Monogenic lupus due to spondyloenchondrodysplasia with spastic paraparesis and intracranial calcification: case-based review

Macrocephaly and Finger Changes: A Narrative Review

Macrocephaly, characterized by an abnormally large head circumference, often co-occurs with distinctive finger changes, presenting a diagnostic challenge for clinicians. This review aims to provide a current synthetic overview of the main acquired and genetic etiologies associated with macrocephaly and finger changes. The genetic cause encompasses several categories of diseases, including bone marrow expansion disorders, skeletal dysplasias, ciliopathies, inherited metabolic diseases, RASopathies, and overgrowth syndromes. Furthermore, autoimmune and autoinflammatory diseases are also explored for their potential involvement in macrocephaly and finger changes. The intricate genetic mechanisms involved in the formation of cranial bones and extremities are multifaceted. An excess in growth may stem from disruptions in the intricate interplays among the genetic, epigenetic, and hormonal factors that regulate human growth. Understanding the underlying cellular and molecular mechanisms is important for elucidating the developmental pathways and biological processes that contribute to the observed clinical phenotypes. The review provides a practical approach to delineate causes of macrocephaly and finger changes, facilitate differential diagnosis and guide for the appropriate etiological framework. Early recognition contributes to timely intervention and improved outcomes for affected individuals.

Rare SH2B3 coding variants in lupus patients impair B cell tolerance and predispose to autoimmunity

Systemic lupus erythematosus (SLE) is a heterogeneous autoimmune disease with a clear genetic component. While most SLE patients carry rare gene variants in lupus risk genes, little is known about their contribution to disease pathogenesis. Amongst them, SH2B3-a negative regulator of cytokine and growth factor receptor signaling-harbors rare coding variants in over 5% of SLE patients. Here, we show that unlike the variant found exclusively in healthy controls, SH2B3 rare variants found in lupus patients are predominantly hypomorphic alleles, failing to suppress IFNGR signaling via JAK2-STAT1. The generation of two mouse lines carrying patients' variants revealed that SH2B3 is important in limiting the number of immature and transitional B cells. Furthermore, hypomorphic SH2B3 was shown to impair the negative selection of immature/transitional self-reactive B cells and accelerate autoimmunity in sensitized mice, at least in part due to increased IL-4R signaling and BAFF-R expression. This work identifies a previously unappreciated role for SH2B3 in human B cell tolerance and lupus risk.

Autoimmune Hemolytic Anemia Due to Spondyloenchondrodysplasia with Spastic Paraparesis and Intracranial Calcification due to Mutation in ACP5

Spondyloenchondrodysplasia (SPENCD) is a rare spondylometaphyseal skeletal dysplasia with characteristic lesions mimicking enchondromatosis and resulting in short stature. A large spectrum of immunologic abnormalities may be seen in SPENCD, including immune deficiencies and autoimmune disorders. SPENCD is caused by loss of tartrate-resistant acid phosphatase activity, due to homozygous mutations in ACP5 , playing a role in nonnucleic-acid-related stimulation/regulation of the type I interferon pathway. In this article, we presented a 19-year-old boy with SPENCD, presenting with recurrent autoimmune hemolytic anemia episodes since he was 5 years old. He had short stature, platyspondyly, metaphyseal changes, intracranial calcification, spastic paraparesis, and mild intellectual disability. He also had recurrent pneumonia attacks. The clinical diagnosis of SPENCD was confirmed by sequencing of the ACP5 gene, and a homozygous c.155A > C (p.K52T) variation was found, which was reported before as pathogenic. In conclusion, in early onset chronic autoimmune cytopenias an immune dysregulation may often have a role in the etiology. Associating findings and immunologic functions should be carefully evaluated in such patients in the light of the literature. The present case shows the importance of multisystemic evaluation for the detection of SPENCD that has a monogenic etiology.

