Misdiagnosed for 14 Years: Adenosine Deaminase 2 (ADA2) Deficiency in a Teen Mimicking Polyarteritis Nodosa.

The deficiency of adenosine deaminase 2 (DADA2) is an autosomal recessive disorder caused by loss of function mutations in the ADA2 gene (previously the CECR1 gene) on chromosome 22q11. The clinical spectrum of the disease is remarkably broad, and its presentations mimic features of polyarteritis nodosa, such as livedoid rash, hematological abnormalities (e.g., cytopenia), early-onset stroke, hypogammaglobulinemia, and systemic inflammation. Early diagnosis and treatment of DADA2 are crucial, as the clinical features could be potentially life-threatening but treatable. In this study, a 17-year-old male patient is reported with DADA2 whose symptoms mimic those of polyarteritis nodosa. A 17-year-old male patient presented with a 14-year history of abdominal pain, hypertension, and cutaneous lesions initially attributed to polyarteritis nodosa (PAN). He was referred to our center due to ongoing abdominal pain. An abdominal and pelvic computed tomography scan with contrast revealed a retroperitoneal hemorrhage compressing the left kidney. Given his history of abdominal pain, hypertension, hemiparesis, transient ischemic attacks (TIA), anemia, cutaneous lesions, and retroperitoneal hemorrhage, DADA2 was suspected, and a genetic test confirmed the diagnosis. Treatment with anti-TNF (Adalimumab) was initiated, resulting in noticeable improvement. In the follow up, fever, abdominal pain and TIA episodes were subsided and now he has a good clinical condition. Considering DADA2 and conducting a broad screening for other manifestations is recommended for patients presenting with PAN-like symptoms. These patients may become symptomatic later in life, and early diagnosis allows for the consideration of disease-specific treatment options.