Monogenic disorders as mimics of juvenile idiopathic arthritis

Case Report: Hypomorphic Ligase 4 deficiency - a paradigm of immunodysregulation

DNA Ligase 4 is critical to nonhomologous end joining, necessary for V(D)J recombination in T and B cell development. Ligase 4 deficiency is a rare autosomal recessive disorder caused by hypomorphic mutations in the DNA Ligase 4 gene, that can lead to a wide range of phenotypes. We describe a case of Ligase 4 deficiency causing a type of T-B-NK+ atypical SCID, highlighting the clinical and immunologic manifestations. An eight-year-old female, from São Nicolau Island (Cape Verde), presented at our hospital with a history of recurrent pneumonia and suppurative otitis, multiple skin lesions attributed to fungal and bacterial infections since the age of two, and recurrent diarrhea and growth impairment, beginning at the age of four. The laboratory workup showed almost absent B cells, marked hypogammaglobulinemia, and an impaired response to protein antigens. Flow cytometry revealed normal NK and T cell counts, but with nearly absent naïve T cells and TCR-Va7 expressing T lymphocytes, and reduced proliferative responses to mitogens and antigens. An oligoclonal Vβ repertoire was identified by FACS, and PROMIDISa analysis revealed a skewed TCRa repertoire signature. A 477 PID-related genes NGS panel identified a homozygous R278H mutation in the DNA Ligase 4 gene, previously reported to cause Ligase 4 deficiency. Immunoglobulin replacement and prophylactic therapies were started while waiting for hematopoietic stem cell transplantation. She has experienced fluctuating transaminase levels. The cutaneous biopsy was suggestive of lupus pernio. She has shown recurrent inflammatory signs in her limbs, with documented tenosynovitis on ultrasound. Homozygous R278H in Ligase 4 has been linked to various ranges of manifestations in Ligase 4 deficient patients. In our report, this genotype resulted in T-B-NK+ atypical SCID, that after proper prophylaxis has a predominant autoimmune phenotype.

Asymptomatic intraspinal epidermoid cyst in a 7-year-old male with juvenile idiopathic arthritis identified by an advanced physiotherapist practitioner: a case report

BACKGROUND

Pediatric intraspinal epidermoid cysts are rare with potential to cause life-altering outcomes if not addressed. Reports to date describe symptomatic presentations including loss of bladder or bowel function and motor and sensory losses. This case report identifies the diagnostic challenge of an asymptomatic intraspinal epidermoid cyst in the cauda equina region presenting in a 7-year-old male with juvenile idiopathic arthritis (JIA).

DIAGNOSIS

An advanced physiotherapist practitioner assessed and diagnosed a previously healthy 7-year-old-male of South Asian descent with JIA based on persistent knee joint effusions. Complicating factors delayed the investigation of abnormal functional movement patterns, spinal and hip rigidity and severe restriction of straight leg raise, all atypical for JIA. Further delaying the diagnosis was the lack of subjective complaints including no pain, no reported functional deficits, and no neurologic symptoms. A spinal MRI investigation 10-months from initial appointment identified intraspinal epidermoid cysts occupying the cauda equina region requiring urgent referral to neurosurgery.

DISCUSSION

Clinical characteristics and pattern recognition are essential for diagnosing spinal conditions in pediatric populations. Diagnostic challenges present in this case included co-morbidity (JIA), a severe adverse reaction to treatment, a lack of subjective complaints and a very low prevalence of intraspinal epidermoid cysts.

IMPACT STATEMENTS

Early signs of pediatric asymptomatic intraspinal epidermoid cysts included abnormal functional movement patterns, rigidity of spine, severely limited straight leg raise and hip flexion without pain. Advanced physiotherapist practitioners can be integral to pediatric rheumatology teams considering their basic knowledge in musculoskeletal examination and functional mobility assessment when identifying rare spinal conditions that present within the complex context of rheumatic diseases.

Genome Sequencing in an Individual Presenting with 22q11.2 Deletion Syndrome and Juvenile Idiopathic Arthritis

Juvenile idiopathic arthritis is a heterogeneous group of diseases characterized by arthritis with poorly known causes, including monogenic disorders and multifactorial etiology. 22q11.2 proximal deletion syndrome is a multisystemic disease with over 180 manifestations already described. In this report, the authors describe a patient presenting with a short stature, neurodevelopmental delay, and dysmorphisms, who had an episode of polyarticular arthritis at the age of three years and eight months, resulting in severe joint limitations, and was later diagnosed with 22q11.2 deletion syndrome. Investigation through Whole Genome Sequencing revealed that he had no pathogenic or likely-pathogenic variants in both alleles of the MIF gene or in genes associated with monogenic arthritis (LACC1, LPIN2, MAFB, NFIL3, NOD2, PRG4, PRF1, STX11, TNFAIP3, TRHR, UNC13DI). However, the patient presented 41 risk polymorphisms for juvenile idiopathic arthritis. Thus, in the present case, arthritis seems coincidental to 22q11.2 deletion syndrome, probably caused by a multifactorial etiology. The association of the MIF gene in individuals previously described with juvenile idiopathic arthritis and 22q11.2 deletion seems unlikely since it is located in the distal and less-frequently deleted region of 22q11.2 deletion syndrome.

