Lysinuric protein intolerance (lysinuria) is a rare and severe inherited metabolic disorder that results in a disorder of the metabolism of three specific amino acids – lysine, arginine and ornithine. This defect is caused by mutations in the SLC7A7 gene, which codes for part of the transport protein responsible for the removal of these amino acids from cells.
History of the disease and interesting historical facts
The disease was originally described in 1965 by Italian doctors who found abnormal levels of lysine, arginine and ornithine in the urine of patients with unexplained symptoms including growth retardation and mental retardation. It was therefore decided to call the disease "lysinuric protein intolerance".
Epidemiology
Lysinuric protein intolerance is a very rare disease with an incidence of less than one case in 60,000 births, although in some countries such as Finland and Japan the incidence rate is slightly higher.
Genetic predisposition
The disease is caused by mutations in the SLC7A7 gene, which codes for transport proteins responsible for the removal of amino acids from cells. Dysfunction of these proteins through mutation leads to the accumulation of amino acids in the cell and subsequent loss from the body in the urine.
Risk factors
Due to the genetic nature of the disease, the main and only risk factor is the presence of a mutation in the SLC7A7 gene in both parents, which is then passed on to the child in an autosomal recessive manner.
Diagnosis of the disease
The main symptoms of the disease are growth retardation and mental retardation, but they are often non-specific and can be observed in other diseases, which complicates diagnosis. The diagnostic criterion is a high content of lysine, arginine and ornithine in the urine. Genetic tests for mutations in the SLC7A7 gene are also used.
Treatment
Currently, there is no correction for the gene changes that cause the disease, so treatment is limited to a diet low in lysine and arginine, but high in ornithine.
List of medicines
There is no direct medicinal effect on the cause of the disease. Vitamins and mineral supplements can be used to correct symptoms.
Disease monitoring
Monitoring of the patient's condition, determination of amino acid levels in the blood and urine, and assessment of psychomotor development are used.
Age-related features of the disease
The disease can be detected in early childhood by characteristic symptoms - growth retardation and mental retardation. However, in the absence of timely diagnosis, the disease can manifest itself at a later age.
Questions and Answers
- What is lysinuric protein intolerance?
Answer: This is a rare inherited metabolic disease in which a mutation in the SLC7A7 gene disrupts the transport of the amino acids lysine, arginine and ornithine from the cell.
- How is this disease diagnosed?
- Can this disease be cured?
Answer: Based on urine analysis, which reveals high levels of the indicated amino acids, as well as genetic tests.
Answer: There is currently no drug treatment, but the symptoms can be reduced through a diet with limited lysine and arginine.
Advice from Dr. Oleg Korzhikov
If your child has high levels of lysine, arginine, and ornithine, or unexplained symptoms of growth and developmental delays, be sure to consult a doctor and immediately undergo testing for a genetic disorder. Do not forget to exclude unnecessary foods high in lysine and arginine from the diet.
Early diagnosis and attention to nutrition will help ensure a better life and development for your child.
