Lysinuric protein intolerance (LPI), also called hyperdibasic aminoaciduria, is a rare inborn error of metabolism (IEM) and autosomal recessive disorder of the kidney function pathway. It is caused by a mutation in the SLC7A7 gene which encodes the Y+L amino acid transporter 1 protein, which is involved in the uptake of amino acids, both with sodium for neutral amino acids, and without for dibasic amino acids. In this disorder, the amino acids lysin, arginine and ornithine, found in protein, cannot be broken down, which can cause problems in the systems that use these amino acids, such as the urea cycle. LPI is characterized by a shortage of lysine, arginine and ornithine within the body, causing elevated ammonia levels in the blood. Symptoms of the disorder include failure to thrive after weaning, nausea and vomiting following a meal containing large amounts of protein, as well as osteoporosis, and lung and kidney problems. Treatment with a protein restricted diet is effective, as well as prescription of medication to lower the levels of ammonia in the blood. It is estimated that the LPI affects 1 in 60,000 individuals in certain populations such as in Finland and Japan, and less frequently outside these populations.

Lysinuric Protein Intolerance (LPI) References

Kidney Function References