Hemophagocytic Lymphohistiocytosis: A Rare Complication of an Ultrarare Lysosomal Storage Disease.

Hemophagocytic lymphohistiocytosis (HLH) is a rare and life-threatening hyperinflammatory condition that may be triggered by infections, autoimmune and immunologic disorders, malignancies, and metabolic diseases. Early and accurate diagnosis of HLH and its underlying cause is of paramount importance for proper management and prognosis. We report the case of a Tunisian 21-month-old girl who initially presented clinical features of HLH related to a lysosomal acid lipase deficiency. The genetic sequence analysis of the LIPA gene revealed a never described homozygous mutation c.966G>C (p.Gln322His). The parents were heterozygous for this mutation. Enzyme replacement therapy was not provided for the patient. She received etoposide, corticosteroids, and cyclosporine for the HLH. She is waiting for hematopoietic stem cell transplantation. To the best of our knowledge, this is the second Tunisian case of secondary HLH complicating lysosomal acid lipase deficiency related to a new homozygous mutation: c.966G>C (p.Gln322His).