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.

Endocrine and Growth Abnormalities in 4H Leukodystrophy Caused by Variants in POLR3A, POLR3B, and POLR1C.

CONTEXT: 4H or POLR3-related leukodystrophy is an autosomal recessive disorder typically characterized by hypomyelination, hypodontia, and hypogonadotropic hypogonadism, caused by biallelic pathogenic variants in POLR3A, POLR3B, POLR1C, and POLR3K. The endocrine and growth abnormalities associated with this disorder have not been thoroughly investigated to date. OBJECTIVE: To systematically characterize endocrine abnormalities of patients with 4H leukodystrophy. DESIGN: An international cross-sectional study was performed on 150 patients with genetically confirmed 4H leukodystrophy between 2015 and 2016. Endocrine and growth abnormalities were evaluated, and neurological and other non-neurological features were reviewed. Potential genotype/phenotype associations were also investigated. SETTING: This was a multicenter retrospective study using information collected from 3 predominant centers. PATIENTS: A total of 150 patients with 4H leukodystrophy and pathogenic variants in POLR3A, POLR3B, or POLR1C were included. MAIN OUTCOME MEASURES: Variables used to evaluate endocrine and growth abnormalities included pubertal history, hormone levels (estradiol, testosterone, stimulated LH and FSH, stimulated GH, IGF-I, prolactin, ACTH, cortisol, TSH, and T4), and height and head circumference charts. RESULTS: The most common endocrine abnormalities were delayed puberty (57/74; 77% overall, 64% in males, 89% in females) and short stature (57/93; 61%), when evaluated according to physician assessment. Abnormal thyroid function was reported in 22% (13/59) of patients. CONCLUSIONS: Our results confirm pubertal abnormalities and short stature are the most common endocrine features seen in 4H leukodystrophy. However, we noted that endocrine abnormalities are typically underinvestigated in this patient population. A prospective study is required to formulate evidence-based recommendations for management of the endocrine manifestations of this disorder.

Appointment completion in pediatric neurology telemedicine clinics serving underserved patients.

BACKGROUND: To 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. METHODS: In 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. RESULTS: We 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). CONCLUSIONS: The 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.

Hospital Utilization Among Rural Children Served by Pediatric Neurology Telemedicine Clinics.

Importance: Telemedicine is increasingly used to provide outpatient pediatric neurology consultations in underserved communities. Although telemedicine clinics have been shown to improve access, little is known about how they alter patients' utilization of hospital services. Objective: To evaluate the association between access to telemedicine clinics and hospital utilization among underserved children with neurologic conditions. Design, Setting, and Participants: This retrospective cross-sectional study included 4169 patients who received outpatient care from pediatric neurologists affiliated with an academic children's hospital in California between January 1, 2009, and July 31, 2017, either in person or using telemedicine. Exposures: Consultation modality (telemedicine or in person) in the outpatient neurology clinics. Main Outcomes and Measures: Demographic and clinical variables were abstracted from the hospital's electronic medical records. The association between the modality of outpatient neurology care and patients' utilization of the emergency department and hospitalizations was evaluated. Both all-cause and neurologic condition-related hospital utilization were analyzed using multivariable negative binomial regression in overall and matched samples. Results: The telemedicine cohort comprised 378 patients (211 [55.8%] male), and the in-person cohort comprised 3791 patients (2090 [55.1%] male). The mean (SD) age at the first encounter was 7.4 (5.4) years for the telemedicine cohort and 7.8 (5.1) years for the in-person cohort. The telemedicine cohort was more likely than the in-person cohort to have nonprivate insurance (public insurance, self-pay, or uninsured), lower education, and lower household income. The rates of all-cause and neurologic hospital encounters were lower among children who received pediatric neurology consultations over telemedicine compared with children who received care in the in-person clinics (5.7 [95% CI, 3.5-8.0] vs 20.1 [95% CI, 18.1-22.1] per 100 patient-years and 3.7 [95% CI, 2.0-5.3] vs 8.9 [95% CI, 7.8-10.0] per 100 patient-years, respectively; P < .001). Even after adjusting for demographic and clinical factors, the telemedicine cohort had a lower risk of hospital encounters (emergency department visits and admissions) with an adjusted incidence rate ratio of 0.57 (95% CI, 0.38-0.88) for all-cause encounters and an adjusted incidence rate ratio of 0.60 (95% CI, 0.36-0.99) for neurologic encounters. After matching on travel time to the neurology clinic, the adjusted incidence rate ratio was 0.19 (95% CI, 0.04-0.83) for all-cause admissions and 0.14 (95% CI, 0.02-0.82) for neurologic admissions. Conclusions and Relevance: Pediatric neurology care through real-time, audiovisual telemedicine consultations was associated with lower hospital utilization compared with in-person consultations, suggesting that high-cost hospital encounters can be prevented by improving subspecialty access.

CSF and Blood Levels of GFAP in Alexander Disease

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.

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.

The saccadic and neurological deficits in type 3 Gaucher disease.

UNLABELLED: 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. TRIAL REGISTRATION: ClinicalTrials.gov NCT00001289.

Free sialic acid storage disease without sialuria.

