A Rare Autoimmune Disease Detected in the Differential Diagnosis of Immunodeficiency: Histiocytosis-lymphadenopathy Plus Syndrome.

Mutations in the SLC29A3 gene cause histiocytosis-lymphadenopathy plus (H) syndrome, a rare autosomal recessive genetic condition that affects numerous systems. We present a 7-year-old Syrian patient with pericardial effusion whose acute phase reactants did not decrease despite treatment. In order to emphasize the variety and raise awareness of H syndrome in the hopes of achieving an early diagnosis and appropriate treatment, molecular investigation of SLC29A3-related disorders is crucial. H syndrome is an uncommon genetic condition with a broad spectrum of phenotypes. Therefore, early genetic testing is essential for the accurate diagnosis of patients. Doctors should be aware of this condition and its symptoms and consider autoimmune diseases as a possible alternative diagnosis in patients with suspected immunodeficiency.