Tyrosinemia type II

Tyrosinemia type II (also known as Richner-Hanhart syndrome) is a rare metabolic disorder characterized by elevated blood levels of the amino acid tyrosine, a building block of most proteins. This condition is classified as a type of aminoaciduria.

Signs and Symptoms

People with Tyrosinemia type II often develop painful skin lesions on the palms of their hands and soles of their feet, a condition known as palmoplantar keratoderma. They may also have eye abnormalities, including corneal ulcers and inflammation. Some affected individuals have intellectual disability or developmental delay, but these problems are less common.

Causes

Tyrosinemia type II is caused by mutations in the TAT gene. This gene provides instructions for making an enzyme called tyrosine aminotransferase, which is involved in the multi-step process that breaks down tyrosine. Mutations in the TAT gene reduce or eliminate the activity of tyrosine aminotransferase, preventing the normal breakdown of tyrosine. As a result, this amino acid can build up in the blood and other tissues and damage the skin, eyes, and nervous system.

Diagnosis

Diagnosis of Tyrosinemia type II is often suspected based on the presence of characteristic signs and symptoms. Specialized tests can measure the levels of tyrosine in the blood and confirm a diagnosis.

Treatment

Treatment for Tyrosinemia type II typically involves a diet low in tyrosine and phenylalanine. This diet can help reduce the symptoms of the disorder, but it does not cure the disease. In some cases, additional treatments may be necessary.

See also

• Tyrosinemia
• Aminoaciduria
• Metabolic disorder

References

Tyrosinemia type II Resources
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