Evaluation of childhood malignancies presenting with musculoskeletal manifestations from two different divisions: a multicenter study.

BACKGROUND: The aim of the study was to evaluate the approaches of pediatric rheumatologists and pediatric hematologists to patients with similar musculoskeletal (MSK) complaints and to highlight the differences that general pediatricians should consider when referring patients to these specialties. METHODS: This is a cross-sectional study involving the patients who applied to pediatric rheumatology centers with MSK complaints and were diagnosed with malignancy, as well as patients who were followed up in pediatric hematology centers with a malignancy diagnosis, and had MSK complaints at the time of admission. RESULTS: A total of 142 patients were enrolled in the study. Of these patients, 83 (58.4%) applied to pediatric rheumatology centers, and 59 (41.6%) applied to pediatric hematology centers. Acute lymphoblastic leukemia (ALL) was the most common diagnosis among the patients who applied to both centers, with 80 cases (56.3%). The median age of diagnosis was 87 (interquartile range, IQR: 48-140) months. The most common preliminary diagnosis in pediatric rheumatology centers was juvenile idiopathic arthritis (JIA), with 37 cases (44.5%). MSK involvement was mainly seen as arthralgia, and bone pain. While arthralgia (92.7%) was the most common complaint in rheumatology centers, bone pain (88.1%) was more common in hematology centers. The most frequently involved joints were the knee (62.9%), ankle (25.9%), hip (25%), and wrist (14%). The most common laboratory abnormalities were high lactate dehydrogenase (LDH), high C-reactive protein (CRP), anemia, and high erythrocyte sedimentation rate (ESR). Thrombocytopenia, neutropenia, and high LDH were statistically significantly more frequent in patients admitted to hematology centers than in patients admitted to rheumatology centers (p < 0.001, p=0.014, p=0.028, respectively). Patients who applied to rheumatology clinics were found to have statistically significantly higher CRP levels (p=0.032). CONCLUSIONS: Malignancies may present with only MSK system complaints in childhood. Therefore, malignancies should be included in the differential diagnosis of patients presenting with MSK complaints.

A clinical overview of paediatric sarcoidosis: Multicentre experience from Turkey.

OBJECTIVES: We aimed to outline the demographic data, clinical spectrum, and treatment approach of sarcoidosis in a large group of patients and sought to figure out the variations of early-onset (EOS) and late-onset paediatric sarcoidosis (LOS). METHODS: The study followed a retrospective-descriptive design, with the analysis of medical records of cases diagnosed as paediatric sarcoidosis. RESULTS: Fifty-two patients were included in the study. The median age at disease onset and follow-up duration were 83 (28.2-119) and 24 (6-48) months, respectively. Ten (19.2%) cases had EOS (before 5th birthday) and 42 (80.7%) cases had LOS. The most common clinical findings at the time of the disease onset were ocular symptoms (40.4%) followed by joint manifestation (25%), dermatological symptoms (13.5%), and features related to multi-organ involvement (11.5%). Anterior uveitis was the most common (55%) one among ocular manifestations. Patients with EOS displayed joint, eye, and dermatological findings more commonly than patients with LOS. The recurrence rate of disease in patients with EOS (5.7%) and LOS (21.1%) were not statistically different (P = .7). CONCLUSIONS: Patients with EOS and LOS may present with variable clinical features and studies addressing paediatric sarcoidosis cases in collaboration between disciplines will enhance the awareness of this rare disease among physicians and assist early diagnosis with lesser complications.

Inflammatory comorbidities in the largest pediatric Familial Mediterranean fever cohort: a multicenter retrospective study of Pediatric Rheumatology Academy (PeRA)-Research Group (RG).

