Peroxisomal disorder

Overview

Diagram of a peroxisome

A peroxisomal disorder is a type of metabolic disorder that results from dysfunctions in the peroxisome, an organelle found in virtually all eukaryotic cells. Peroxisomes play a crucial role in the metabolism of lipids and the detoxification of reactive oxygen species. Disorders of peroxisomes can lead to a wide range of clinical manifestations, often affecting multiple organ systems.

Function of Peroxisomes

Peroxisomes are involved in several key metabolic pathways, including the beta-oxidation of very long chain fatty acids, the biosynthesis of plasmalogens, and the detoxification of hydrogen peroxide. They also play a role in the metabolism of bile acids and the synthesis of cholesterol.

Classification

Peroxisomal disorders can be classified into two main categories:

Peroxisome Biogenesis Disorders (PBDs)

PBDs are caused by defects in the assembly of peroxisomes. The most well-known PBD is Zellweger syndrome, which is characterized by severe neurological impairment, liver dysfunction, and craniofacial abnormalities.

Single Enzyme Deficiencies

These disorders result from the deficiency of a single peroxisomal enzyme. Examples include X-linked adrenoleukodystrophy and Refsum disease.

Clinical Manifestations

The clinical presentation of peroxisomal disorders can vary widely, but common features include:

• Neurological symptoms such as hypotonia, seizures, and developmental delay.
• Liver dysfunction leading to hepatomegaly and jaundice.
• Skeletal abnormalities and craniofacial dysmorphism.
• Vision and hearing impairments.

Diagnosis

Diagnosis of peroxisomal disorders typically involves a combination of clinical evaluation, biochemical tests, and genetic testing. Biochemical tests may include the measurement of very long chain fatty acids, plasmalogens, and bile acid intermediates in the blood.

Treatment

Currently, there is no cure for peroxisomal disorders, and treatment is primarily supportive. Management may include dietary modifications, physical therapy, and symptomatic treatment for seizures and other complications.

Research and Future Directions

Research into peroxisomal disorders is ongoing, with efforts focused on understanding the molecular mechanisms underlying these conditions and developing potential therapies. Gene therapy and enzyme replacement therapy are areas of active investigation.

Related Pages

• Zellweger syndrome
• X-linked adrenoleukodystrophy
• Refsum disease
• Metabolic disorder