Human inborn errors of thymic T cell tolerance underlie the production of autoantibodies (auto-Abs) neutralizing type I IFNs, which predispose to severe viral diseases. We analyze 131 female patients with X-linked dominant incontinentia pigmenti (IP), heterozygous for loss-of-function (LOF) NEMO variants, from 99 kindreds in 10 countries. Forty-seven of these patients (36%) have auto-Abs neutralizing IFN-α and/or IFN-ω, a proportion 23 times higher than that for age-matched female controls. This proportion remains stable from the age of 6 years onward. On imaging, female patients with IP have a small, abnormally structured thymus. Auto-Abs against type I IFNs confer a predisposition to life-threatening viral diseases. By contrast, patients with IP lacking auto-Abs against type I IFNs are at no particular risk of viral disease. These results suggest that IP accelerates thymic involution, thereby underlying the production of auto-Abs neutralizing type I IFNs in at least a third of female patients with IP, predisposing them to life-threatening viral diseases.

Linear vesicles or papules in a newborn can be a presenting sign of incontinentia pigmenti (IP). In this report, we present two cases of neonates with cutaneous manifestations of incontinentia pigmenti. In one case, mild peripheral eosinophilia was noted. No extra-cutaneous manifestations were noted otherwise in both cases after complete ophthalmological and neurological evaluations. These cases serve as a reminder for clinicians to consider IP in newborns presenting with linear vesicles or papules.

Discoid lupus erythematosus (DLE), a subtype of chronic cutaneous lupus may be observed in a linear pattern. A 21-year-old woman with history of chronic granulomatous disease state presented to our clinic for a chronic six-year skin eruption on her left eyebrow, left cheek, and left forehead. A punch biopsy of involved left forehead skin was performed and revealed perivascular and periadnexal lymphohistiocytic infiltrate without features of morphea or panniculitis, confirming the histopathologic changes of cutaneous lupus erythematous. The patient was diagnosed with linear DLE, mimicking en coup de sabre, within Blaschko lines. The pathogenesis for DLE in association with chronic granulomatous disease is ambiguous; however, X-linked lyonization is crucial for both conditions and may explain cooccurrence of disease states.

The human IκB Kinase (IKK) is a multisubunit protein complex of two kinases and one scaffolding subunit that controls induction of transcription factor NF-κB activity. IKK behaves as an entity of aberrantly high apparent molecular weight in solution. Recent X-ray crystallographic and cryo-electron microscopy structures of individual catalytic subunits (IKK1/IKKα and IKK2/IKKβ) reveal that they are both stably folded dimeric proteins that engage in extensive homo-oligomerization through unique surfaces that are required for activation of their respective catalytic activities. The NEMO/IKKγ subunit is a predominantly coiled coil protein that is required for activation of IKK through the canonical NF-κB signaling pathway. Here we report size-exclusion chromatography, multi-angle light scattering, analytical centrifugation, and thermal denaturation analyses of full-length human recombinant NEMO as well as deletion and disease-linked variants. We observe that NEMO is predominantly a dimer in solution, although by virtue of its modular coiled coil regions NEMO exhibits complicated solution dynamics involving portions that are mutually antagonistic toward homodimerization. This behavior causes NEMO to behave as a significantly larger sized particle in solution. Analyses of NEMO in complex with IKK2 indicate that NEMO preserves this structurally dynamic character within the multisubuit complex and provides the complex-bound IKK2 further propensity toward homo-oligomerization. These observations provide critical information on the structural plasticity of NEMO subunit dimers which helps clarify its role in diseases and in IKK regulation through oligomerization-dependent phosphorylation of catalytic IKK2 subunit dimers.