Lysinuric Protein Intolerance (LPI)

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MedlinePlus Genetics: ⁴² Lysinuric protein intolerance is a disorder caused by the body's inability to digest and use certain protein building blocks (amino acids), namely lysine, arginine, and ornithine. Because the body cannot effectively break down these amino acids, which are found in many protein-rich foods, nausea and vomiting are typically experienced after ingesting protein.People with lysinuric protein intolerance have features associated with protein intolerance, including an enlarged liver and spleen (hepatosplenomegaly), short stature, muscle weakness, impaired immune function, and progressively brittle bones that are prone to fracture (osteoporosis). A lung disorder called pulmonary alveolar proteinosis may also develop. This disorder is characterized by protein deposits in the lungs, which interfere with lung function and can be life-threatening. An accumulation of amino acids in the kidneys can cause end-stage renal disease (ESRD) in which the kidneys become unable to filter fluids and waste products from the body effectively. A lack of certain amino acids can cause elevated levels of ammonia in the blood. If ammonia levels are too high for too long, they can cause coma and intellectual disability.The signs and symptoms of lysinuric protein intolerance typically appear after infants are weaned and receive greater amounts of protein from solid foods.

MalaCards based summary: Lysinuric Protein Intolerance, also known as lpi, is related to orotic aciduria and aminoaciduria, and has symptoms including muscle weakness, vomiting and diarrhea. An important gene associated with Lysinuric Protein Intolerance is SLC7A7 (Solute Carrier Family 7 Member 7), and among its related pathways/superpathways are Transport of inorganic cations/anions and amino acids/oligopeptides and Response to elevated platelet cytosolic Ca2+. Affiliated tissues include breast, bone marrow and lung, and related phenotypes are failure to thrive and intellectual disability

GARD: ¹⁹ Lysinuric protein intolerance (LPI) typically presents after an infant is weaned from breast milk or formula; variable findings include recurrent vomiting and episodes of diarrhea, episodes of stupor and coma after a protein-rich meal, poor feeding, aversion to protein-rich food, failure to thrive, hepatosplenomegaly, and muscular hypotonia. Over time, findings include: poor growth, osteoporosis, involvement of the lungs (progressive interstitial changes, pulmonary alveolar proteinosis) and of the kidneys (progressive glomerular and proximal tubular disease), hematologic abnormalities (normochromic or hypochromic anemia, leukopenia, thrombocytopenia, erythroblastophagocytosis in the bone marrow aspirate), and a clinical presentation resembling the hemophagocytic lymphohistiocytosis/macrophagic activation syndrome. Hypercholesterolemia, hypertriglyceridemia, and acute pancreatitis can also be seen.

UniProtKB/Swiss-Prot: ⁷³ A metabolic disorder characterized by increased renal excretion of cationic amino acid (CAA), reduced CAA absorption from intestine, and orotic aciduria. On a normal diet, LPI patients present poor feeding, vomiting, diarrhea, episodes of hyperammoniaemic coma and growth retardation. Hepatosplenomegaly, osteoporosis and a life-threatening pulmonary involvement (alveolar proteinosis) are also seen. Biochemically LPI is characterized by defective transport of dibasic amino acids at the basolateral membrane of epithelial cells in kidney and intestine.

Disease Ontology: ¹¹ An amino acid metabolic disorder characterized by the body's inability to effectively break down lysine, arginine and ornithine and by renal hyperdiaminoaciduria, especially lysinuria, and by impaired formation of urea with hyperammonemia after protein ingestion. It has material basis in homozygous or compound heterozygous mutation in the amino acid transporter gene SLC7A7 on chromosome 14q11.

OMIM®: ⁵⁷ Lysinuric protein intolerance is caused by defective cationic amino acid (CAA) transport at the basolateral membrane of epithelial cells in kidney and intestine. Metabolic derangement is characterized by increased renal excretion of CAA, reduced CAA absorption from intestine, and orotic aciduria (Borsani et al., 1999). See also dibasic amino aciduria I (222690). (222700) (Updated 08-Dec-2022)

Orphanet: ⁵⁸ Lysinuric protein intolerance (LPI) is a very rare inherited multisystem condition caused by distrubance in amino acid metabolism.

Wikipedia: ⁷⁵ Lysinuric protein intolerance (LPI) is an autosomal recessive metabolic disorder affecting amino acid... more...

Clinical features from OMIM®:

Search Clinical Trials, NIH Clinical Center for Lysinuric Protein Intolerance