A case of infantile Takayasu arteritis with a p.D382E NOD2 mutation: an unusual phenotype of Blau syndrome/early-onset sarcoidosis?

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.

Effective treatment of TNFα inhibitors in Chinese patients with Blau syndrome

Objectives

Blau syndrome (BS) is a rare dominantly inherited autoinflammatory disorder associated with mutations in the nucleotide-binding oligomerization domain containing 2 (NOD2) gene. Biologic therapy of BS yielded diverse results. We aimed to evaluate clinical features and outcomes of Chinese patients with BS who were treated with tumor necrosis factor (TNF)α inhibitors.

Methods

A total of four patients with BS were diagnosed and treated with infliximab (IFX) at the Peking Union Medical College Hospital during 2015 to 2018 and were followed up for 18 months. All patients were systematically studied for treatment outcomes including the clinical manifestations and inflammatory markers. We also conducted a comprehensive literature review about TNFα inhibitor therapy in BS.

Results

Four BS patients were all Chinese Han, and three were women. The mean age of disease onset was 4 ± 3.5 years, and the mean time of diagnosis delay was 19 ± 11 years. All patients received IFX plus methotrexate, and all achieved clinical remission of skin lesions and polyarthritis rapidly, as well as normalization of erythrocyte sedimentation rate and C-reactive protein and improvements in inflammatory cytokines, patient visual analogue scale, physician global assessment, and Short Form (SF)-36, at the first follow-up of 6 months. The disease relapsed in two patients after they lengthened the interval of IFX and discontinued methotrexate. According to the 38 English-language publications, 62 patients with BS were reported who underwent TNFα inhibitor therapy, including IFX used in 31, adalimumab in 24, and etanercept in 7. IFX was well tolerated in 27 patients, while 2 still had uveitis, and the other 2 experienced an adverse drug reaction.

Conclusions

Early recognition and effective treatment of BS are very important to avoid irreversible organ damage. TNFα inhibitors such as IFX may be a promising approach for BS patients who have unsatisfactory response to corticosteroids and traditional disease-modifying antirheumatic drugs.

Blau Syndrome and Early-Onset Sarcoidosis: A Six Case Series and Review of the Literature

Objectives

This study aims to discuss the clinical, laboratory and genetic findings, and treatment options for six patients who were diagnosed with Blau syndrome (BS)/early-onset sarcoidosis (EOS).

Patients and methods

The study included four patients (2 males,2 females; mean age 7 years; range 4 to 10 years) with EOS and two siblings (1 male, 1 female; mean age 10 years; range, 9 to 11 years) with BS. Age, age of initial symptoms, age of diagnosis; articular involvement, presence of uveitis, dermatitis, or fever, other organ involvement, laboratory findings, results of metabolic tests for mucopolysaccharidosis and mucolipidosis, results of genetic, pathologic, and immunologic tests, radiologic findings to evaluate skeletal dysplasia, and treatment options were collected.

Results

The median age at diagnosis of all patients was 6 years (range, 1 to 10 years). Five patients had camptodactyly and bilateral boggy synovitis in the wrists and ankles, one had granulomatous inflammatory changes in the liver and kidney biopsy, and one had attacks of fever and granulomatous dermatitis. None had uveitis. The detected mutations in nucleotide-binding oligomerization domain containing 2 (NOD2) were P268S (rs2066842), M513T (rs104895473), R702W (rs2066844), V955I (rs5743291), H343Y (rs199858111), and M491L (16:50745293). The treatments of patients included corticosteroids, non-steroid anti-inflammatory drugs, methotrexate, infliximab, adalimumab, anakinra, and canacinumab.

Conclusion

Camptodactyly and boggy synovitis are important signs of BS/EOS. Methotrexate and tumor necrosis factor blockers are more effective in patients with predominantly articular symptoms. In patients 5 and 6 and their mother, we determined a novel M491L mutation in the NOD2 gene. Currently, this work is in progress towards identifying the pathogenesis and treatment options for this disease.

A Case of Sporadic Blau Syndrome with an Uncommon Clinical Course

Background

Sporadic Blau syndrome (SBS), a rare systemic inflammatory disease in children, is associated with NOD2 gene mutations. SBS is often misdiagnosed as juvenile idiopathic arthritis (JIA) because of their similar clinical manifestations. Herein, we present a case of SBS with an uncommon clinical course.

