Incidence of chronic recurrent multifocal osteomyelitis in children and adolescents in the UK and Republic of Ireland.

OBJECTIVES: Chronic Recurrent Multifocal Osteomyelitis (CRMO), also known as chronic nonbacterial osteomyelitis (CNO), is a rare autoinflammatory condition affecting the bones in children and teenagers. The actual incidence of CRMO remains uncertain. The objective of this study is to identify the incidence of CRMO in children and young people under the age of 16 years in the United Kingdom (UK) and Republic of Ireland (ROI). We also aim to delineate the demographics, clinical presentation, investigations, initial management and healthcare needs for children and adolescents with CRMO. METHODS: We conducted monthly surveys among all paediatric consultants and paediatric orthopaedic surgeons to identify patients newly diagnosed with CRMO between October 2020 and November 2022. A standardised questionnaire was sent to reporting clinicians to collect further information. RESULTS: Over the surveillance period, 288 patients were reported, among which, 165 confirmed and 20 probable cases were included in the analysis. The highest incidences were among 8-10 year-olds. A two-to-one female-to-male difference in incidence was observed, and male patients were more likely to present with multifocal disease. A negative correlation was observed between reporting clavicular and leg pain. Investigation-wise, 80.0% of patients were reported to have undergone whole-body MRI and 51.1% had bone biopsies. The most common initial treatments were NSAIDs (93.9%) and bisphosphonates (44.8%). CONCLUSION: This study estimates an average annual CRMO incidence of 0.65 cases per 100 000 children and adolescents in the UK and ROI. These findings establish a crucial baseline for ongoing research and improvement in the care of individuals with CRMO.

HLA-B*27 is associated with CNO in a European cohort.

OBJECTIVES: To determine the influence of HLA-B27 positivity on risk of developing chronic nonbacterial osteomyelitis (CNO). METHODS: HLA-B*27 genotype was assessed in 3 European CNO populations and compared with local control populations (572 cases, 33,256 controls). Regional or whole-body MRI was performed at diagnosis and follow-up in all cases which reduces the risk of disease misclassification. Genotyping was performed using either next generation DNA sequencing or PCR based molecular typing. Statistical analysis used Fisher's exact test with Bonferroni correction and a fixed effects model for meta-analysis of odds ratios. RESULTS: HLA-B*27 frequency was higher in all 3 populations compared with local controls (combined odds ratio (OR) = 2.2, p-value = 3 × 10-11). This association was much stronger in male compared with female cases (OR = 1.99, corrected p-value = 0.015). However, the HLA-B*27 status was not statistically significantly associated with co-occurrence of psoriasis, arthritis or inflammatory bowel disease. CONCLUSION: Carriage of HLA-B*27 is associated with greater risk of developing CNO, particularly in male cases.

Prospective epidemiological study of juvenile-onset systemic lupus erythematosus in the UK and Republic of Ireland.

OBJECTIVES: The primary objective was to define the incidence of JSLE in children <16 years of age in the UK and Republic of Ireland (ROI). The secondary objective was to describe presenting features, classification criteria, initial management and disease damage in newly presenting JSLE patients. METHODS: A prospective JSLE epidemiological study was undertaken between September 2017 and September 2019 with support of the British Paediatric Surveillance Unit and other professional groups involved in diagnosis and management of JSLE patients. Treating consultants reported all cases of JSLE seen. A follow-up study at 1 year examined management and progression of disease and treatment. RESULTS: There were 124 incident cases included in the final analysis. Incidence was estimated using ACR-1997 classification criteria (0.36/100 000), SLICC-2012 classification criteria (0.41/100 000) and clinician expert opinion (0.46/100 000). A high disease burden was seen, with 71.0% of patients requiring ongoing systemic CS treatment at 1 year; 98.2% receiving immunomodulatory treatment; and 20.4% accruing damage in the year following diagnosis (predominantly neuropsychiatric-related), with substantial involvement from multiple speciality teams. CONCLUSIONS: The minimum UK and ROI incidence of JSLE is between 0.36 and 0.46/100 000, depending on the case definition used. Challenges in classification of patients with JSLE are highlighted, but overall this study supports the use of SLICC-2012 classification criteria. The high levels of disease damage and ongoing CS use 1 year after diagnosis is concerning, highlighting the need for further interventions to improve outcomes in JSLE.

Variability in phenotype and response to treatment in chronic nonbacterial osteomyelitis; the Irish experience of a national cohort.