AIM: The aim of this study was to investigate the frequency and type of FMF-associated inflammatory diseases in a large FMF pediatric patients and to compare them to those FMF patients without concomitant inflammatory diseases. MATERIALS AND METHODS: Familial Mediterranean fever patients enrolled in the Pediatric Rheumatology Academy (PeRA)-Research Group (RG) were included. The patients were divided into two groups according to concomitant inflammatory disease as FMF patients who had a concomitant inflammatory disease (group 1) and FMF patients who did not have a concomitant inflammatory disease (group 1). The clinical findings and treatments were compared between the two groups. RESULTS: The study group comprised 3475 patients with FMF. There were 294 patients (8.5%) in group 1 and 3181 patients (91.5%) in group 2. Juvenile idiopathic arthritis (n = 136) was the most common accompanying inflammatory disease. Arthritis, M694V homozygosity, and the need for biological therapy were more frequently observed in Group 1 (p < 0.05). Fever and abdominal pain were more frequently detected in Group 2 (p < 0.05). FMF patients with concomitant inflammatory diseas more frequently demonstrated colchicine resistance. There were no significant differences in the median attack frequency, chest pain, amyloidosis, erysipelas-like erythema, or family history of FMF between the two patient groups. CONCLUSION: To the best of our knowledge, this is the largest pediatric cohort reviewed to date. FMF patients may have different clinical profiles and colchicine responses if they have with concomitant inflammatory diseases. Key points • FMF is associated with some inflammatory comorbidities diseases. • To the best of our knowledge, this is the largest cohort evlauated pediatric FMF associated inflammatory comorbidities diseases reviewed to date.

A pediatric case of Takayasu's arteritis with anti-neutrophil cytoplasmic antibody-associated vasculitis triggered by COVID-19 infection.

Takayasu's arteritis (TA) is a rare chronic granulomatous vasculitis characterized by large-vessel involvement. The aorta and its main branches are most commonly involved. Although pulmonary artery involvement is common, hemoptysis or respiratory findings are rarely seen. Herein, we present a case of TA who developed anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis with diffuse alveolar hemorrhage after coronavirus disease 2019 (COVID-19) infection. A 17-year-old female patient with the diagnosis of TA presented with cough, bloody vomiting, and diarrhea. In follow-up, she developed tachypnea and dyspnea and was transferred to the pediatric intensive care unit. The findings on the chest computed tomography were compatible with acute COVID-19 infection, but the SARS-CoV2 reverse transcription-polymerase chain reaction test was negative, but SARS-CoV2 immunoglobulin (Ig) G and IgM antibody tests were positive. The patient was not vaccinated against COVID-19. The bronchoscopy showed bronchial mucosal fragility, bleeding foci, and mucosal bleeding. The broncoalveolar lavage hemosiderin-laden macrophages were seen in the histopathologic examination. The indirect immunofluorescence assay-ANCA test became 3 (+) with myeloperoxidase (MPO)-ANCA of 125 RU/ml (normal: <20). Cyclophosphamide and pulse steroid treatment were started. After immunosuppressive therapy, the patient condition improved and did not have hemoptysis again. The successful response was obtained by applying balloon angioplasty to the patient with bilateral renal artery stenosis. Types of post-COVID vasculitis include thromboembolic events, cutaneous vasculitis, Kawasaki-like vasculitis, myopericarditis, and ANCA-associated vasculitis. It is thought that COVID-19 may impair immune tolerance and trigger autoimmunity with cross-reaction. To the best of our knowledge, the third pediatric case was reported with MPO-ANCA-positive COVID-associated ANCA vasculitis.

Should children with psoriasis be consulted to a rheumatologist? Result from pediatric rheumatology-dermatology collaboration.