Multicentric carpotarsal osteolysis syndrome with variants of MAFB gene: a case report and literature review

BACKGROUND

Multicentric carpotarsal osteolysis (MCTO) is a rare genetic disorder characterized by the progressive loss of bone in the hands, feet, and other skeletal structures. It presents with symptoms that may resemble those of juvenile idiopathic arthritis, making diagnosis challenging for clinicians. The identification of MAF BZIP Transcription Factor B (MAFB) mutations as significant contributors to MCTO represents a major breakthrough in our understanding of the pathogenesis of this rare skeletal disorder.

CASE PRESENTATION

Our objective was to present the phenotype, treatment, and outcome of a patient with a variant of MAFB-induced MCTO to broaden the range of clinical features associated with MCTO and share our clinical experience for improved diagnosis and treatment. In our case, early MRI examination of the bones and whole exome sequencing enabled an early and accurate MCTO diagnosis, and timely Denosumab administration resulted in no deterioration.

CONCLUSION

This suggests that MRI examination and whole exome sequencing should be considered when MCTO is suspected, and Denosumab might be an option in the treatment of MCTO.

Phenotype of Takayasu-like vasculitis and cardiopathy in patients with Blau syndrome

OBJECTIVES

We aimed to determine the prevalence of cardiovascular involvement in our Blau syndrome (BS) cohort and provide detailed analysis of their cardiovascular manifestations and outcome. We also tried to find out the risk factors for developing cardiovascular involvement.

METHODS

Clinical manifestations, laboratory findings, and treatments were reviewed. Clinical features were compared between children with cardiovascular involvement and those without angiocardiopathy.

RESULTS

A total of 38 BS children were eligible for final analysis. Among them, 13 (34.2%) developed Takayasu-like vasculitis and/or cardiopathy. Compared with those without angiocardiopathy, recurrent fever was more frequent in BS patients with cardiovascular involvement (p < 0.001). What is more, tumor necrosis factor alpha antagonists (anti-TNF) were more urgently needed in children with cardiovascular involvement (p = 0.015). BS patients with cardiovascular involvement include 4 with Takayasu-like vasculitis and 9 with cardiopathy. The onset of cardiovascular manifestations ranged from 0.75 to 18.5 years of age, with most cases occurring before school period. Symptoms were elusive and lacked specificity, such as dizziness, short of breath, and edema. Some patients were even identified because of the unexpected hypertension during follow-up. Cardiopathy and vasculitis occurred in patients with different genotypes. Imaging changes were discovered before the presentation of the typical triad in 3/4 patients with Takayasu-like vasculitis. Three children developed left ventricular dysfunction with decreased left ventricular ejection fraction. Combination of glucocorticoids and methotrexate with anti-TNF agents is a common treatment option for these BS patients. In the cohort, BS-related cardiovascular involvement was controlled well, with cardiac structural and functional abnormalities completely recovered and slower progression of vasculitis lesions.

CONCLUSION

Cardiovascular manifestations is not rare in BS patients. Because of its insidious onset, a systematic and comprehensive assessment of cardiovascular involvement should be performed in newly diagnosed patients with BS. Aggressive initiation of anti-TNF agents may be beneficial to improve the prognosis. Key Points • About 34.2% patients with Blau syndrome developed Takayasu-like vasculitis and/or cardiopathy. • Compared with those without angiocardiopathy, recurrent fever and application of anti-TNF agents were more frequent in BS patients with cardiovascular involvement (p < 0.001, p = 0.015) • Regular assessment of cardiovascular involvement is extremely necessary because of its insidious onset.

Inborn Errors of Immunity and Autoimmune Disease

Autoimmunity may be a manifestation of inborn errors of immunity, specifically as part of the subgroup of primary immunodeficiency known as primary immune regulatory disorders. However, although making a single gene diagnosis can have important implications for prognosis and management, picking patients to screen can be difficult, against a background of a high prevalence of autoimmune disease in the population. This review compares the genetics of common polygenic and rare monogenic autoimmunity, and explores the molecular mechanisms, phenotypes, and inheritance of autoimmunity associated with primary immune regulatory disorders, highlighting the emerging importance of gain-of-function and non-germline somatic mutations. A novel framework for identifying rare monogenic cases of common diseases in children is presented, highlighting important clinical and immunologic features that favor single gene disease and guides clinicians in selecting appropriate patients for genomic screening. In addition, there will be a review of autoimmunity in non-genetically defined primary immunodeficiency such as common variable immunodeficiency, and of instances where primary autoimmunity can result in clinical phenocopies of inborn errors of immunity.