CBL syndrome presenting with catastrophic EBV infection and severe bilateral pseudo-uveitis.
Purpose
To describe a case of CBL syndrome presenting with life-threatening EBV infection and severe bilateral inflammatory rod-cone dystrophy (RCD) masquerading as panuveitis.
Methods
Case report.
Results
A 3-year-old boy presented with catastrophic EBV-related infectious mononucleosis characterized by severe organomegaly (lymphadenopathy and hepatosplenomegaly), encephalitis and hemophagocytic lymphohistiocytosis. The clinical picture improved following treatment with intravenous corticosteroids. Three years later, at 6 years old, he developed severe bilateral panuveitis for which an extended work-up was negative. He received multiple lines of treatment with immunosuppressive agents (corticosteroids, methotrexate, azathioprine, rituximab, interferon alfa-2a, sirolimus) mainly for control of chronic cystoid macular edema (CME). During follow-up, he developed retinitis pigmentosa-like dystrophic features (symmetric outer retinal atrophy, scotopic more than photopic dysfunction on full-field electroretinogram, peripheral spicular intraretinal pigment migrations). Whole-exome sequencing (WES) analysis performed on nail tissue revealed a constitutional heterozygous missense variant in the CBL gene. Heterozygous germline pathogenic variants in the CBL gene underlie the autosomal dominant CBL syndrome (high risk of developing juvenile myelomonocytic leukemia, susceptibility to severe EBV primary infection, Noonan-like dysmorphic features, inflammatory RCD).
Conclusion
CBL syndrome is an emerging cause of severe inflammatory RCD masquerading as uveitis. Patients often have a history of severe EBV primary infection.