OBJECTIVE: The objectives of this study were to determine the musculoskeletal (MSK) conditions associated with pediatric psoriasis (Pso) and to evaluate the thickness of Achilles tendon of children with Pso and healthy controls (HCs). METHODS: Pso patients who were followed-up in dermatology outpatient clinic were referred to a pediatric rheumatology center. All patients and healthy peers were evaluated with standardized forms. Both patients and controls underwent ultrasonographic evaluation for Achilles tendon thickness. RESULTS: A total of 55 pediatric Pso and 46 healthy children were included in the study. Of patients with Pso 56.4% had arthralgia, 25.5% had lower back pain, 18.2% had heel pain, 12.7% had hip pain, and 10.9% described morning stiffness. Arthritis was detected in 7.3%, sacroiliac tenderness in 12.7%, and enthesitis in 9.1% of the patients. Arthralgia, lower back pain, and heel pain were significantly frequent in Pso group than healthy children median left and right Achilles tendon thicknesses of Pso patients who were significantly greater than that of HCs prevalence of psoriatic arthritis (PsA) among Pso patients was 7.3%. CONCLUSION: Evaluation of a child with Pso regularly for the MSK complaints is critical for the early recognition of PsA. Ultrasonography is a useful technique for screening Pso patients for early detection of enthesopaty.

The assessment of autoinflammatory disease classification criteria (Eurofever/PRINTO) in a real-life cohort.

OBJECTIVE: The aim of the study was to determine the sensitivity and specificity rates of Eurofever/PRINTO autoinflammatory recurrent fever classification criteria with real-life data in patients with an autoinflammatory disease. METHODS: A total of 119 patients were included in the study. Based on clinical symptoms, they were divided into four subgroups: cryopyrin-associated periodic syndromes (CAPS), TNF receptor-associated periodic syndrome (TRAPS), mevalonate kinase deficiency (MKD), and syndrome of undifferentiated recurrent fever (SURF) using the Eurofever/PRINTO clinical classification criteria. In the last step, the patients were re-evaluated in the light of genetic results and their final diagnosis was reached. RESULTS: A total of 119 patients, including 37 CAPS, 13 TRAPS, 8 MKD, 39 SURF, 14 NLRP12-related autoinflammatory disease (NLRP12-AID), and 8 familial Mediterranean fever (FMF) patients were evaluated in the study. While the sensitivity of the new clinical Eurofever/PRINTO criteria was 48% for CAPS, 77% for TRAPS, 87.5%for MKD, and the specificity of the clinical criteria was 86% for CAPS, 85% for TRAPS, and 60% for MKD. The sensitivity of the new mixed (genetic plus clinical variables) Eurofever/PRINTO criteria was 27% for CAPS, 61% forTRAPS, 85% for MKD, and the specificity of the mixed criteria for each group was 100%. CONCLUSION: We found the sensitivity of the Eurofever/PRINTO classification criteria to be low as genotypic changes between populations cause phenotypic differences. For this reason, we think that patient-based evaluation is correct rather than standard classification criteria in real life. Key-points • In systemic autoinflammatory diseases, common variants in the populations may alter the phenotype, and making it difficult to classify some patients with the current classification criteria. • In populations with common genetic variants, the classification criteria should be modified according to the clinical phenotype.

Does having MEFV gene sequence variants affect the clinical course and colchicine response in children with PFAPA syndrome?

