18-Hydroxylase deficiency

18-Hydroxylase deficiency is a rare endocrine disorder that affects the production of aldosterone by the adrenal glands. Aldosterone is a hormone crucial for sodium retention, potassium excretion, and maintaining blood pressure. This condition is part of a group of disorders known as congenital adrenal hyperplasia (CAH), which involves a deficiency of enzymes necessary for the production of adrenal steroid hormones.

Causes

18-Hydroxylase deficiency is caused by mutations in the CYP11B2 gene, which encodes the enzyme 18-hydroxylase. This enzyme is involved in the final steps of aldosterone synthesis. The mutations lead to reduced or absent enzyme activity, resulting in decreased aldosterone production.

Symptoms

The symptoms of 18-Hydroxylase deficiency can vary but often include:

• Salt-wasting crises in infancy due to the body's inability to retain sodium
• Hypotension (low blood pressure)
• Hyperkalemia (elevated blood potassium levels)
• Failure to thrive in infants
• Dehydration
• Metabolic acidosis

Diagnosis

Diagnosis of 18-Hydroxylase deficiency involves a combination of clinical evaluation, biochemical tests, and genetic testing. Biochemical tests typically show low aldosterone levels, high plasma renin activity, and potentially abnormal levels of sodium and potassium. Genetic testing can confirm mutations in the CYP11B2 gene.

Treatment

Treatment focuses on correcting the hormone deficiencies and managing symptoms. This usually involves:

• Corticosteroid replacement to compensate for the lack of aldosterone
• Salt supplements, especially in infants and children, to help retain sodium
• Monitoring and managing potassium levels to prevent hyperkalemia

Prognosis

With early diagnosis and appropriate treatment, individuals with 18-Hydroxylase deficiency can lead normal, healthy lives. However, ongoing monitoring and treatment adjustments are often necessary.

See also

• Congenital adrenal hyperplasia
• Adrenal insufficiency
• Hyperkalemia
• Hypotension