UNASSIGNED: Alexander disease is caused by mutations in GFAP, the glial fibrillary acidic protein gene. External laryngeal tremor has not been reported in adult-onset Alexander disease (AOAxD). The aims of this work were to report one such case and to review the literature on palatopharyngeal tremor and AOAxD.
UNASSIGNED: A 43-year-old man experienced involuntary movements at the front of his neck. Continuous, rhythmic vertical movements of the laryngeal skeleton, soft palate and tongue, and lower limb dysmetria were observed. The pathogenic GFAP variant c.994G>A; p.(Glu332Lys) was found. MRI demonstrated spinal cord and medulla oblongata atrophy and hyperintensities at the cerebellum and cerebral white matter.
UNASSIGNED: External laryngeal, palatopharyngeal tremor and cerebellar ataxia constituted a mild phenotype, as expected from this variant, herein reported in isolation for the third time. Imaging was consistent with AOAxD, including the so-called tadpole sign. Additional studies are necessary to define this infrequent disease.

Neurodegenerative diseases are a diverse group of diseases characterized by a progressive loss of neurological function due to damage to nerve cells in the central nervous system. In recent years, there has been a worldwide increase in the expanding associated with increasing human life expectancy. Molecular mechanisms control many of the essential life processes of cells, such as replication, transcription, translation, protein synthesis and gene regulation. These are complex interactions that form the basis for understanding numerous processes in the organism and developing new diagnostic and therapeutic approaches. In the context of neurodegenerative diseases, molecular basis refers to changes at the molecular level that cause damage to or degeneration of nerve cells. These may include protein aggregates leading to pathological structures in brain cells, impaired protein transport in nerve cells, mitochondrial dysfunction, inflammatory processes or genetic mutations that impair nerve cell function. New medical therapies are based on these mechanisms and include gene therapies, reduction in inflammation and oxidative stress, and the use of miRNAs and regenerative medicine. The aim of this study was to bring together the current state of knowledge regarding selected neurodegenerative diseases, presenting the underlying molecular mechanisms involved, which could be potential targets for new forms of treatment.

BACKGROUND: Alexander disease is a rare, progressive leukodystrophy, which predisposes patients to complications under general anesthesia due to clinical manifestations including developmental delay, seizures, dysphagia, vomiting, and sleep apnea. However, study of anesthetic outcomes is limited.
OBJECTIVE: Our aim was to describe patient characteristics, anesthetic techniques, and anesthesia-related complications for Alexander disease patients undergoing magnetic resonance imaging and/or lumbar puncture at a quaternary-care children\'s hospital.
METHODS: We performed a retrospective review of anesthetic outcomes in patients with Alexander disease enrolled in a prospective observational study. Included patients had diagnosed Alexander disease and underwent magnetic resonance imaging and/or lumbar puncture at our institution. We excluded anesthetics for other procedures or at outside institutions. Collected data included patient characteristics, anesthetic techniques, medications, and complications under anesthesia and in the subsequent 24 h. We performed descriptive statistics as appropriate.
RESULTS: Forty patients undergoing 64 procedures met inclusion criteria. Fifty-six procedures (87.5%) required general anesthesia or monitored anesthesia care (MAC) and eight (12.5%) did not. The general anesthesia/MAC group tended to be younger than nonanesthetized patients (median age 6 years [IQR 3.8; 9] vs. 14.5 years [IQR 12.8; 17.5]). In both groups, dysphagia (78.6% vs. 87.5%, respectively), seizures (62.5% vs. 25%), and recurrent vomiting (17.9% vs. 25%) were frequently reported preprocedure symptoms. Inhalational induction was common (N = 48; 85.7%), and two (3.6%) underwent rapid sequence induction. Serious complications were rare, with no aspiration or seizures. Hypotension resolving with ephedrine occurred in eight cases (14.3%). One patient each (1.8%) experienced postprocedure emergence agitation or vomiting. Fifty-three (94.6%) were ambulatory procedures. No inpatients required escalation in acuity of care.
CONCLUSIONS: In this single-center study, patients with Alexander disease did not experience frequent or irreversible complications while undergoing general anesthesia/MAC. Co-morbid symptoms were not increased postanesthesia. Some patients may not require anesthesia to complete short procedures.