The primary aim of this study was to document the treatment modalities used in periodic fever, aphthous stomatitis, pharyngitis, and adenitis (PFAPA) syndrome and look for the efficacy and safety of colchicine in the treatment of PFAPA patients. The secondary aim was to search for whether having MEFV (Mediterranean fever) gene sequence variants affect the clinical course and response to colchicine. The study was conducted in 2 pediatric rheumatology centers. The patients that have been diagnosed with PFAPA syndrome between December 2017 and December 2021 were evaluated retrospectively. The study included 157 patients with PFAPA syndrome (54.8% boys and 45.2% girls). The median follow-up duration was 18 (IQR: 12-30) months. One hundred and fifty-five patients (98.7%) had exudative pharyngitis, 120 patients (76.4%) had aphthous stomatitis, and 82 patients (52.2%) had cervical lymphadenitis during the attacks. Clinical features during attacks were not affected by the presence or absence of the MEFV gene sequence variants. Corticosteroid treatment during attacks was given to 152 patients (96.8%). The frequency of fever attacks did not change in 57 patients (37.5%), increased in 57 patients (37.5%), and decreased in 38 patients (25%) after corticosteroid use. Colchicine was given to 122 patients (77.7%) in the cohort. After colchicine treatment, complete/near-complete resolution of the attacks was observed in 57 patients (46.7%). Colchicine led to partial resolution of the attacks in 59 patients (48.4%). In only 6 patients (4.9%), no change was observed in the nature of the attacks with colchicine treatment. The median duration of the attacks was 4 (IQR: 4-5) days before colchicine treatment, and it was 2 (IQR: 1-2.5) days after colchicine treatment. Also, a significant decrease in the frequency of the attacks was observed before and after colchicine treatment [every 4 (IQR: 3-4) weeks versus every 10 (IQR: 8-24) weeks, respectively, (p < 0.001)]. The overall response to colchicine was not affected by MEFV sequence variants. It was seen that the frequency of fever attacks decreased dramatically in both groups, and children with MEFV variants had significantly less attacks than children without MEFV variants after colchicine treatment (every 11 weeks vs every 9.5 weeks, respectively, p: 0.02). CONCLUSION: Colchicine seems to be an effective and safe treatment modality in PFAPA treatment. It led to a change in the nature of the attacks either in the frequency, duration, or severity of the attacks in 95.1% of the patients. This study has shown that having MEFV gene sequence variants did not affect the clinical course or response to colchicine. We recommend that colchicine should be considered in all PFAPA patients to see the response of the patient, irrespective of the MEFV gene mutations. WHAT IS KNOWN: • Periodic fever, aphthous stomatitis, pharyngitis, and adenitis (PFAPA) syndrome is the most common periodic fever syndrome in the world. Familial Mediterranean fever (FMF) is the most common cause of periodic fever syndrome in Turkey. • Colchicine has become a new treatment option in PFAPA. WHAT IS NEW: • Some PFAPA patients have Mediterranean fever (MEFV) gene variants, and it is speculated that PFAPA patients with MEFV gene mutations respond better to colchicine. • The aim of this study was to look for this hypothesis. We have seen that the clinical phenotype and colchicine response of PFAPA patients were not affected by MEFV gene sequence variants.

Is it all about age? Clinical characteristics of Kawasaki disease in the extremely young: PeRA research group experience.

OBJECTIVES: In the evaluation of children with Kawasaki disease (KD), the age of onset is important and complications may occur if the distinctive features are not assessed accordingly. The objective of the study is to define the clinical and laboratory presentations and treatment outcomes of KD in infants ≤6 months of age compared to those >6 months multicentrically. METHODS: This retrospective study reviewed the medical records of the patients diagnosed with KD and followed up between January 2009 and January 2019. RESULTS: A total of 204 KD patients were enrolled and grouped according to age as Group I (≤6 months, n = 31) and Group II (>6 months, n = 173). Except for cervical adenopathy (19.3% vs. 47.4%, p = 0.03), the major clinical manifestations of KD were similar between groups I and II. However, the frequency of incomplete and atypical KD was higher in Group I (38.7% vs. 24.8%, p = 0.04, 38.7% vs. 8.1% p < 0.001, respectively). Clinical features such as vomiting/diarrhea (19.3% vs. 1.1% p < 0.001), aseptic meningitis (19.3% vs. 2.3%, p = 0.001) were more common in Group I. Percentage of neutrophils (45.5 vs. 36, p = 0.004) and hemoglobin levels (8 vs. 10.5 gr/dL, p = 0.02) were statistically lower and platelet count (737,000 vs 400,000/mm3, p = 0.004) was statistically higher in group I. Coronary artery lesions (CALs) were more common in Group I (48% vs. 20%, p < 0.001). Harada and Kobayashi scores appear to be effective in predicting coronary artery lesions (CALs) and IVIG resistance in the entire cohort. There was no diagnostic delay in group I (5.5 vs 6.5 days, p = 0.88). CONCLUSIONS: Since clinical presentations and laboratory features of KD may vary with age, and the frequency of atypical and incomplete presentations is high, awareness of KD in young children should be raised among pediatricians.

