2-Hydroxyglutaric aciduria

2-Hydroxyglutaric Aciduria

Structure of 2-hydroxyglutaric acid

2-Hydroxyglutaric aciduria is a rare metabolic disorder characterized by the accumulation of 2-hydroxyglutaric acid in the urine. This condition is caused by defects in the metabolic pathways that process 2-hydroxyglutarate, leading to its accumulation in the body.

Classification

2-Hydroxyglutaric aciduria is classified into three main types based on the specific form of 2-hydroxyglutarate that accumulates:

• L-2-hydroxyglutaric aciduria
• D-2-hydroxyglutaric aciduria
• Combined D-2- and L-2-hydroxyglutaric aciduria

Each type is associated with different genetic mutations and clinical manifestations.

Genetics

Autosomal recessive inheritance pattern

2-Hydroxyglutaric aciduria is inherited in an autosomal recessive pattern. This means that an individual must inherit two copies of the defective gene, one from each parent, to manifest the disorder. The specific genes involved vary depending on the type of 2-hydroxyglutaric aciduria:

• L-2-hydroxyglutaric aciduria is caused by mutations in the L2HGDH gene.
• D-2-hydroxyglutaric aciduria is associated with mutations in the D2HGDH gene or the IDH2 gene.
• Combined D-2- and L-2-hydroxyglutaric aciduria involves mutations in the SLC25A1 gene.

Pathophysiology

The accumulation of 2-hydroxyglutarate interferes with normal cellular metabolism. It is believed to affect the function of enzymes involved in the Krebs cycle, leading to impaired energy production and other metabolic disturbances. The exact mechanisms by which 2-hydroxyglutarate causes damage to the central nervous system and other tissues are still under investigation.

Clinical Features

Patients with 2-hydroxyglutaric aciduria may present with a variety of symptoms, including:

• Developmental delay
• Seizures
• Hypotonia
• Ataxia
• Macrocephaly

The severity and range of symptoms can vary widely among affected individuals.

Diagnosis

Diagnosis of 2-hydroxyglutaric aciduria is typically made through the detection of elevated levels of 2-hydroxyglutarate in the urine, blood, or cerebrospinal fluid. Genetic testing can confirm the diagnosis by identifying mutations in the relevant genes.

Treatment

There is currently no cure for 2-hydroxyglutaric aciduria. Treatment is primarily supportive and symptomatic, focusing on managing seizures and other neurological symptoms. Dietary modifications and supplements may be recommended in some cases.

Prognosis

The prognosis for individuals with 2-hydroxyglutaric aciduria varies depending on the type and severity of the condition. Some individuals may experience significant neurological impairment, while others may have milder symptoms.

Related Pages

• Metabolic disorder
• Autosomal recessive disorder
• Krebs cycle