Neurobehavioral characterization of adult-onset Alexander disease: A family study

Adult Hereditary White Matter Diseases With Psychiatric Presentation: Clinical Pointers and MRI Algorithm to Guide the Diagnostic Process

OBJECTIVE

The investigators aimed to provide clinical and MRI guidelines for determining when genetic workup should be considered in order to exclude hereditary leukoencephalopathies in affected patients with a psychiatric presentation.

METHODS

A systematic literature review was conducted, and clinical cases are provided. Given the central role of MRI pattern recognition in the diagnosis of white matter disorders, the investigators adapted an MRI algorithm that guides the interpretation of MRI findings and thus directs further investigations, such as genetic testing.

RESULTS

Twelve genetic leukoencephalopathies that can present with psychiatric symptoms were identified. As examples of presentations that can occur in clinical practice, five clinical vignettes from patients assessed at a referral center for adult genetic leukoencephalopathies are provided.

CONCLUSIONS

Features such as drug-resistant symptoms, presence of long-standing somatic features, trigger events, consanguinity, and positive family history should orient the clinician toward diagnostic workup to exclude the presence of a genetic white matter disorder. The identification of MRI white matter abnormalities, especially when presenting a specific pattern of involvement, should prompt genetic testing for known forms of genetic leukoencephalopathies.

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.

Does genetic anticipation occur in familial Alexander disease?

Alexander Disease (AxD) is a rare leukodystrophy caused by missense mutations of glial fibrillary acidic protein (GFAP). Primarily seen in infants and juveniles, it can present in adulthood. We report a family with inherited AxD in which the mother presented with symptoms many years after her daughter. We reviewed the age of onset in all published cases of familial AxD and found that 32 of 34 instances of parent–offspring pairs demonstrated an earlier age of onset in offspring compared to the parent. We suggest that genetic anticipation occurs in familial AxD and speculate that genetic mosaicism could explain this phenomenon.