We performed high-resolution in vitro proton nuclear magnetic resonance spectroscopy on cerebrospinal fluid and urine samples of 44 patients with leukodystrophies of unknown cause. Free sialic acid concentration was increased in cerebrospinal fluid of two siblings with mental retardation and mild hypomyelination. By contrast, urinary excretion of free sialic acid in urine was normal on repeated testing by two independent methods. Both patients were homozygous for the K136E mutation in SLC17A5, the gene responsible for the free sialic acid storage diseases. Our findings demonstrate that mutations in the SLC17A5 gene have to be considered in patients with hypomyelination, even in the absence of sialuria.

Randomized, controlled trial of miglustat in Gaucher's disease type 3.

OBJECTIVE: To evaluate the efficacy and safety of miglustat, concomitant with enzyme replacement therapy (ERT), in patients with Gaucher's disease type 3 (GD3). METHODS: 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. RESULTS: 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. INTERPRETATION: 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 GD3.

Cognitive outcome in treated patients with chronic neuronopathic Gaucher disease.

OBJECTIVE: To investigate the spectrum and prevalence of cognitive deficits among children with type 3 (chronic neuronopathic) Gaucher disease (GD). STUDY DESIGN: A case review study identified 32 children (male/female; 17:15) with type 3 GD who had received enzyme replacement therapy (ERT) or a bone marrow transplant. The diagnosis of GD was established by enzymatic assay and DNA testing. Subjects were assessed with standard neuropsychological testing, and data from the most recent evaluation were included. RESULTS: Neuropsychometric assessments demonstrated a wide spectrum of full-scale IQ scores ranging from 39 to 124 (mean 75). About 60% of subjects had intellectual skills below average. There were significant discrepancies between verbal and performance IQ, with a range between -6 and 38 points (P = .02). This gap was more prominent in older subjects, with better performance in the verbal areas. No correlation was observed between intelligence measures and genotype or the extent of systemic involvement. The dosage, age at initiation, and the length of ERT had no significant effect on IQ scores. CONCLUSIONS: In type 3 GD, cognitive deficits, characterized by visual-spatial dysfunction, are common but underappreciated and appear resistant to ERT.

Isolated ocular disease is associated with decreased mucolipin-1 channel conductance.

PURPOSE: To evaluate a 15-year-old boy with MLIV (mucolipidosis type IV) and clinical abnormalities restricted to the eye who also had achlorhydria with elevated blood gastrin levels. METHODS: In addition to a detailed neuro-ophthalmic and electrophysiological assessment, his mutant mucolipin-1 was experimentally expressed in liposomes and its channel properties studied in vitro. RESULTS: The patient was a compound heterzygote for c.920delT and c.1615delG. Detailed neuro-ophthalmic examination including electroretinography showed him to have a typical retinal dystrophy predominantly affecting rod and bipolar cell function. In vitro expression of MCOLN1 in liposomes showed that the c.1615delG mutated channel had significantly reduced conductance compared with wild-type mucolipin-1, whereas the inhibitory effect of low pH and amiloride remained intact. CONCLUSIONS: These findings suggest that reduced channel conductance is relatively well tolerated by the brain during development, whereas retinal cells and stomach parietal cells require normal protein function. MLIV should be considered in patients with retinal dystrophy of unknown cause and screened for using blood gastrin levels.

Weekly enzyme replacement therapy may slow decline of renal function in patients with Fabry disease who are on long-term biweekly dosing.

This study was performed to determine whether adult male patients with Fabry disease who demonstrate a continuing decline in renal function despite 2 to 4 yr of conventionally dosed agalsidase alfa therapy (0.2 mg/kg every other week [EOW]) show an improved slope of decline with weekly administration using the same dosage. Eleven (27%) of 41 adult male patients with Fabry disease who participated in long-term agalsidase alfa clinical trials and who had demonstrated a slope of decline in estimated GFR (eGFR) of > or =5 ml/min per 1.73 m(2)/yr while receiving long-term treatment with agalsidase alfa at the currently recommended dosage of 0.2 mg/kg, infused EOW, were enrolled in this open-label, prospective study. Patients were switched from EOW to weekly infusions and followed for an additional 24 mo. Before switching to weekly dosing, eGFR was 53.7 +/- 6.3 ml/min per 1.73 m(2) (mean +/- SEM), and mean rate of change in eGFR was -8.0 +/- 0.8 ml/min per 1.73 m(2)/yr. During the 24-mo follow-up period after switching to weekly dosing, the mean rate of change in eGFR was observed to slow to -3.3 +/- 1.4 ml/min/1.73 m(2)/yr (P = 0.01 versus EOW). After switching to weekly dosing, three patients demonstrated an improvement in eGFR and six patients demonstrated a slowing in the rate of eGFR decline; only two patients failed to improve their eGFR slope. A multiple regression model confirmed that the weekly infusion regimen was the strongest explanatory variable for the change in eGFR (P = 0.0008), with a weaker contribution from the concomitant use of angiotensin converting enzyme inhibitors/angiotensin receptor blockers (P = 0.02). These results suggest that weekly infusions of agalsidase alfa at a dosage of 0.2 mg/kg may be beneficial in the subgroup of patients who have Fabry disease and whose kidney function continues to decline after 2 to 4 yr or more of standard EOW dosing.