Differences and similarities of multisystem inflammatory syndrome in children, Kawasaki disease and macrophage activating syndrome due to systemic juvenile idiopathic arthritis: a comparative study.

To compare the clinical and laboratory findings of multisystem inflammatory syndrome in children (MIS-C), patients with Kawasaki disease (KD) and with macrophage activating syndrome due to systemic juvenile idiopathic arthritis (sJIA-MAS) on real-life data. Patients diagnosed with MIS-C, KD, and sJIA-MAS from 12 different centers in Turkey who were followed for at least 6 months were included in the study. Demographic, clinical, and laboratory findings of all patients were analyzed. A total of 154 MIS-C, 59 KD, and 31 sJIA-MAS patients were included. The median age of patients with MIS-C were higher than those with KD while lower than those with sJIA-MAS (8.2, 3, 12 years, respectively). Myalgia (39.6%), cardiac (50.6%), gastrointestinal (72.7%), and neurological (22.1%) involvements were more common in patients with MIS-C compared to others. MIS-C patients had lower levels of lymphocyte (950 vs 1700 cells/µl) and thrombocyte (173,000 vs 355,000 cells/µl) counts and higher pro-BNP (1108 vs 55 pg/ml) levels than KD. Ferritin levels were higher in patients with MIS-C compared to patients with KD while they were lower than patients with sJIA-MAS (440, 170, 10,442 ng/ml, respectively). Patients with MIS-C had a shorter duration of hospitalization than sJIA-MAS (p = 0.02) while they required intensive care unit admission more frequently (55 vs 8 patients, p < 0.001). The median MAS/sJIA score of MIS-C patients was - 1.64 (- 5.23 to 9.68) and the median MAS/sJIA score of sJIA-MAS patients was -2.81 ([- 3.79] to [- 1.27]). MIS-C patients displayed certain differences in clinical and laboratory features when compared to KD and sJIA-MAS. Definition of the differences and similarities between MIS-C and the other intense inflammatory syndromes of childhood such as KD and MAS will help the clinicians while making timely diagnosis.

Adherence to best practice consensus guidelines for familial Mediterranean fever: a modified Delphi study among paediatric rheumatologists in Turkey.

BACKGROUND: Although not validated fully, recommendations are present for diagnosis, screening and treatment modalities of patients with familial Mediterranean fever (FMF). OBJECTIVE: To review the current practices of clinicians regarding FMF and reveal their adherence to consensus guidelines. METHODS: Fifteen key points selected regarding the diagnosis and management of FMF were assessed by 14 paediatric rheumatologists with a three-round modified Delphi panel. RESULTS: Consensus was reached on the following aspects: genetic analysis should be ordered to all patients when clinical findings support FMF, but its result is not decisive alone. In the absence of clinical features, colchicine should be commenced when two pathogenic alleles and family history of amyloidosis are present. Serum amyloid A testing at each visit is recommended in patients resistant to colchicine, with subclinical inflammation and family history of amyloidosis. Consensus was reached on both the definition of colchicine resistance and starting biologic in resistant cases. Cost, efficiency, ease of use, treatment adherence, accessibility and emergence of adverse events are the factors affecting the choice of biologic agents. In patients without any attack and evidence of subclinical inflammation within the last 6 months following initiation of biologics, treatment dose intervals can be prolonged. CONCLUSION: A consensus was achieved regarding the routine diagnosis and screening and treatment of FMF patients. The definition of colchicine resistance was made and a protocol was created for prolongation of treatment intervals of biologic agents. We anticipate that the results of the study reveal real-life data on the approach to patients in clinical practice.

Neuroimaging of Children With Takayasu Arteritis.