BACKGROUND: Chronic nonbacterial osteomyelitis (CNO) is an autoinflammatory disease affecting bone with considerable phenotypic heterogeneity and variable association with other autoinflammatory conditions. Disease pathogenesis is incompletely understood, and treatment protocols vary between physicians with no clinical treatment guidelines available prior to 2017. Although CNO was previously considered benign, it is now clear that long-term sequelae do occur. The aim of this study is to provide a detailed phenotypic description of children and adolescents with CNO who attended tertiary paediatric rheumatology services in Ireland between September 2017 and September 2019, their disease course, treatment and outcomes. METHODS: This study involved retrospective review of clinical notes, laboratory, radiology and histology results of Irish children and adolescents with CNO who are currently attending tertiary paediatric rheumatology services. The Bristol diagnostic criteria were applied retrospectively; only patients who met these criteria were included. Criteria for remission and partial response were based on the Childhood Arthritis and Rheumatology Research Alliance (CARRA) criteria for treatment failure. RESULTS: Forty-four children and adolescents were recruited. Demographics in terms of age of onset, gender and number of sites were similar to those previously reported. Overall, 18/44 (40.9%) had extraosseous manifestations associated with CNO; 12/44 (27.2%) had cutaneous involvement. All patients received a regular nonsteroidal anti-inflammatory drug (NSAID) after diagnosis with 27/44 (61.4%) requiring at least 1 second-line medication. Second-line agents used in this cohort were bisphosphonates, methotrexate and TNF-blockers. No patients received systemic corticosteroids. CONCLUSION: This national cohort showed a high prevalence of extraosseous involvement and a low response rate to NSAID treatment. This may reflect a more inflammatory phenotype and highlights the need to define different subtypes of CNO.

A Novel RELA Truncating Mutation in a Familial Behçet's Disease-like Mucocutaneous Ulcerative Condition.

OBJECTIVE: Monogenic Behçet's disease (BD)-like conditions are increasingly recognized and to date have been found to predominantly involve loss-of-function variants in TNFAIP3. This study was undertaken to identify genetic and pathobiologic mechanisms associated with a BD-like mucocutaneous ulcerative syndrome and neuromyelitis optica (NMO) occurring in 3 generations of an Irish family (n = 5 cases and 5 familial controls). METHODS: Whole-exome sequencing was used to identify potential pathogenic variants in affected family members and determine segregation between affected and unaffected individuals. Relative v-rel reticuloendotheliosis viral oncogene homolog A (RELA) expression in peripheral blood mononuclear cells was compared by Western blotting. Human epithelial and RelA-/- mouse fibroblast experimental systems were used to determine the molecular impact of the RELA truncation in response to tumor necrosis factor (TNF). NF-κB signaling, transcriptional activation, apoptosis, and cytokine production were compared between wild-type and truncated RELA in experimental systems and patient samples. RESULTS: A heterozygous cytosine deletion at position c.1459 in RELA was detected in affected family members. This mutation resulted in a frameshift p.His487ThrfsTer7, producing a truncated protein disrupting 2 transactivation domains. The truncated RELA protein lacks a full transactivation domain. The RELA protein variants were expressed at equal levels in peripheral mononuclear cells. RelA-/- mouse embryonic fibroblasts (MEFs) expressing recombinant human RELAp.His487ThrfsTer7 were compared to those expressing wild-type RELA; however, there was no difference in RELA nuclear translocation. In RelA-/- MEFs, expression of RELAp.His487ThrfsTer7 resulted in a 1.98-fold higher ratio of cleaved caspase 3 to caspase 3 induced by TNF compared to wild-type RELA (P = 0.036). CONCLUSION: Our data indicate that RELA loss-of-function mutations cause BD-like autoinflammation and NMO via impaired NF-κB signaling and increased apoptosis.

Emerging Role of the NLRP3 Inflammasome and Interleukin-1ß in Neonates.

Infection and persistent inflammation have a prominent role in the pathogenesis of brain injury and cerebral palsy, as well as other conditions associated with prematurity such as bronchopulmonary dysplasia. The NLRP3 inflammasome-interleukin (IL)-1ß pathway has been extensively studied in adults and pre-clinical models, improving our understanding of innate immunity and offering an attractive therapeutic target that is already contributing to clinical management in many auto-inflammatory disorders. IL-1 blockade has transformed the course and outcome of conditions such as chronic infantile neurological, cutaneous, articular (CINCA/NOMID) syndrome. Inflammasome activation and upregulation has recently been implicated in neonatal brain and lung inflammatory disease and may be a novel therapeutic target.

Treatment-recalcitrant laryngeal sarcoidosis responsive to sirolimus.

A 15-year-old girl presented with gradual-onset dysphonia and dysphagia. Laryngoscopy revealed significant supraglottic airway obstruction with swelling of both the epiglottis and arytenoids. After emergency tracheostomy, biopsy of the epiglottis revealed lymphoid hyperplasia with focal non-necrotising granulomata, leading to a presumed diagnosis of laryngeal sarcoidosis. Treatment with prednisolone and methotrexate produced minimal clinical improvement. A switch to sirolimus was followed by significant reduction in the laryngeal swelling, allowing decannulation of the tracheostomy. Treatment with sirolimus should be considered as a steroid sparing agent in laryngeal sarcoidosis, particularly in the presence of lymphoid hyperplasia on biopsy.

Arthropathy of Down syndrome: an under-diagnosed inflammatory joint disease that warrants a name change.

