DADA2 in a Teenage Boy

A report describes a case of a 17-year-old boy who underwent recurrent neurological symptoms since age 10, beginning with an acute-onset left ulnar axonopathy, that recovered with antitubercular therapy and steroids. 

At 15 years, he experienced a brainstem ischemic stroke, which was later identified with positive anti-nuclear antibodies and negative rest procoagulant/vasculitis. The patient recovered with aspirin and rehabilitation within three weeks. 

A year later, he suffered an acute-onset right foot drop (peroneal axonopathy) that resolved with prednisolone. Ten months thereon, the patient experienced recurrent acute-onset hearing loss that recovered partially with steroids. 

Extensive investigations showed inconclusive results, raising suspicion of an inherited vasculitis syndrome. Whole exome sequencing uncovered a likely pathogenic, homozygous missense variant (c.139G>C, p.Gly47Arg) in exon 2 of the ADA2 gene, establishing the diagnosis of deficiency of adenosine deaminase 2 (DADA2). The patient received weekly etanercept, but aspirin was discontinued because of hemorrhagic stroke risk. The patient remained under constant follow-up for one year without experiencing additional flares.

Chowdhury SR, Kansal B, Maheshwari A. et al. Recurrent Mononeuropathy, Stroke and Deafness in a Teenage Boy. Indian J Pediatr. 2024. https://doi.org/10.1007/s12098-024-05120-2