A familial case of Blau syndrome caused by a novel NOD2 genetic mutation

Retinal Vasculitis in Familial Blau Syndrome

INTRODUCTION

Blau syndrome is a rare autosomal dominant condition resulting from mutations in the Nucleotide Oligomerization Domain of 2 ;(NOD2) gene. The disease typically presents in early childhood with a triad of arthritis, dermatitis, and uveitis. In this report, we describe retinal vasculitis as a rare phenotype in a family affected by Blau syndrome.

METHODS

Retrospective case series of 3 family members with Blau Syndrome presenting with bilateral retinal vasculitis. The clinical presentation, systemic features, and imaging findings were reviewed.

RESULTS

Case I, a 3-year-old boy with childhood-onset of arthritis and uveitis. Ocular manifestations were anterior segment inflammation (2  +  cells), keratic precipitates, posterior synechiae, complicated cataract, perivascular choroiditis scars, and diffuse small vascular leakage on fundus fluorescein angiography (FFA). Case II, cousin of Case I, was a 24-years-old female with childhood-onset arthritis and uveitis. Ocular features were bilateral panuveitis and small vessel leakage on FFA. Case III, sibling of case II had late onset of uveitis at 28 years of age. On examination, he had pigment on the anterior lens surface, vitritis, and small vessel vasculitis in both eyes. However, he did not have any history of arthritis or dermatitis. Bilateral small vessel vasculitis was a common feature observed in all the three cases. Case II and III were paternal cousins of Case I. All patients had a pathogenic variant in NOD2 gene (NOD2: g.18773C>T, c.C>T1000, p.R334W) and were diagnosed with familial Blau syndrome.

CONCLUSIONS

We report retinal vasculitis as a rare phenotype of Blau syndrome.

Long-Term Visual Outcome of Patients with Blau Syndrome

PURPOSE

To document the long-term visual outcomes in patients with Blau syndrome.

METHODS

A retrospective institutional cohort study was conducted, and 13 patients with genetically confirmed Blau syndrome were included. Demographic and clinical data were collected from standardised medical charts. Baseline was defined as the first detected uveitis and data were recorded onwards at intervals of 1, 3, 5, 10, 15 and 20 years.

RESULTS

Anterior uveitis was the most common classification at baseline (57.1%). Among patients with documented uveitis lasting 10 years or more, all of them developed panuveitis. Median logMAR visual acuity at baseline was 0 (range -0.5; 0.7), 0.19 (range 0; 1.5) at year 5, and 0.7 (range 0.1 - no perception of light) at year 20, as recorded in 13, 16, and 10 eyes, respectively. All patients received treatment with topical and oral steroids, and multiple systemic immunosuppressants including biologics. Disease control, defined as having cells <1+ in both eyes and using topical steroid eye drops less than twice daily, was achieved in 14.3% to 37.5% of patients at the different time points. Cataract surgery was performed in 12 eyes of 8 patients, 3 eyes of 3 patients necessitated glaucoma surgery, and 4 eyes of 4 patients required surgery for retinal detachment.

CONCLUSION

Uveitis associated with Blau syndrome commonly leads to severe, chronic panuveitis, requiring long-term systemic immunosuppression. Early diagnosis and timely initiation of biologics may prevent significant visual impairment.

Ocular sarcoidosis in adults and children: update on clinical manifestation and diagnosis

Sarcoidosis-associated uveitis, is the predominant ocular sarcoidosis presentation, which affects both adults and children. For adults, international ocular sarcoidosis criteria (IWOS) and sarcoidosis-associated uveitis criteria (SUN) are defined. However, for children they are not yet established internationally. Due to the specificity of pediatric manifestations of sarcoidosis, this task is even more challenging. In children, sarcoidosis is subdivided into Blau syndrome and early-onset sarcoidosis (BS/EOS) affecting younger children (< 5 years) and the one affecting older children with clinical presentation resembling adults. Differential diagnosis, clinical work-up as well as diagnostic criteria should be adapted to each age group. In this article, we review the clinical manifestation of sarcoidosis-associated uveitis in adults and children and the sensitivity and specificity of various ocular sarcoidosis diagnostic modalities, including chest X-ray and CT, FDG PET-CT, gallium-67 scintigraphy, bronchoalveolar lavage fluid, genetic testing for NOD2 mutations and serum biomarkers, such as ACE, lysozyme and IL2R.

