Carnosinemia

Symptoms and signs

A variety of neurological symptoms have been associated with carnosinemia. They include: hypotonia, developmental delay, intellectual disability, degeneration of axons, sensory neuropathy, tremors, demyelinization, gray matter anomalies, myoclonic seizures, and loss of purkinje fibers.

Genetics

The gene for carnosinase is located on chromosome 18, Mutations in CNDP1 are responsible for carnosinase deficiency, resulting in carnosinemia.

Carnosinemia is an autosomal recessive disorder, which means the defective gene is located on an autosome, and two copies of the defective gene - one from each parent - are required to inherit the disorder. The parents of an individual with an autosomal recessive disorder both carry one copy of the defective gene, but usually do not experience any signs or symptoms of the disorder.

Diagnosis

Types

Carnosinase in humans has two forms:

1. Cellular, or tissue carnosinase: based in part on its ability to hydrolyze a range of dipeptide substrates, including those belonging to prolinase.

2. Serum carnosinase: Serum carnosinase is a glycoprotein, and splits free carnosine and anserine in the blood.

A deficiency of tissue and serum carnosinase, with serum being an indicator, is the underlying metabolic cause of carnosinemia.

Treatment

There is currently no cure for carnosinemia, but treatment focuses on managing symptoms and preventing complications. A strict meat-free diet can help with symptoms, but it will not cure the disease. Carnosinemia patients and their families should seek genetic counseling.

References

References

1. {{OMIM. 212200
2. {{DiseasesDB. 29672
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16. (1969). "A patient with a deficiency of serum-carnosinase activity". Acta Paediatr. Scand..
17. (1983). "Homocarnosinosis: lack of serum carnosinase is the deficiency probably responsible for elevated brain and CSF homocarnosine". Clin Chim Acta.