Carnosinaemia

**Definition:** Carnosinaemia is a very rare inherited disorder of the metabolism of peptides that presents with serum carnosinase deficiency, variable degrees of intellectual deficit, sometimes with seizures, while a few patients are asymptomatic.

**Long definition:** Carnosinemia is a very rare inherited disorder that presents with serum carnosinase deficiency. The gene associated with this disease has not been identified. Autosomal recessive inheritance has been suggested. About 30 individuals have been reported worldwide. The majority of the patients showed variable degrees of intellectual deficit. Some patients had seizures and one had congenital myopathy. A few patients had no symptoms at all. Diagnosis is based on amino acid analysis of serum and/or urine after exclusion of meat from the diet, and enzymatic testing. The differential diagnosis includes gamma-amino butyric acid (GABA) transaminase deficiency. No efficient treatment is available, and it remains uncertain whether treatment is necessary.