Immunodeficiency-101 (varicella zoster virus-specific) (IMD101) is an autosomal dominant immunologic condition characterized by reactivation of varicella zoster virus (VZV) infection in adulthood after primary childhood infection with VZV. The viral reactivation manifests as central nervous system vasculitis with stroke-like episodes and lacunar infarcts on brain imaging. Features include headache, hemiparesis, impaired balance, and other neurologic signs. The disorder results from an impaired innate immune response specifically to VZV DNA. Affected individuals do not have increased susceptibility to other infections. Treatment with acyclovir is effective (Carter-Timofte et al., 2018).