Aminolevulinic acid dehydratase deficiency porphyria

A rare metabolic disorder affecting heme biosynthesis

Aminolevulinic acid dehydratase deficiency porphyria (ALAD porphyria) is a rare metabolic disorder that affects the heme biosynthesis pathway. It is characterized by a deficiency in the enzyme aminolevulinic acid dehydratase (ALAD), which leads to the accumulation of aminolevulinic acid (ALA) in the body. This condition is one of the types of porphyria, a group of disorders caused by abnormalities in the chemical steps leading to the production of heme.

Pathophysiology

The enzyme aminolevulinic acid dehydratase is crucial in the second step of the heme biosynthesis pathway. It catalyzes the conversion of two molecules of aminolevulinic acid into porphobilinogen. In ALAD porphyria, the deficiency of this enzyme results in the accumulation of ALA, which is neurotoxic and leads to the clinical manifestations of the disease.

Clinical Features

Patients with ALAD porphyria typically present with a variety of symptoms, which may include:

• Severe abdominal pain
• Neuropathy
• Vomiting
• Hypertension
• Seizures
• Psychiatric symptoms such as anxiety and depression

The symptoms are often triggered by factors such as certain medications, alcohol, fasting, or stress.

Diagnosis

The diagnosis of ALAD porphyria is based on clinical presentation and laboratory tests. Key diagnostic tests include:

• Measurement of ALA levels in urine, which are typically elevated.
• Enzyme assay to determine ALAD activity in red blood cells.
• Genetic testing to identify mutations in the ALAD gene.

Treatment

Management of ALAD porphyria involves:

• Avoidance of triggering factors such as certain drugs and alcohol.
• Administration of glucose or hemin to reduce ALA production.
• Supportive care for symptoms such as pain management and treatment of hypertension.

Prognosis

The prognosis of ALAD porphyria varies depending on the severity of the enzyme deficiency and the effectiveness of management strategies. With appropriate treatment and avoidance of triggers, many patients can lead relatively normal lives.

Related pages

• Porphyria
• Heme
• Metabolic disorder
• Neuropathy