Case Presentation

An 11-year-old girl with recurrent right ankle swelling for 4 years was referred to our hospital. One month before admission, she developed an intermittent high fever. She was diagnosed with systemic-onset JIA on the basis of physical and blood examination results. She was treated with ibuprofen, prednisolone, and methotrexate for 5 years. During this period, her joint lesion showed neither bone destruction nor joint space narrowing on radiography, which are characteristics of JIA. Twelve months after the termination of methotrexate treatment, she presented with bilateral panuveitis. A missense mutation, p.(R587C), was detected in her NOD2 gene, and she was diagnosed with SBS. Then, infliximab treatment was started, and her visual acuity recovered.

Conclusion

SBS may sometimes be misdiagnosed as JIA. A joint lesion without bone destruction might be a key feature to distinguish SBS from JIA. Analysis of the NOD2 gene is recommended in such cases.

Autoinflammatory granulomatous diseases: from Blau syndrome and early-onset sarcoidosis to NOD2-mediated disease and Crohn's disease

The recent identification of genetic mutations leading to dysfunction of inflammatory and apoptotic pathways, has allowed to characterise a group of diseases, recognised as monogenic autoinflammatory syndromes. Among those, Blau syndrome (BS) and early-onset sarcoidosis (EOS) have been identified as familial and sporadic phenotypes of the same non-caseating granulomatous form. Both the diseases are caused by mutations in the CARD15/NOD2 gene, encoding the cytosolic NOD2 protein, one of the key molecules in the regulation of innate immunity. Clinical onset is typically located in the first years of life and phenotype is characterised by simultaneous or less articular, cutaneous and ocular non-caseating granulomatous inflammation, which can be variably associated with a heterogeneous systemic spectrum. The CARD15/NOD2 gene has also been identified as one of the genes linked to susceptibility to Crohn's disease (CD), a common polygenic inflammatory granulomatous bowel disease. The heightened nuclear factor-κB activity, found in the intestinal tissue of patients affected by CD, has probably a genetic cause related to several CARD15/NOD2 polymorphisms. Other substitutions in the CARD15/NOD2 gene have also been found in a recently described disorder, called NOD2-associated autoinflammatory disease, which shares several clinical characteristics with BS and EOS. This review attempts to describe these diseases on the basis of the most recent evidences. We described genetic and clinical aspects, mainly focusing on BS and EOS, the most representative diseases of autoinflammatory granulomatous diseases, with the ultimate purpose to expand their knowledge.

Ultrasonographic assessment reveals detailed distribution of synovial inflammation in Blau syndrome

INTRODUCTION

Arthritis is the most frequent manifestation of Blau syndrome, an autoinflammatory disorder caused by the genetic mutation of NOD2. However, detailed information on arthritis in Blau syndrome on which the therapeutic strategy should be based on is lacking. This multi-center study aimed to accurately characterize the articular manifestation of Blau syndrome and also to demonstrate the utility of musculoskeletal ultrasound in Blau syndrome.

METHODS

Patients who had been diagnosed with Blau syndrome by genetic analysis of NOD2 were recruited. A total of 102 synovial sites in 40 joints were assessed semiquantitatively by ultrasound for gray-scale synovitis and synovial power Doppler (PD) signal.

RESULTS

In total, 10 patients whose age ranged from 10 months to 37 years enrolled in this study. Although only 4 joints (0.8%) were tender on physical examination, 81 joints (16.9%) were clinically swollen. Moreover, 240 (50.0%), and 124 (25.8%) joints showed gray-scale (GS) synovitis and synovial PD signal on ultrasound, respectively. Importantly, GS synovitis was present in 168 out of 399 non-swollen joints, in which 61 also exhibited synovial PD signal. Among 40 joint regions, the ankle, the wrist, and the proximal interphalangeal joints were the most frequently and severely affected joints. Comparisons between different synovial tissues demonstrated a significantly higher proportion of the joints with tenosynovitis as compared with that with intra-articular synovitis (41.5% versus 27.9%, P < 0.0001). In respect of age and treatment, synovial PD signals were minimal in the youngest patient and in the oldest two patients, and were relatively mild in patients receiving treatment with methotrexate plus TNF antagonists. In two patients who underwent the second ultrasound examination, total PD scores markedly decreased after initiating the treatment with a tumor necrosis factor (TNF) antagonist.

CONCLUSIONS

The detailed information on synovial inflammation obtained by ultrasound confirms the dissociation between pain and inflammation and the frequently involved joint regions and synovial tissue in the arthritis of Blau syndrome. Our data also demonstrate that ultrasonography can be a potent tool in monitoring the activity of synovial inflammation and in investigating the pathophysiology of arthritis in this rare but archetypical autoinflammatory condition.