| Topic | Key finding | Evidence type | Key publication / DOI |
|---|---|---|---|
| Disease identity | Best-mapped entity is a Mendelian, selective susceptibility to severe VZV disease caused by monoallelic POLR3F deficiency; reported presentation is recurrent VZV CNS vasculitis/meningoencephalitis rather than broad combined immunodeficiency. No confirmed MONDO/OMIM identifier was established from retrieved sources. (pqac-00000013, pqac-00000017) | Human case report + review | Carter-Timofte et al., 2018, *Neurol Neuroimmunol Neuroinflamm*; DOI: https://doi.org/10.1212/NXI.0000000000000500 |
| Causal gene / variant | Causal gene: **POLR3F** (RNA polymerase III subunit F). Reported disease-associated variant: **c.25C>T, p.Arg50Trp (R50W)**, heterozygous; predicted damaging with CADD 25.8; biochemical work suggested preserved expression/solubility, implying functional rather than stability defect. (pqac-00000016, pqac-00000017) | Human genetics + ex vivo functional follow-up | Carter-Timofte et al., 2018; DOI: https://doi.org/10.1212/NXI.0000000000000500 |
| Inheritance | Evidence supports **autosomal dominant / monoallelic susceptibility** with likely **incomplete penetrance**: the variant was present in both affected monozygotic twins and inherited from the father, who reportedly had a prior stroke possibly related to VZV vasculitis. (pqac-00000016, pqac-00000005) | Family segregation + expert review | Carter-Timofte et al., 2018; DOI: https://doi.org/10.1212/NXI.0000000000000500; Carter-Timofte et al., 2018 review; DOI: https://doi.org/10.1016/j.molmed.2018.07.009 |
| Reported patients | Confirmed POLR3F-specific cases in retrieved evidence: **2 monozygotic adult female twins**, both age 37 in review summaries, with recurrent VZV CNS vasculitis due to reactivation. No additional clearly documented POLR3F cases were identified in retrieved 2023–2024 literature. (pqac-00000013, pqac-00000005) | Human case report + review synthesis | Carter-Timofte et al., 2018; DOI: https://doi.org/10.1212/NXI.0000000000000500 |
| Core phenotype | Recurrent stroke-like CNS disease with **headache, dizziness, hemiparesis/sensory deficits**, CSF pleocytosis and intrathecal anti-VZV antibody production, and brain MRI ischemic lesions; one summary also notes myelitis and parietal/juxtacortical lesions. Patients reportedly had normal childhood varicella and no unusual susceptibility to other infections. (pqac-00000013, pqac-00000015, pqac-00000017) | Human clinical phenotype | Carter-Timofte et al., 2018; DOI: https://doi.org/10.1212/NXI.0000000000000500 |
| Diagnostic findings | Supportive findings included **CSF pleocytosis**, **intrathecal VZV IgG production**, VZV CNS vasculitis-compatible MRI ischemic lesions, and normal routine immune workup (normal immunoglobulins, lymphocyte distribution/proliferation, HIV negative). Broader VZV vasculopathy literature emphasizes that CSF anti-VZV IgG is often more sensitive than PCR and that negative PCR does not exclude disease. (pqac-00000013, pqac-00000015, pqac-00000017) | Human case report + disease review | Carter-Timofte et al., 2018; DOI: https://doi.org/10.1212/NXI.0000000000000500; Nagel & Bubak, 2018; DOI: https://doi.org/10.1093/infdis/jiy425 |
| Functional mechanism | POLR3F deficiency impairs **POL III sensing of AT-rich DNA** and downstream **RIG-I/MAVS/type I and III IFN** responses. Patient PBMCs showed reduced antiviral/inflammatory responses to **poly(dA:dT)** and **increased VZV replication/gene expression** versus controls. Reviews place POLR3F with POLR3A/C/E as Pol III subunits involved in human VZV susceptibility. (pqac-00000013, pqac-00000018, pqac-00000001, pqac-00000003, pqac-00000005) | Human ex vivo immunology + mechanistic reviews | Carter-Timofte et al., 2018; DOI: https://doi.org/10.1212/NXI.0000000000000500; Lata et al., 2021; DOI: https://doi.org/10.3389/fmolb.2021.696438 |
| Acute treatment | In the reported family/case summaries, acute episodes were treated with **intravenous acyclovir 10 mg/kg three times daily for 14 days** plus **prednisolone 50 mg daily for 10 days**. Broader VZV vasculopathy reviews support IV acyclovir as standard acute therapy, with corticosteroids used as adjuncts in selected cases. (pqac-00000015, pqac-00000018) | Human case report + clinical review | Carter-Timofte et al., 2018; DOI: https://doi.org/10.1212/NXI.0000000000000500; Nagel & Bubak, 2018; DOI: https://doi.org/10.1093/infdis/jiy425 |
| Prophylaxis | Both twins reportedly received **acyclovir prophylaxis**; one twin had symptom recurrence/new white matter lesions after stopping prophylaxis. Expert review further suggested that individuals with POL III defects may benefit from **childhood varicella vaccination, adult zoster vaccination, and acyclovir prophylaxis after severe/recurrent VZV**, but these are opinion-based rather than trial-proven for POLR3F disease. (pqac-00000013, pqac-00000008) | Human case follow-up + expert opinion | Carter-Timofte et al., 2018; DOI: https://doi.org/10.1212/NXI.0000000000000500; Carter-Timofte et al., 2018 review; DOI: https://doi.org/10.1016/j.molmed.2018.07.009 |
| Epidemiology | **Unknown disease prevalence/incidence.** Retrieved evidence supports only a single affected family (2 confirmed twins). By contrast, the wider Pol III/VZV susceptibility literature includes additional non-POLR3F patients with POLR3A/C/E variants. Thus, POLR3F-related disease appears **ultra-rare**. (pqac-00000005, pqac-00000001, pqac-00000017) | Case-based evidence + review synthesis | Carter-Timofte et al., 2018; DOI: https://doi.org/10.1212/NXI.0000000000000500; Lata et al., 2021; DOI: https://doi.org/10.3389/fmolb.2021.696438 |
| Major evidence gaps | No disease-specific prevalence estimates, natural-history cohort, penetrance study, controlled treatment trial, validated biomarker panel, or disease-specific animal model were identified. It remains unclear which cell types are decisive in vivo, whether POL III acts mainly in cytosolic DNA sensing versus nuclear RNA5SP14-related signaling, and how POLR3F defects influence latency/reactivation control. (pqac-00000008, pqac-00000000, pqac-00000017) | Knowledge-gap synthesis from reviews + case report | Carter-Timofte et al., 2018 review; DOI: https://doi.org/10.1016/j.molmed.2018.07.009; Kennedy et al., 2021; DOI: https://doi.org/10.3390/v13102018 |


*Table: This table summarizes the highest-confidence evidence for Immunodeficiency 101 (VZV-specific), best mapped here to POLR3F-related selective susceptibility to severe VZV CNS disease. It highlights what is known from primary human cases and reviews, while clearly marking major unresolved gaps.*