Hyperlysinemia

Hyperlysinemia is a rare, inherited metabolic disorder characterized by an excess of the amino acid lysine in the blood. It is caused by a deficiency of the enzyme that breaks down lysine. Most individuals with hyperlysinemia do not exhibit symptoms, but some may experience seizures, intellectual disability, or behavioral problems.

Causes

Hyperlysinemia is caused by a deficiency of the enzyme lysine-ketoglutarate reductase or saccharopine dehydrogenase, which are involved in the breakdown of lysine. This deficiency is due to mutations in the AASS gene. The disorder is inherited in an autosomal recessive manner, meaning both copies of the gene in each cell have mutations.

Symptoms

Most individuals with hyperlysinemia do not exhibit symptoms. However, some may experience seizures, intellectual disability, or behavioral problems. The severity of symptoms can vary widely among affected individuals.

Diagnosis

Hyperlysinemia is diagnosed through a blood test that measures the levels of amino acids in the blood. High levels of lysine and sometimes other amino acids can indicate hyperlysinemia. Genetic testing can also be used to identify mutations in the AASS gene.

Treatment

There is currently no cure for hyperlysinemia. Treatment is symptomatic and supportive, and may include dietary restrictions of lysine and medications to manage seizures.

Prognosis

The prognosis for individuals with hyperlysinemia varies. Some individuals may remain asymptomatic throughout their lives, while others may experience neurological symptoms such as seizures and intellectual disability.

See also

• Amino acid disorder
• Metabolic disorder
• Inborn errors of metabolism

References

Hyperlysinemia Resources
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