Blau syndrome with hypertension and hepatic granulomas: a case report and literature review

Background

Blau syndrome (BS) is a monogenic disorder caused by NOD2 gene variants characterized by the triad of granulomatous polyarthritis, rash, and uveitis. Atypical symptoms were recognized in one-third to one-half of individuals with BS. This study aims to describe the clinical features of BS patients with hypertension and digestive system involvement.

Methods

The complete clinical data of a BS patient complicated with hypertension and hepatic granulomas were collected and documented. We also performed a literature search to find all reported cases of BS with hypertension and digestive system involvement.

Results

We reported the case of a 19-year-old man who presented with early onset symmetric polyarthritis and hypertension at age 5 and hepatic granulomas and cirrhosis at age 19. He was diagnosed with BS by the finding of a variant of the NOD2 gene (R334W). Through the literature review, 24 patients with BS were found who were reported to have hypertension, and 38 patients were found who had different digestive system manifestations such as hepatic granulomas, hepatosplenomegaly, diverticulitis, and intestinal granuloma. Among the 38 BS patients with digestive system involvement, 14 had hepatic granulomas proven by liver biopsy.

Conclusions

Hypertension and digestive system involvement are rare manifestations of BS. Clinicians, especially rheumatologists, must be aware of atypical symptoms of BS.

Common condition with uncommon cause: fungal folliculitis in immunosuppressed patient with Blau syndrome

We present a case of a patient with a history of Blau syndrome, who presented with acute onset of widespread florid painful folliculitis rash, which was resistant to the treatment with multiple courses of antibiotics in the community. Despite of the negative skin swab and negative periodic acid-schiff (PAS)stain on the skin biopsy, clinical diagnosis was fungal folliculitis and patient responded well to the course of itraconazole.

Blau Syndrome Complicated by Atypical Type IIa Takayasu Arteritis

Blau syndrome (BS) is a rare, autosomal dominant monogenic autoinflammatory disease, usually presenting as a triad of symptoms (granulomatous dermatitis, uveitis, and nonerosive arthritis) and caused by gain-of-function mutations in the nucleotide oligomerization domain 2 (NOD2) gene. However, very few reports in children of copresence of BS with large vessel vasculitis exist. We hereby describe a case of BS associated with clinical features of Takayasu arteritis. An 8.5-year-old boy presented with hypertension, cardiac insufficiency, arthritis, and ocular disease. Among other investigations, he underwent cervical and chest computed tomography and computed tomography angiography scans that revealed the presence of type IIa Takayasu arteritis lesions. Genetic analysis revealed a heterozygous mutation of NOD2 gene leading to the amino acid exchange Arg-587-Cys in the NACHT domain of the NOD2 protein (R587C) as pathogenic cause of BS. He received treatment with prednisolone, methotrexate, and infliximab (antitumor necrosis factor-α) in addition to antihypertensive medication with a favorable clinical response. Cases of BS should be investigated for the coexistence of Takayasu arteritis. However, further research is required to delineate a possible common pathogenic mechanism between the two clinical entities.

Ocular involvement in monogenic autoinflammatory disease

OBJECTIVE

Monogenic Autoinflammatory diseases (AIDs) are a broad spectrum of rare hereditary diseases whose ocular involvement has not been well characterized yet. This systematic review aims to provide an overview of the current knowledge about ocular findings in AIDs.

METHODS

A systematic literature review was conducted using 2 electronic databases, according to the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines. A combination of AIDs and ophthalmology-related search terms were used. All articles were screened by 2 independent reviewers for title, abstract and full text level. We included solely studies that investigated ocular findings in AIDs.