Bilateral cochlear implants in a case of spondyloenchondrodysplasia with sensorineural hearing loss: Case report

INTRODUCTION

Spondyloenchondrodysplasia (SPENCD) is a rare autosomal recessive skeletal dysplasia caused by acid phosphates 5 gene mutation. SPENCD has multisystemic manifestations including enchondromas in the long bones or pelvis, skeletal anomalies, immune dysfunctions, and neurological impairments. Out of the wide spectrum of presentation in SPENCD, hearing loss is one of the least presented symptoms.

CASE PRESENTATION

Here we present a two-year-old female, who visited the otolaryngology clinic concerned about hearing and delayed speech. The patient was started on hearing aids, later was diagnosed with SPENCD by pedatrics department. After a discussion with the family, the patient underwent a bilateral cochlear implant for sensorineural hearing loss at the age of four, which went uneventfully.

CLINICAL DISCUSSION

Children with skeletal dysplasias have abnormal tympanometry indicating a higher likelihood of middle ear disease and conductive hearing loss. A result of a hearing screening program done in 2010 showed that 25 % of children with skeletal dysplasia have hearing loss at least in 1 ear, and 50 % of them had abnormal tympanometry featuring middle ear dysfunction. Uncontrolled immune system response in autoimmune diseases commonly causes bilateral SNHL. However, the exact defect, in this case, is still unknown if it is cochlear or central.

CONCLUSION

The objective of this report is to highlight the unusual presentation of profound sensorineural hearing loss in a pediatric case with SPENCD that was managed with cochlear implants.

Case report: Refractory Evans syndrome in two patients with spondyloenchondrodysplasia with immune dysregulation treated successfully with JAK1/JAK2 inhibition

Biallelic mutations in the ACP5 gene cause spondyloenchondrodysplasia with immune dysregulation (SPENCDI). SPENCDI is characterized by the phenotypic triad of skeletal dysplasia, innate and adaptive immune dysfunction, and variable neurologic findings ranging from asymptomatic brain calcifications to severe developmental delay with spasticity. Immune dysregulation in SPENCDI is often refractory to standard immunosuppressive treatments. Here, we present the cases of two patients with SPENCDI and recalcitrant autoimmune cytopenias who demonstrated a favorable clinical response to targeted JAK inhibition over a period of more than 3 years. One of the patients exhibited steadily rising IgG levels and a bone marrow biopsy revealed smoldering multiple myeloma. A review of the literature uncovered that approximately half of the SPENCDI patients reported to date exhibited increased IgG levels. Screening for multiple myeloma in SPENCDI patients with rising IgG levels should therefore be considered.

Monogenic lupus: Tracing the therapeutic implications from single gene mutations

Monogenic lupus, a distinctive variant of systemic lupus erythematosus (SLE), is characterized by early onset, family-centric clustering, and heightened disease severity. So far, over thirty genetic variations have been identified as single-gene etiology of SLE and lupus-like phenotypes. The critical role of these gene mutations in disrupting various immune pathways is increasingly recognized. In particular, single gene mutation-driven dysfunction within the innate immunity, notably deficiencies in the complement system, impedes the degradation of free nucleic acid and immune complexes, thereby promoting activation of innate immune cells. The accumulation of these components in various tissues and organs creates a pro-inflammatory microenvironment, characterized by a surge in pro-inflammatory cytokines, chemokines, reactive oxygen species, and type I interferons. Concurrently, single gene mutation-associated defects in the adaptive immune system give rise to the emergence of autoreactive T cells, hyperactivated B cells and plasma cells. The ensuing spectrum of cytokines and autoimmune antibodies drives systemic disease manifestations, primarily including kidney, skin and central nervous system-related phenotypes. This review provides a thorough overview of the single gene mutations and potential consequent immune dysregulations in monogenic lupus, elucidating the pathogenic mechanisms of monogenic lupus. Furthermore, it discusses the recent advances made in the therapeutic interventions for monogenic lupus.

