Lysinuric protein intolerance with characteristic bone-marrow abnormalities

Background. - The marrows of patients with lysinuric protein intolerance (LPI) are generally considered as normal, even though autoerythrophagocytosis has been observed in some of them. Case reports. - Lysinuric protein intolerance was recognized in two 12 and 15-year-old brothers who had been diagnosed following an immuno-hematological investigation. Clinical history had been characterized by a neonatal macrophage activation syndrome (hepatosplenomegaly, pancytopenia, hypofibrinogenemia and hypertriglyceridemia). A putative diagnosis of familial lymphohistiocytosis had been ruled out because of unusual clinical and immunological course. Both brothers had displayed chronic aversion to high-protein foods, failure to thrive, osteoporosis and developmental delay. Metabolic investigations had revealed chronic hyperammonemia while cationic aminoaciduria (lysine, arginine and ornithine) was only present during L-citrulline supplementation. Bone marrow examinations had been performed during the neonatal period and during later metabolic investigations. They both displayed a peculiar red cell and granulocytes phagocytosis by histiocytes and granulocytes precursors. Conclusions. - This aspect of bone marrow could be considered as a specific sign of LPI. This report suggests that appropriate metabolic investigations should be performed in any unexplained macrophage activation syndrome.