[Lysinuric dibasic protein intolerance: characteristic aspects of bone marrow involvement]

The marrows of patients with lysinuric protein intolerance (LPI) are generally considered as normal, even though autoerythrophagocytosis has been observed in some of them.

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.

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.