Here, we describe pathological events potentially involved in the disease pathogenesis of Alexander disease (AxD). This is a primary genetic disorder of astrocyte caused by dominant gain-of-function mutations in the gene coding for an intermediate filament protein glial fibrillary acidic protein (GFAP). Pathologically, this disease is characterized by the upregulation of GFAP and its accumulation as Rosenthal fibers. Although the genetic basis linking GFAP mutations with Alexander disease has been firmly established, the initiating events that promote GFAP accumulation and the role of Rosenthal fibers (RFs) in the disease process remain unknown. Here, we investigate the hypothesis that disease-associated mutations promote GFAP aggregation through aberrant posttranslational modifications. We found high molecular weight GFAP species in the RFs of AxD brains, indicating abnormal GFAP crosslinking as a prominent pathological feature of this disease. In vitro and cell-based studies demonstrate that cystine-generating mutations promote GFAP crosslinking by cysteine-dependent oxidation, resulting in defective GFAP assembly and decreased filament solubility. Moreover, we found GFAP was ubiquitinated in RFs of AxD patients and rodent models, supporting this modification as a critical factor linked to GFAP aggregation. Finally, we found that arginine could increase the solubility of aggregation-prone mutant GFAP by decreasing its ubiquitination and aggregation. Our study suggests a series of pathogenic events leading to AxD, involving interplay between GFAP aggregation and abnormal modifications by GFAP ubiquitination and oxidation. More important, our findings provide a basis for investigating new strategies to treat AxD by targeting abnormal GFAP modifications.

While classic brain MR imaging features of Alexander disease have been well-documented, lesional patterns can overlap with other leukodystrophies, especially in the early stages of the disease or in milder phenotypes. We aimed to assess the utility of a new neuroimaging sign to help increase the diagnostic specificity of Alexander disease.
A peculiar bilateral symmetric hyperintense signal on T2-weighted images affecting the medulla oblongata was identified in an index patient with type I Alexander disease. Subsequently, 5 observers performed a systematic MR imaging review for this pattern by examining 55 subjects with Alexander disease and 74 subjects with other leukodystrophies. Interobserver agreement was assessed by the κ index. Sensitivity, specificity, and receiver operating characteristic curves were determined.
The identified pattern was present in 87% of subjects with Alexander disease and 14% of those without Alexander disease leukodystrophy (P < .001), 3 with vanishing white matter, 4 with adult polyglucosan body disease, and 3 others. It was found equally in both type I and type II Alexander disease (28/32, 88% versus 18/21, 86%; P = .851) and in subjects with unusual disease features (2/2). Sensitivity (87.3%; 95% CI, 76.0%-93.7%), specificity (86.5%; 95% CI, 76.9%-92.5%), and interobserver agreement (κ index = 0.82) were high.
The identified pattern in the medulla oblongata, called the chipmunk sign due to its resemblance to the face of this rodent, is extremely common in subjects with Alexander disease and represents a diagnostic tool that can aid in early diagnosis, especially in subjects with otherwise atypical MR imaging findings and/or clinical features.

This report presents a case of Alexander disease showing clinical characteristics mimicking progressive supranuclear palsy (PSP). A 67-year-old woman complaining of motor disturbance exhibited severe atrophy of medulla, spinal cord, and midbrain tegmentum, as well as periventricular hyperintensity on cerebral MRI. Genetic analysis identified a novel in-frame deletion/insertion mutation in the exon 3 of the GFAP gene. Interestingly, neurological findings and decreased striatal uptake in dopamine transporter SPECT were suggestive of PSP. A novel GFAP gene mutation found in the present case may cause the unique clinical phenotype, which should be differentiated from PSP.