OBJECTIVE: Takayasu arteritis is a rare granulomatous chronic vasculitis that affects the aorta and its main branches. Neurologic manifestations can accompany the disease; however, there is no study on neuroimaging in children with Takayasu arteritis. Therefore, we aimed to evaluate cranial magnetic resonance imaging (MRI) in pediatric Takayasu arteritis patients. MATERIALS AND METHODS: Demographic, clinical, and laboratory data were obtained retrospectively. RESULTS: The study included 15 pediatric Takayasu arteritis patients. All patients presented with constitutional symptoms. Additionally, 6 patients suffered from headache, 2 had syncope, 1 had loss of consciousness, and 1 had convulsion. All patients underwent cranial and diffusion MRI a median 12 months after diagnosis. Cranial MRI findings were normal in 12 patients, whereas 3 patients had abnormal findings, as follows: stenosis in the M1 and M2 segments of the left middle cerebral artery (n = 1); diffuse thinning of the right internal carotid, middle cerebral, and right vertebral and basilar artery (n = 1); as a sequela, areas of focal gliosis in both the lateral ventricular and posterior periventricular regions (n = 1). Among these 3 patients, 1 had no neurologic complaints. CONCLUSION: Abnormal MRI findings can be observed in pediatric Takayasu arteritis patients, even those that are asymptomatic; therefore, clinicians should carefully evaluate neurologic involvement in all pediatric Takayasu arteritis patients.

Real-Life Data From the Largest Pediatric Familial Mediterranean Fever Cohort.

Familial Mediterranean fever (FMF) is the most common monogenic autoinflammatory disease manifesting phenotypic heterogeneity. It is a clinically diagnosed disease supported by MEditerranean FeVer (MEFV) gene mutation analysis. However, the phenotype-genotype correlation is not yet established clearly. We aimed to determine the clinical findings, phenotype-genotype correlation, and treatment outcomes within a large pediatric FMF cohort. The medical charts of children with FMF who were diagnosed and followed up at the eight pediatric rheumatology units were reviewed retrospectively. All patients in the cohort were analyzed for sequence variants in exon 2,3,5 and 10 of the MEFV gene. Patients without any mutations or with polymorphisms including R202Q were excluded. A total of 3,454 children were involved in the study. The mean ± standard deviation of current age, age at symptom onset, and age at diagnosis were 12.1 ± 5.2, 5.1 ± 3.8, and 7.3 ± 4.0 years, respectively. Of 3,454 patients, 88.2% had abdominal pain, 86.7% had fever, 27.7% had arthritis, 20.2% had chest pain, 23% had myalgia, and 13.1% had erysipelas-like erythema. The most common MEFV mutation patterns were homozygous (32.5%) and heterozygous (29.9%) mutations of exon 10. Homozygous M694V was present in 969 patients (28.1%). Allele frequencies of common mutations were M694V (55.3%), M680I (11.3%), V726A (7.6%), and E148Q (7.2%). Children carrying homozygous or compound heterozygous exon 10 mutations had an earlier age of disease onset (4.6 vs. 5.6 years, p = 0.000) and a higher number of attacks per year (11.1 vs. 9.6, p = 0.001). Although 8% of the patients had a family history of amyloidosis, 0.3% (n = 11) had the presence of amyloidosis. M694V homozygosity was detected in nine patients who developed amyloidosis. Colchicine resistance was present in 4.2% of our patients. In this largest pediatric cohort reviewed and presented to date, patients with exon 10 mutations, particularly the M694V homozygous mutation, have been demonstrated earlier disease onset, annual attack count, and more frequent colchicine-resistant cases. Although E148Q is considered as a polymorphism in some populations, it was identified as a disease-causing mutation in our cohort. Secondary amyloidosis is still happening in adults however, it is extremely rare among children, presumably due to increased awareness, tight control, and the availability of anti-IL1 agents in colchicine-resistant cases.

The influence of carrying MEFV gene variants on juvenile systemic lupus erythematosus.