Genes and Microbiota Interaction in Monogenic Autoimmune Disorders

Monogenic autoimmune disorders represent an important tool to understand the mechanisms behind central and peripheral immune tolerance. Multiple factors, both genetic and environmental, are known to be involved in the alteration of the immune activation/immune tolerance homeostasis typical of these disorders, making it difficult to control the disease. The latest advances in genetic analysis have contributed to a better and more rapid diagnosis, although the management remains confined to the treatment of clinical manifestations, as there are limited studies on rare diseases. Recently, the correlation between microbiota composition and the onset of autoimmune disorders has been investigated, thus opening up new perspectives on the cure of monogenic autoimmune diseases. In this review, we will summarize the main genetic features of both organ-specific and systemic monogenic autoimmune diseases, reporting on the available literature data on microbiota alterations in these patients.

Current views on lupus in children

PURPOSE OF REVIEW

This manuscript provides an update on clinical and pathophysiological features of juvenile-onset systemic lupus erythematosis (jSLE), challenges applying adult-derived classification criteria, and recent advances in treatment and care.

RECENT FINDINGS

Significant scientific advances have improved the understanding of genetic factors (both genetic causes and risk alleles) and associated phenotypic features. Panels of urine/blood biomarker candidates aid in diagnosing jSLE, monitoring disease activity and predicting treatment response. Available classification criteria have been extensively assessed, with differences in clinical and immunological phenotypes of patients across age groups and ethnicities affecting their performance in jSLE. Therapeutic options remain limited and are based on protocols for adult-onset SLE patients. International efforts to inform development of a treat-to-target (T2T) approach for jSLE have yielded cohort-level evidence that target attainment reduces the risk of severe flare and new damage, and treatment compliance.

SUMMARY

Recent studies have significantly improved our understanding of jSLE pathogenesis, highlighting important differences between jSLE and adult SLE, and providing the basis of biomarker development and target-directed individualized treatment and care. Future work focused on development of a T2T approach in jSLE is eagerly awaited.

Spondyloenchondrodysplasia Due to Mutation in ACP5 Gene Presenting with Nephrotic Syndrome: A Case Report

Spondyloenchondrodysplasia (SPENCD) with immune dysregulation (SPENCDI) is a rare autosomal recessive inherited immuno-osseous dysplasia characterized by spondylo-metaphyseal enchondromas, along with immune dysregulation ranging from immunodeficiency to autoimmune disorder. Here, we present two cousins with ACP5 gene mutation who had severe short stature with mild hypogammaglobulinemia, nephrotic syndrome, autoimmune thyroiditis and cerebral calcification (Case 1); and in the other (Case 2), there was no clinical findings other than severe short stature, CD4+−T cell lymphopenia and non-autoimmune compensated hypothyroidism. We wanted to emphasize that monogenic causes should be considered in the etiology of early-onset nephrotic syndrome due to the detection of a mutation in the ACP5 gene (her actual diagnosis was changed to SPENCDI.) 5 years after the diagnosis of nephrotic syndrome in the first case, and that the renal involvement may occur without SLE in patients with ACP5 mutation. Severe short stature was a common finding in both cases. We underlined that the clinic can be different even in the same mutation, due to the absence of cerebral calcification and renal involvement in the second case, which is a cousin with Case 1. As a result, endocrinologists, immunologists, rheumatologists, nephrologists and orthopedists should be aware of this syndrome, because SPENCDI causes a pleiotropic (due to more than one phenotypic effect of a gene) clinical picture. Severe short stature may be the only presenting sign of patients with SPENCDI. In addition, in the presence of early-onset nephrotic syndrome and autoimmune thyroiditis, the patient should be evaluated for this type of monogenic disorders as well.