RESULTS

198 papers of 4268 records were retained. Data about 1353 patients with a diagnosis of autoinflammatory disease and ocular involvement were collected (680 CAPS, 211 FMF, 138 TRAPS, 238 Blau, 32 MKD, 21 SIFD, 7 Aicardi Goutières, 3 CANDLE, 8 DADA2, 9 HA20, 6 APLAID). Conjunctivitis was significantly more frequent in CAPS (p < 0.00001), uveitis in Blau, MKD, HA20 and CANDLE (p < 0.00001), papillitis/papilledema in CAPS (p < 0.00001), optic neuritis in Aicardi and DADA2 (p < 0.008), retinal vasculitis in FMF (p < 0.00001), progressive reduction in choroidal thickness in FMF and DADA2 (p < 0.00001), periorbital oedema in TRAPS (p < 0.00001) and retinitis in SIFD (p < 0.00001). Among AIDs with uveitis, granulomatous inflammation was more common in Blau syndrome (p < 0.00001).

CONCLUSION

This systematic literature review characterized the ocular involvement of several AIDs, and the present data may encourage to consider a timely ophthalmological screening program for these rare diseases.

NF-κB: At the Borders of Autoimmunity and Inflammation

The transcription factor NF-κB regulates multiple aspects of innate and adaptive immune functions and serves as a pivotal mediator of inflammatory response. In the first part of this review, we discuss the NF-κB inducers, signaling pathways, and regulators involved in immune homeostasis as well as detail the importance of post-translational regulation by ubiquitination in NF-κB function. We also indicate the stages of central and peripheral tolerance where NF-κB plays a fundamental role. With respect to central tolerance, we detail how NF-κB regulates medullary thymic epithelial cell (mTEC) development, homeostasis, and function. Moreover, we elaborate on its role in the migration of double-positive (DP) thymocytes from the thymic cortex to the medulla. With respect to peripheral tolerance, we outline how NF-κB contributes to the inactivation and destruction of autoreactive T and B lymphocytes as well as the differentiation of CD4⁺-T cell subsets that are implicated in immune tolerance. In the latter half of the review, we describe the contribution of NF-κB to the pathogenesis of autoimmunity and autoinflammation. The recent discovery of mutations involving components of the pathway has both deepened our understanding of autoimmune disease and informed new therapeutic approaches to treat these illnesses.

NOD1 and NOD2 in inflammatory and infectious diseases

It has been long recognized that NOD1 and NOD2 are critical players in the host immune response, primarily by their sensing bacterial peptidoglycan-conserved motifs. Significant advances have been made from efforts that characterize their upstream activators, assembly of signaling complexes, and activation of downstream signaling pathways. Disruption in NOD1 and NOD2 signaling has also been associated with impaired host defense and resistance to the development of inflammatory diseases. In this review, we will describe how NOD1 and NOD2 sense microbes and cellular stress to regulate host responses that can affect disease pathogenesis and outcomes.

Novel NOD2 Mutation in Early-Onset Inflammatory Bowel Phenotype

BACKGROUND

Nucleotide-binding oligomerization domain 2 (NOD2) is a key intracellular protein of the innate immune system. NOD2 variants are associated with inflammatory bowel disease (IBD) and other inflammatory phenotypes. We described the case of a baby with a very early-onset IBD who is characterized by a rare homozygous variant in NOD2, found through whole-exome sequencing, Its pathogenic effect was investigated through bioinformatics and functional studies.

METHODS

The microbicide activity of the patient's phagocytes was analyzed using Escherichia coli. HEK293 and Caco2 cell lines were transfected with wild-type and mutated NOD2 cDNA to evaluate the NF-kB activity and the protein distribution. The functionality of the NOD2 pathway was assessed through analysis of the expression of tumor nectrosis factor alpha (TNFα) on monocytes. The levels of various cytokines were quantified in the patient plasma by a multiplex suspension array.

RESULTS

A missense NOD2 mutation, c.G1277A; p.R426H in homozygosis, was found. The patient's microbicide activity was comparable to that observed in controls. HEK293 cells transfected with the mutated cDNA showed a 20-fold increase of NF-kB activation in basal condition. Moreover, Caco2 immunostaining revealed a different cytoplasmic distribution of the mutated protein compared with wild-type. A higher production of TNFα by monocytes and elevated levels of plasmatic cytokines and chemokines were evidenced in the patient.

CONCLUSIONS

This homozygous mutation is functionally relevant and shows a different NOD2 involvement in the IBD phenotype. In our patient, this mutation caused a gain of function typical of the Blau syndrome phenotype, manifesting, however, an IBD-like phenotype.