There is an increased incidence and prevalence of arthropathy in children with Down syndrome. However, it is rarely reported or recognised at onset, and remains under-diagnosed. Children with arthropathy of Down syndrome (A-DS) are presenting with significant joint damage and disability at diagnosis. Objective: To identify undiagnosed cases of A-DS and document time to diagnosis. Also to describe clinical, laboratory and radiological features of A-DS at diagnosis. Methodology: Children with Down syndrome (DS) (0-21 years) were invited to attend a musculoskeletal screening clinic. A second physician at a further clinic confirmed suspected cases of A-DS. Investigations and treatment were instigated as per normal clinical practice for Juvenile idiopathic arthritis (JIA). Data on a convenience sample of 21 newly diagnosed children with JIA was collected to create a comparison group. Results: Over an 18-month period, 503 children with DS were screened for arthritis and 18 new cases diagnosed. In total, 33 children were identified with A-DS (combining cases attending pre-dating commencement of the study and those referred to our centre during the study period). This suggests prevalence of A-DS is 20/1000. A significant delay in diagnosis of A-DS was observed. The majority of children presented with polyarticular-rheumatoid factor-negative arthritis, with predominance in the small joints of the hands and wrists. Erosive changes were reported on X-ray in a significantly greater proportion (42%) of children with A-DS than JIA (14%). MRI was used to confirm diagnosis in four cases. Conclusion: Children with DS are at increased risk of arthritis. Future research to accurately define disease pathogenesis and identify a biomarker of disease would be of benefit.

Musculoskeletal anomalies in children with Down syndrome: an observational study.

BACKGROUND: Musculoskeletal complications of Down syndrome (DS) are common but infrequently reported. The combination of ligamentous laxity and low muscle tone contributes to increased risk of a number of musculoskeletal disorders and a delay in acquisition of motor milestones. The primary aim of this study was to describe musculoskeletal anomalies reported in a national cohort of children with DS. METHODS: This was an observational study. Children with DS, aged 0-21 years, were invited to attend a musculoskeletal assessment clinic conducted by a paediatric physician. Relevant musculoskeletal history and clinical findings were documented. RESULTS: Over an 18-month period, 503 children with DS were examined (56% male). The median age was 8.1 years (0.6-19.2). Pes planus was almost universal, occurring in 91% of the cohort. A range of other musculoskeletal anomalies were observed, with inflammatory arthritis (7%) and scoliosis (4.8%) occurring most frequently after pes planus. Delay in ambulation was common; the median age to walk was 28 months (12-84). CONCLUSION: Children with DS are at increased risk of a number of potentially debilitating musculoskeletal problems. These conditions can present in variable manners or be completely asymptomatic. Pes planus is common; therefore, early consideration of orthotics and lifelong appropriate supportive footwear should be considered. Delayed ambulation is frequently noted. A significant proportion of children with DS have arthritis; however, despite a high prevalence, it is often missed, leading to delayed diagnosis. An annual musculoskeletal assessment for all children with DS could potentially enable early detection of problems, allowing for timely multidisciplinary team intervention and better clinical outcomes.

Magnetic resonance imaging identifies features in clinically unaffected knees predicting extension of arthritis in children with monoarthritis.

OBJECTIVE: A proportion of children with oligoarthritis have an aggressive disease course. Identifying these children at presentation would help guide prognosis and management. We examined if magnetic resonance imaging (MRI) of clinically unaffected joints is more sensitive than clinical assessment in identifying those at risk of developing arthritis in more than one joint. METHODS: Ten children were recruited; they had a mean age of 9.4 (range 5.2-14.2) years at presentation of a monoarthritis. MRI of a clinically unaffected knee was performed within 4 months of presentation, and was reported by 2 pediatric radiologists blinded to the clinical findings. All MR examinations included post-gadolinium sequences. Joints with clinically apparent arthritis were recorded regularly over a median of 37.0 (range 6.6-47.0) months by a median of 6.0 (range 2-8) pediatric rheumatologists blinded to the MR result. RESULTS: Four children developed arthritis in other joints over a median of 3.9 (range 3-6) months after the MRI scan; all had abnormal MRI scans at presentation. Three of these developed clinical features in the previously normal knee 4-11 months after MRI identified small joint effusions, synovial hypertrophy, and lymph node enhancement. One child developed a polyarthritis, but never developed clinical features in the imaged knee over 3.8 years of followup. Four other children had a persistent monoarthropathy with a median followup of 29.5 (range 6.6-42.0) months. All 4 had normal MRI. Two children had reactive arthritis. CONCLUSION: MRI distinguished between patients with a persistent monoarthritis and those who developed further clinical arthritis up to 1 year later. The results suggest a widespread inflammatory process may exist in children whose arthritis extends, and this has implications for our understanding of disease and the design and timing of therapeutic interventions.

Double vagina with sex reversal, congenital diaphragmatic hernia, pulmonary and cardiac malformations--another case of Meacham syndrome.

We report a female infant of 42 weeks gestation with a left sided diaphragmatic hernia and a hypoplastic left heart. A true double vagina, absent uterus and abnormal male gonads were found in the presence of normal external female genitalia. Conventional G band karyotyping of skin samples revealed a normal male karyotype. The aetiology and inheritance are unknown. We believe this to be the fifth reported case of a recognizable syndrome first reported by Meacham [(1991). Am J Med Genet 41:478-481].