Type I interferon-related kidney disorders

Type I interferon (IFN-I) mediates tissue damage in a wide range of kidney disorders, directly affecting the biology and function of several renal cell types including podocytes, mesangial, endothelial and parietal epithelial cells (PECs).Enhanced IFN-I signalling is observed in the context of viral infections, autoimmunity (e.g., systemic lupus erythematosus, SLE), and the type 1 interferonopathies (T1Is), rare monogenic disorders characterised by constitutive activation of the IFN-I pathway. All of these IFN I-related disorders can cause renal dysfunction, and share pathogenic and histopathological features. Collapsing glomerulopathy, a histopathological lesion characterised by podocyte loss, collapse of the vascular tuft and PEC proliferation, is commonly associated with viral infections, has been described in T1Is such as Aicardi-Goutières syndrome and STING-associated vasculopathy with onset in infancy (SAVI), and can also be induced by recombinant IFN-therapy. In all of these conditions, podocytes and PECs seem to be the primary target of IFN I-mediated damage. Additionally, immune-mediated glomerular injury is common to viral infections, SLE, and T1Is such as COPA syndrome and DNASE1L3 deficiency, diseases in which IFN-I apparently promotes immune-mediated kidney injury. Finally, kidney pathology primarily characterised by vascular lesions (e.g., thrombotic microangiopathy, vasculitis) is a hallmark of the T1I ADA2 deficiency as well as of SLE, viral infections and IFN-therapy.Defining the nosology, pathogenic mechanisms and histopathological patterns of IFN I-related kidney disorders has diagnostic and therapeutic implications, especially considering the likely near-term availability of novel drugs targeting the IFN-I pathway.

Genetic screening of early-onset patients with systemic lupus erythematosus by a targeted next-generation sequencing gene panel

OBJECTIVE

In this study, we aimed to screen 31 genes (C1QA, C1QB, C1QC, C1R, C1S, C2, C3, TREX1, RNASEH2A, RNASEH2B, RNASEH2C, SAMHD1, ADAR, DNASE1, DNASE1L3, PRKCD, ACP5, SLC7A7, IFIH1, TMEM173, ISG15, CYBB, FAS, FASLG, KRAS, NRAS, MAN2B1, PEPD, PTPN11, RAG2, and SHOC2), that we have categorized under the umbrella term "monogenic lupus" using a targeted next-generation sequencing (NGS) panel in 24 individuals with early-onset (≤10 years of age) systemic lupus erythematosus (SLE) and in 24 patients with late-onset (>10 years of age) disease.

METHODS

A total of 48 SLE patients (24 with disease onset ≤10 years of age and 24 with disease onset >10 years of age) were included. Patients with late-onset disease have been used as patient controls. Sequencing was carried out using 400 bp kit on the Ion S5 system.

RESULTS

Among the 48 patients, three had one pathogenic variant and 45 patients had at least one rare variant classified as benign, likely benign or variant of unknown significance (VUS). In all three patients with a pathogenic variant, the onset of disease was before 10 years of age. Two patients (they were siblings) carried C1QA homozygote pathogenic allele (p.Gln208Ter, rs121909581), and one patient carried PEPD heterozygote pathogenic allele (p.Arg184Gln, rs121917722).

CONCLUSION

We demonstrated a pathogenic variant in our target gene panel with a frequency of 9.52% in patients with a disease onset ≤10 years of age. All patients with early-onset SLE phenotype, irrespective of a positive family history for SLE or parental consanguinity, should be scanned for a single-gene defect by a targeted gene panel sequencing. With the discovery of many single-gene defects and ongoing efforts to identify novel genes in SLE, similar gene panels including even more genes will possibly become more necessary and practical in the future.

