved patients, we compared appointment completion between urban, in-person clinics and telemedicine clinics held in rural and underserved communities where neurology consultations are provided remotely.MethodsIn this retrospective study, we identified patients scheduled for outpatient care from UCDH pediatric neurologists between January 1, 2009, and July 31, 2017, in person and by telemedicine. Demographic and clinical variables were abstracted from electronic medical records. We evaluated the association between consultation modality and visit completion in overall and matched samples using hierarchical multivariable logistic regression.ResultsWe analyzed 13,311 in-person appointments by 3,831 patients and 1,158 telemedicine appointments by 381 patients. The average travel time to the site of care was 45.8 ± 52.1 minutes for the in-person cohort and 22.3 ± 22.7 minutes for the telemedicine cohort. Telemedicine sites were located at an average travel time of 217.1 ± 114.8 minutes from UCDH. Telemedicine patients were more likely to have nonprivate insurance, lower education, and lower household income. They had different diagnoses and fewer complex chronic conditions. Telemedicine visits were more likely to be completed than either "cancelled" or missed ("no show") compared with in-person visits (OR 1.57, 95% CI: 1.34-1.83; OR 1.66, 95% CI: 1.31-2.10 matched on travel time to the site of care; OR 2.22, 95% CI: 1.66-2.98 matched on travel time to UCDH).ConclusionsThe use of telemedicine for outpatient pediatric neurology visits has high odds of completion and can serve as an equal adjunct to in-person clinic visits

Randomized, controlled trial of miglustat in Gaucher\u27s disease type 3

To evaluate the efficacy and safety of miglustat, concomitant with enzyme replacement therapy (ERT), in patients with Gaucher's disease type 3 (GD3). This 24-month, phase II, open-label clinical trial of miglustat in GD3 was conducted in two phases. During the initial 12 months, patients were randomized 2:1 to receive miglustat or "no miglustat treatment." The randomized phase was followed by an optional 12-month extension phase in which all patients received miglustat. All patients received ERT during the 24-month period. The primary efficacy end points were change from baseline to months 12 and 24 in vertical saccadic eye movement velocity as determined by the peak amplitude versus amplitude regression line slope. Secondary end points included changes in neurological and neuropsychological assessments, pulmonary function tests, liver and spleen organ volumes, hematological and clinical laboratory assessments, and safety evaluations. Thirty patients were enrolled, of whom 21 were randomized to miglustat and 9 to "no miglustat treatment." Twenty-eight patients entered the 12-month extension phase. No significant between-group differences in vertical saccadic eye movement velocity or in the other neurological or neuropsychological evaluations were observed. Organ volumes and hematological parameters remained stable in both treatment groups, but improvement in pulmonary function and decrease of chitotriosidase levels were observed with miglustat compared with patients receiving ERT alone. Miglustat does not appear to have significant benefits on the neurological manifestations of GD3. However, miglustat may have positive effects on systemic disease (pulmonary function and chitotriosidase activity) in addition to ERT in patients with GD

Large exonic deletions in POLR3B gene cause POLR3-related leukodystrophy

POLR3-related (or 4H) leukodystrophy is an autosomal recessive disorder caused by mutations in POLR3A or POLR3B and is characterized by neurological and non-neurological features. In a small proportion of patients, no mutation in either gene or only one mutation is found. Analysis of the POLR3B cDNA revealed a large deletion of exons 21–22 in one case and of exons 26–27 in another case. These are the first reports of long deletions causing POLR3-related leukodystrophy, suggesting that deletions and duplications in POLR3A or POLR3B should be investigated in patients with a compatible phenotype, especially if one pathogenic variant has been identified