Alexander Disease *

Alexander Disease *

Introduction

Alexander disease* is a very rare autosomal dominant leukodystrophy, which are neurological conditions caused by anomalies in the myelin which protects nerve fibers in the brain. The most common type is the infantile form that usually begins during the first 2 years of life. Symptoms include mental and physical developmental delays, followed by the loss of developmental milestones, an abnormal increase in head size and seizures. The juvenile form of Alexander disease has an onset between the ages of 2 and 13 years. These children may have excessive vomiting, difficulty swallowing and speaking, poor coordination, and loss of motor control. Adult-onset forms of Alexander disease are less common. The symptoms sometimes mimic those of Parkinson’s disease or multiple sclerosis, or may present primarily as a psychiatric disorder.

According to the National Institute of Neurological Disorders and Stroke, the destruction of white matter is accompanied by the formation of Rosenthal fibers—abnormal clumps of protein that accumulate in astrocytes in the brain.

The disease occurs in both males and females, and no ethnic, racial, geographic or cultural/economic differences are seen in its distribution. Alexander disease is a progressive and often fatal disease.

Symptoms

Type I form include a failure to grow and gain weight at the expected rate (failure to thrive); delays in the development of certain physical, mental, and behavioral skills that are typically acquired at particular stages (psychomotor impairment); and sudden episodes of uncontrolled electrical activity in the brain (seizures). Additional features typically include progressive enlargement of the head (macrocephaly); abnormally increased muscle stiffness and restriction of movement (spasticity); lack of coordination (ataxia); and vomiting and difficulty swallowing, coughing, breathing or talking (bulbar and pseudobulbar signs). Nearly 90% of infantile patients display developmental problems and seizures, and over 50% the other symptoms mentioned; however, no single symptom or combination of symptoms is always present.

Type II Alexander disease rarely show delay or regression of development, macrocephaly or seizures, and mental decline may develop slowly or not at all. Instead, about 50% display bulbar/pseudobulbar signs, about 75% have ataxia and about 33% spasticity. Because these symptoms are not specific, adult Alexander disease is sometimes confused with more common disorders such as multiple sclerosis or the presence of tumors.

Causes

Mutations in GFAP gene. It is inherited in an autosomal recessive manner, such that the child of a parent with the disease has a 50% chance of inheriting the condition, if the parent is heterozygotic. However, most cases arise de novo as the result of sporadic mutations.

Prevalence

1:2’000’000

Additional Information

Support provided by Metabolic UK – https://www.metabolicsupportuk.org/wp-content/uploads/2017/04/Alexander-Disease.pdf

Clinical trial for Alexander disease (Type I and II) in the United States: Clinical trial, Alexander disease

 

*We run research program into this condition.

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Last Updated on 9 July 2021