A Novel Mutation in the Adult-Onset Alexander's Disease GFAP Gene

Case report: Alexander's disease with "head drop" as the main symptom and literature review

Alexander's disease (AxD) is a rare autosomal dominant hereditary disorder that is caused by the mutations in the GFAP gene, which encodes the glial fibrillary acidic protein (GFAP). This neurogenerative disease has many clinical manifestations, and the onset of disease spans a wide range of ages, from newborns to children, adults, and even the elderly. An overaccumulation of the expression of GFAP has a close causal relationship with the pathogenesis of Alexander's disease. Usually, the disease has severe morbidity and high mortality, and can be divided into three distinct subgroups that are based on the age of clinical presentation: infantile (0-2 years), juvenile (2-13 years), and adult (>13 years). Children often present with epilepsy, macrocephaly, and psychomotor retardation, while adolescents and adults mainly present with muscle weakness, spasticity, and bulbar symptoms. Atonic seizures are a type of epilepsy that often appears in the Lennox-Gastaut syndrome and myoclonic-astatic epilepsy in early childhood; however, the prognosis is often poor. Atonic episodes are characterized by a sudden or frequent reduction in muscle tone that can be local (such as head, neck, or limb) or generalized. Here, we report a 4-year-old girl whose main symptoms were intermittent head drop movements, which could break the frontal frame and even bleed in severe conditions. A video-encephalography (VEEG) showed that the nodding movements were atonic seizures. A head magnetic resonance imaging (MRI) revealed abnormal signals in the bilateral paraventricular and bilateral subfrontal cortex. The gene detection analyses indicated that the GFAP gene exon 1 c.262 C>T was caused by a heterozygous mutation, as both her parents were of the wild-type. The girl had no other abnormal manifestations except atonic seizures. She could communicate normally and go to kindergarten. After an oral administration of sodium valproate, there were no atonic attacks. Although epilepsy is a common symptom of Alexander's disease, atonic seizures have not been reported to date. Therefore, we report a case of Alexander's disease with atonic seizures as the main symptom and provide a review of the literature.

Identification of a novel de novo pathogenic variant in GFAP in an Iranian family with Alexander disease by whole-exome sequencing

Background

Alexander disease (AxD) is a rare leukodystrophy with an autosomal dominant inheritance mode. Variants in GFAP lead to this disorder and it is classified into three distinguishable subgroups: infantile, juvenile, and adult-onset types.

Objective

The aim of this study is to report a novel variant causing AxD and collect all the associated variants with juvenile and adult-onset as well.

Methods

We report a 2-year-old female with infantile AxD. All relevant clinical and genetic data were evaluated. Search strategy for all AxD types was performed on PubMed. The extracted data include total recruited patients, number of patients carrying a GFAP variant, nucleotide and protein change, zygosity and all the clinical symptoms.

Results

A novel de novo variant c.217A > G: p. Met73Val was found in our case by whole-exome sequencing. In silico analysis categorized this variant as pathogenic. Totally 377 patients clinically diagnosed with juvenile or adult-onset forms were recruited in these articles, among them 212 patients were affected with juvenile or adult-onset form carrier of an alteration in GFAP. A total of 98 variants were collected. Among these variants c.262C > T 11/212 (5.18%), c.1246C > T 9/212 (4.24%), c.827G > T 8/212 (3.77%), c.232G > A 6/212 (2.83%) account for the majority of reported variants.

Conclusion

This study highlighted the role of genetic in AxD diagnosing. It also helps to provide more information in order to expand the genetic spectrum of Iranian patients with AxD. Our literature review is beneficial in defining a better genotype–phenotype correlation of AxD disorder.

Psychiatric Onset Alexander Disease: An Important Challenge in Neuropsychiatric Diagnosis: A Case Report

INTRODUCTION

Alexander disease is a heterogeneous group of diseases with various manifestations based on the age of disease onset. This rare leukodystrophy syndrome with mutations in the GFAP gene could present with developmental delay and seizure in the infantile form to ataxia and bulbar palsy in adulthood. However, psychiatric symptoms are not well-defined and are usually evaluated after disease diagnosis, not before disease investigations.

CASE REPORT

Our patient is a 52-year-old Iranian woman with a history of depression since 17 years ago, a suicidal attempt two years ago, and ingestion of a large amount of opium with the intention of suicide 2 months ago. She was presented with disorientation and probably a delirious state in the last interview. Eventually, in comprehensive investigations, white matter hyperintensity in MRI and leukodystrophy was diagnosed to determine the cause of these changes, we did a gene study, found whole exon deletion of the GFAP gene, and made a diagnosis of late-onset Alexander disease.

CONCLUSION

Neurological-onset manifestation of Alexander disease, specifically late-onset form, is the most common clinical picture of disease and was seen in about 90% of patients, but psychiatric symptoms are not well-known, and psychiatric-onset disease was not described yet. Various gene mutations were described in late-onset Alexander disease; however, the large whole exon deletion which was revealed in our patient is a novel mutation and significantly needs to be explored. Here authors describe a late-onset Alexander disease with psychiatric-onset symptoms and novel large exon deletion in the GFAP gene.

HIGHLIGHTS

Alexander disease is a rare heterogeneous disorder that could have various symptoms of the central nervous system involvement.The whole-exons deletion of the GFAP gene in an adult patient with features of Alexander disease is the first Gene mutation that was revealed in this case.Psychiatric onset Alexander disease is the one differential diagnosis in the patients with atypical psychiatric symptoms combined with soft neurological signs.Neurologic consultation and appropriate imaging and laboratory procedures could help early diagnosis and potential treatment.

PLAIN LANGUAGE SUMMARY

Patients with atypical psychiatric symptoms are usually visited more times in the year without any significant benefit. They receive numerous medications and encounter significant complications due to mentioned polypharmacy. However, genetic, metabolic, or neurological causes could be considered in some treatment-resistant cases. We described the rare genetic disorder(Late-Onset Alexander disease) in the Iranian woman with atypical and treatment-resistant depression with suicidal attempts. We proposed holistic assessment in the patients with psychiatric symptoms which have atypical course or response to treatment or are accompanied by neurological and cognitive symptoms.