Background: Lysinuric protein intolerance (LPI) is a metabolic disorder resulting from mutations in the SLC7A7 gene that is inherited in the autosomal recessive pattern. The disease has been described sporadically worldwide, including a few cases from Arab countries. The affected patients typically present with failure to thrive, hepatosplenomegaly, and protein intolerance. Various complications such as autoimmune disorders, infiltrative lung disease, hemophagocytic lymphohistiocytosis (HLH), and neurological manifestations could be noted during the disease course.
Methodology: We described patients diagnosed with LPI in Bahrain by reviewing their presentations, complications encountered, genetic variability, and treatment options.
Results: Four patients, two males and two females from three families with an age range between 2 and 14 years, were followed. Failure to thrive and HLH were the main presenting features in all patients. Two novel mutations were detected in the SLC7A7 gene. One of them was a homozygous splice-site mutation of c.1429+1G>C., whereas the second mutation was a homozygous missense mutation of c.168T>G p. (Phe56Leu). Lung complications were found in two patients, autoimmunity observed in two patients, gastrointestinal complication presenting as hemorrhagic gastritis in one patient, and neurological complications were seen in one patient.
Conclusion: The main presenting feature in all the patients was HLH. Two novel mutations in the SLC7A7 gene were detected. Rheumatological complications were variable within the same family members; moreover, hemorrhagic gastritis was reported in one of the patients as a new possible complication related to the disease.
Key words: Lysinuric protein intolerance, hemophagocytic lymphohistiocytosis, pulmonary alveolar proteinosis, osteoporosis, hemorrhagic gastritis
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