Purine nucleoside phosphorylase deficiency is a rare autosomal recessive immunodeficiency disorder characterized mainly by decreased T-cell function. Some patients also have neurologic impairment (review by Aust et al., 1992).

Hyper-IgE syndrome-2 with recurrent infections (HIES2) is an autosomal recessive immunologic disorder characterized by recurrent staphylococcal infections of the skin and respiratory tract, eczema, elevated serum immunoglobulin E, and hypereosinophilia. It is distinguished from autosomal dominant HIES1 (147060) by the lack of connective tissue and skeletal involvement (Renner et al., 2004). For a discussion of genetic heterogeneity of hyper-IgE syndrome, see 147060. See also TYK2 deficiency (611521), a clinically distinct disease entity that includes characteristic features of both autosomal recessive HIES2 and mendelian susceptibility to mycobacterial disease (MSMD; 209950) (Minegishi et al., 2006).

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).