Juvenile-onset systemic lupus erythematosus (jSLE) patients typically have a more severe disease course than adults with SLE. We aimed to assess the prevalence and disease course of jSLE patients carrying MEFV variants. MEFV variant analyses were performed in 44 jSLE patients and effect of these variants on disease severity and course was analyzed by SLEDAI score and SLICC/ACR index. Ten of the patients (22.7%) had a MEFV variant. The median (min-max) SLEDAI score and SLICC/ACR index were 2(0-13) and 0(0-3), respectively. Median age at disease onset, disease duration, SLICC/ACR indexes, SLEDAI scores, clinical and laboratory findings of the patients were comparable in carriers of variants and non-carriers. Nineteen patients (43.2%) had biopsy-proven lupus nephritis and four of these patients had MEFV variants. There was no significant difference between patients with and without MEFV carriers in terms of lupus nephritis. Even though not significant statistically, renal involvement was milder in MEFV carriers than non-carriers. The presence of MEFV variants does not increase the overall susceptibility to jSLE in our cohort, while larger number of patients is required to display the protective role of MEFV variants in jSLE.

Differential diagnosis portfolio of a pediatric rheumatologist: eight cases, eight stories.

There is no single diagnostic test for any rheumatic disease. The diagnosis of a rheumatic disease is made by the sum of the findings in history, physical examination, laboratory, and imaging tests. A differential diagnosis list in pediatric rheumatology is quite long and mainly includes malignant, infectious, and inherited metabolic disorders. We aim to present cases that were referred to a pediatric rheumatology outpatient clinic with provisional diagnosis of a rheumatic disease but finally diagnosed with a non-rheumatic disease in order to emphasize the importance of differential diagnoses. Eight cases were presented in this manuscript. Five cases were referred with the provisional diagnosis of juvenile idiopathic arthritis. Sarcoidosis, chronic non-bacterial osteomyelitis, and autoinflammatory disease were the provisional referral diagnoses in three patients. Definitive diagnoses of the patients were as follows: acute lymphoblastic leukemia (two cases), bilineage acute leukemia, Hodgkin lymphoma, brucellosis, mucolipidosis type III, anhidrotic ectodermal dysplasia, and Freiberg disease. In children presenting with rheumatic complaints malignant, infectious and inherited metabolic disorders should always be in the differential diagnosis list of a pediatric rheumatologist. Alternative diagnoses should always be considered even in patients with a rheumatic disease when the patient does not respond to treatment or follows an unusual clinical course. Key Points • Diagnosis of a rheumatic disease is made by exclusion of all other pathologies. • Malignant and infectious diseases may mimic the signs and symptoms of a rheumatic disease.

Sacroiliitis in children and adolescents with familial Mediterranean fever

Abstract Background: Familial Mediterranean fever (FMF) is an autoinflammatory disease characterized by recurrent episodes of fever and serositis. Sacroiliitis can be observed in some FMF patients. This study aimed to compare the demographic, clinical, and laboratory findings, and treatment in children with FMF and sacroiliitis, and children with juvenile spondyloarthropathy (JSpA). Methods: In total, 1687 pediatric FMF patients that were followed-up between May 2010 and June 2020 were evaluated retrospectively. Among them, those with sacroiliitis ( n = 63) were included in the study and compared to patients with JSpA ( n = 102). Results: The study included 63 FMF patients with sacroiliitis (38 males [60.3%] and 25 females [39.7%]) with a mean age of 15.2 ± 4.1 years. Mean age at symptom onset was 7.2 ± 5.05 years and mean age at diagnosis was 9.74 ± 4.67 years. The most common mutation in the FMF patients was M694V/M694V ( n = 22). Patients were diagnosed with sacroiliitis with a mean of 12 months (range: 6-36 months) after the diagnosis of FMF. Among the FMF patients, 28 (44.4%) had enthesitis, 23 (36.5%) had heel pain, and 11 (17.4%) had low back pain. The study also included 102 JSpA patients (90 males [88.2%] and 12 females [11.8%]). Mean age of patients with JSpA was 16.1 ± 2.8 years. As compared to 102 JSpA patients, patients with FMF and sacroiliitis had higher acute phase reactants, whereas HLA- B27 positivity rate was lower. In addition, axial involvement rate was higher in the JSpA patients. Conclusion: Sacroiliitis is a common co-morbidity in FMF patients. The phenotypic features of these patients are different from patients with JSpA.

