Deficiency of adenosine deaminase 2; special focus on central nervous system imaging

To increase the knowledge of central nervous system (CNS) imaging features in deficiency of adenosine deaminase 2 (DADA2) by examining magnetic resonance imaging (MRI) studies of a relatively large number of patients.

We retrospectively examined neuroimages of 12 patients (7 male, 5 female) diagnosed with DADA2. The mean age of the patients at the time of initial brain MRI was 16.7±10.2 years. Seven patients (58.3%) fulfilled the classification criteria of polyarteritis nodosa. Brain MRI studies were assessed with respect to findings of ischemia, intracranial hemorrhages, focal parenchymal signal abnormalities, cerebral/cerebellar volume loss, and abnormal contrast enhancement. Angiographic studies of 7 patients were evaluated for the signs of vasculitis.

The most frequent finding was acute and/or chronic lacunar ischemic lesions in the brainstem and/or deep gray matter (n=9, 75%). Six patients (50%) revealed MRI findings compatible with recurrent ischemic attacks. Small nodular contrast enhancement (n=2, 16.6%), acute putaminal hemorrhage (n=1, 8.3%) and findings compatible with posterior reversible encephalopathy syndrome (n=1, 8.3%) were also detected. Slight-to-moderate diffuse cerebral and/or cerebellar volume loss (n=7, 58.3%), decreased T1 signal of the bone marrow (n=6, 50%) and optic atrophy (n=1, 8.3%) were the other findings on brain MRI. The only abnormal angiographic finding was reduced caliber of the right distal posterior cerebral artery in MRA of a patient (14.6%).

DADA2 should be included in the differential diagnosis of young patients presenting with ischemic and/or hemorrhagic lesions located in the brainstem and deep gray matter, especially if they have a family history or additional systemic abnormalities.