Alexander disease (AxD) is a rare inherited autosomal dominant (AD) disease with different clinical phenotypes according to the age of onset. It is caused by mutations in the glial fibrillary acid protein (GFAP) gene, which causes GFAP accumulation in astrocytes. A wide spectrum of mutations has been described. For some variants, genotype-phenotype correlations have been described, although variable expressivity has also been reported in late-onset cases among members of the same family. We present the case of a 19-year-old girl who developed gait ataxia and subtle involuntary movements, preceded by a history of enuresis and severe scoliosis. Her mother has been affected by ataxia since her childhood, which was then complicated by pyramidal signs and heavily worsened through the years. Beyond her mother, no other known relatives suffered from neurologic syndromes. The scenario was further complicated by a complex brain and spinal cord magnetic resonance imaging (MRI) pattern in both mother and daughter. However, the similar clinical phenotype made an inherited cause highly probable. Both AD and autosomal recessive (AR) ataxic syndromes were considered, lacking a part of the proband\'s pedigree, but no causative genetic alterations were found. Considering the strong suspicion for an inherited condition, we performed clinical exome sequencing (CES), which analyzes more than 4,500 genes associated with diseases. CES evidenced the new heterozygous missense variant c.260 T > A in exon 1 of the glial fibrillary acidic protein (GFAP) gene (NM_002055.4), which causes the valine to aspartate amino acid substitution at codon 87 (p. Val87Asp) in the GFAP. The same heterozygous variant was detected in her mother. This mutation has never been described before in the literature. This case should raise awareness for this rare and under-recognized disease in juvenile-adult cases.

BACKGROUND: Alexander disease (AxD) is a rare leukodystrophy caused by dominant gain-of-function mutations in the gene encoding the astrocyte intermediate filament, glial fibrillary acidic protein (GFAP). However, there is an urgent need for biomarkers to assist in monitoring not only the progression of disease but also the response to treatment. GFAP is the obvious candidate for such a biomarker, as it is measurable in body fluids that are readily accessible for biopsy, namely cerebrospinal fluid and blood. However, in the case of ASOs, the treatment that is furthest in development, GFAP is the target of therapy and presumably would go down independent of disease status. Hence, there is a critical need for biomarkers that are not directly affected by the treatment strategy.
METHODS: We explored the potential utility of biomarkers currently being studied in other neurodegenerative diseases and injuries, specifically neurofilament light protein (NfL), phosphorylated forms of tau, and amyloid-β peptides (Aβ42/40).
CONCLUSIONS: Here, we report that GFAP is elevated in plasma of all age groups afflicted by AxD, including those with adult onset. NfL and p-tau are also elevated, but to a much lesser extent than GFAP. In contrast, the levels of Aß40 and Aß42 are not altered in AxD.

Alexander disease (AxD) is a rare neurodegenerative condition that represents the group of leukodystrophies. The disease is caused by GFAP mutation. Symptoms usually occur in the infantile age with macrocephaly, developmental deterioration, progressive quadriparesis, and seizures as the most characteristic features. In this case report, we provide a detailed clinical description of the neonatal type of AxD.
Next-Generation Sequencing (NGS), including a panel of 49 genes related to Early Infantile Epileptic Encephalopathy (EIEE), was carried out, and then Whole Exome Sequencing (WES) was performed on the proband\'s DNA extracted from blood.
In the first weeks of life, the child presented with signs of increased intracranial pressure, which led to ventriculoperitoneal shunt implementation. Recurrent focal-onset motor seizures with secondary generalization occurred despite phenobarbital treatment. Therapy was modified with multiple anti-seizure medications. In MRI contrast-enhanced lesions in basal ganglia, midbrain and cortico-spinal tracts were observed. During the diagnostic process, GLUT-1 deficiency, lysosomal storage disorders, organic acidurias, and fatty acid oxidation defects were excluded. The NGS panel of EIEE revealed no abnormalities. In WES analysis, GFAP missense heterozygous variant NM_002055.5: c.1187C>T, p.(Thr396Ile) was detected, confirming the diagnosis of AxD.
AxD should be considered in the differential diagnosis in all neonates with progressive, intractable seizures accompanied by macrocephaly.

The majority of the population of glial cells in the central nervous system consists of astrocytes, and impairment of astrocytes causes various disorders. It is useful to assess the multiple astrocytic properties in order to understand their complex roles in the pathophysiology. Although we can differentiate human astrocytes from induced pluripotent stem cells (iPSCs), it remains unknown how we can analyse and reveal the multiple properties of astrocytes in complexed human disease conditions. For this purpose, we tested astrocytic differentiation protocols from feeder-free iPSCs based on the previous method with some modifications. Then, we set up extra- and intracellular assessments of iPSC-derived astrocytes by testing cytokine release, calcium influx, autophagy induction and migration. The results led us to analytic methods with conditions in which iPSC-derived astrocytes behave as in vivo. Finally, we applied these methods for modelling an astrocyte-related disease, Alexander disease. An analytic system using iPSC-derived astrocytes could be used to recapture complexities in human astrocyte diseases.