ADA2 Deficiency: Case Series of Five Patients with Varying Phenotypes.

OBJECTIVE: To describe the clinical features, genotype, and treatment approaches of patients with confirmed adenosine deaminase 2 (ADA2) deficiency with dissimilar phenotypes. METHODS: A case series of five DADA2 patients from three families was presented. The clinical and laboratory data, treatment protocols, and outcome of the patients were recorded from the patients' medical charts. ADA2 gene was screened by next generation sequencing first and then verified by Sanger sequencing. Serum ADA2 enzyme activity was measured by modified spectrophotometric method. RESULTS: The median (min-max) age at onset of symptoms and age at diagnosis were 11 (9-13.8) years and 15 (9-19) years, respectively. The median (min-max) follow-up period was 8 (6-45) months. There was consanguinity in two families (2/3). The main clinical manifestations are musculoskeletal (5/5), dermatological (4/5), and neurological (2/5). Homozygosity for the p.G47R mutation in ADA2 gene was detected in three patients. A homozygous mutation in ADA2 gene (c.650 T > A; p.Val217Asp) was detected in two siblings. Plasma ADA2 enzymatic activity was absent in all patients. Anti-tumor necrosis factor (TNF) therapy was commenced, and all patients became clinically inactive with normal acute-phase reactants. CONCLUSION: ADA2 mutations should be checked in patients with presence of inflammation and livedoid vasculitis when they have neurological findings, especially in the form of stroke; and a history suggesting for an inherited disease; or presence of resistance to conventional treatment. Besides, anti-TNF seems to be useful for treatment of DADA2.

Diagnostic utility of a targeted next-generation sequencing gene panel in the clinical suspicion of systemic autoinflammatory diseases: a multi-center study.

Systemic autoinflammatory diseases (sAIDs) are a heterogeneous group of disorders, having monogenic inherited forms with overlapping clinical manifestations. More than half of patients do not carry any pathogenic variant in formerly associated disease genes. Here, we report a cross-sectional study on targeted Next-Generation Sequencing (NGS) screening in patients with suspected sAIDs to determine the diagnostic utility of genetic screening. Fifteen autoinflammation/immune-related genes (ADA2-CARD14-IL10RA-LPIN2-MEFV-MVK-NLRC4-NLRP12-NLRP3-NOD2-PLCG2-PSTPIP1-SLC29A3-TMEM173-TNFRSF1A) were used to screen 196 subjects from adult/pediatric clinics, each with an initial clinical suspicion of one or more sAID diagnosis with the exclusion of typical familial Mediterranean fever (FMF) patients. Following the genetic screening, 140 patients (71.4%) were clinically followed-up and re-evaluated. Fifty rare variants in 41 patients (20.9%) were classified as pathogenic or likely pathogenic and 32 of those variants were located on the MEFV gene. We detected pathogenic or likely pathogenic variants compatible with the final diagnoses and inheritance patterns in 14/140 (10%) of patients for the following sAIDs: familial Mediterranean fever (n = 7), deficiency of adenosine deaminase 2 (n = 2), mevalonate kinase deficiency (n = 2), Muckle-Wells syndrome (n = 1), Majeed syndrome (n = 1), and STING-associated vasculopathy with onset in infancy (n = 1). Targeted NGS panels have impact on diagnosing rare monogenic sAIDs for a group of patients. We suggest that MEFV gene screening should be first-tier genetic testing especially in regions with high carrier rates. Clinical utility of multi-gene testing in sAIDs was as low as expected, but extensive genome-wide familial analyses in combination with exome screening would enlighten additional genetic factors causing disease.