Neuroinflammation Associated With Inborn Errors of Immunity

The advent of high-throughput sequencing has facilitated genotype-phenotype correlations in congenital diseases. This has provided molecular diagnosis and benefited patient management but has also revealed substantial phenotypic heterogeneity. Although distinct neuroinflammatory diseases are scarce among the several thousands of established congenital diseases, elements of neuroinflammation are increasingly recognized in a substantial proportion of inborn errors of immunity, where it may even dominate the clinical picture at initial presentation. Although each disease entity is rare, they collectively can constitute a significant proportion of neuropediatric patients in tertiary care and may occasionally also explain adult neurology patients. We focus this review on the signs and symptoms of neuroinflammation that have been reported in association with established pathogenic variants in immune genes and suggest the following subdivision based on proposed underlying mechanisms: autoinflammatory disorders, tolerance defects, and immunodeficiency disorders. The large group of autoinflammatory disorders is further subdivided into IL-1β-mediated disorders, NF-κB dysregulation, type I interferonopathies, and hemophagocytic syndromes. We delineate emerging pathogenic themes underlying neuroinflammation in monogenic diseases and describe the breadth of the clinical spectrum to support decisions to screen for a genetic diagnosis and encourage further research on a neglected phenomenon.

Novel Mutations in ACP5 and SAMHD1 in a Patient With Pediatric Systemic Lupus Erythematosus

BACKGROUND

The study of genetic predisposition to pediatric systemic lupus erythematosus (pSLE) has brought new insights into the pathophysiology of SLE, as it is hypothesized that genetic predisposition is greater in children. Furthermore, identifying genetic variants and linking disrupted genes to abnormal immune pathways and clinical manifestations can be beneficial for both diagnosis and treatment. Here, we identified genetic alterations in a patient with childhood-onset SLE and analyzed the immunological mechanisms behind them to support future diagnosis, prognosis, and treatment.

METHODS

Whole exome sequencing (WES) was adopted for genetic analysis of a patient with childhood-onset SLE. Gene mutations were confirmed by Sanger sequencing. Clinical data of this patient were collected and summarized. Ingenuity Pathway Analysis was used to provide interacting genes of the perturbed genes. Online Enrichr tool and Cytoscape software were used to analysis the related pathways of these genes.

RESULTS

We present a case of a 2-year-old girl who was diagnosed with idiopathic thrombocytopenic purpura (ITP) and SLE. The patient was characterized by cutaneous bleeding spots on both lower extremities, thrombocytopenia, decreased serum complements levels, increased urinary red blood cells, and positive ANA and dsDNA. The patient was treated with methylprednisolone and mycophenolate, but clinical remission could not be achieved. The genomic analysis identified three novel mutations in this pSLE patient, a double-stranded missense mutation in ACP5 (c.1152G>T and c.420G>A) and a single-stranded mutation in SAMHD1 (c.1423G>A). Bioinformatic analysis showed that these two genes and their interacting genes are enriched in the regulation of multiple immune pathways associated with SLE, including cytokine signaling and immune cell activation or function. Analysis of the synergistic regulation of these two genes suggests that abnormalities in the type I interferon pathway caused by genetic variants may contribute to the pathogenesis of SLE.

CONCLUSION

The combined complexity of polymorphisms in the coding regions of ACP5 and SAMHD1 influences the susceptibility to SLE. Alterations in these genes may lead to abnormalities in the type I interferon pathway. Our study extends the spectrum of mutations in the ACP5 and SAMHD1 genes. The identification of these mutations could aid in the diagnosis of SLE with genetic counseling and suggest potential precise treatments for specific pathways.

Systemic lupus erythematosus - Are children miniature adults?

Systemic lupus erythematosus (SLE) is a systemic autoimmune/inflammatory disease that can affect any organ system and cause significant damage and organ failure. Disease-onset during childhood (juvenile-onset SLE) is associated with less typical autoantibody patterns, diffuse organ involvement, more damage already at diagnoses, and a higher need of immunomodulating treatment, including corticosteroids, when compared to adult-onset SLE. Differences in the molecular pathophysiology within SLE, and over-representation of patients with "genetic SLE" contribute to differences in clinical presentation and treatment responses between children and adults. This manuscript summarizes currently available literature focusing on parallels and differences between clinical pictures, known pathomechanisms, and available treatment options in juvenile- versus adult-onset SLE.

[Systemic lupus erythematosus-are children small adults?]

Systemic lupus erythematosus (SLE) is a systemic inflammatory disease that can affect any organ of the human body and cause significant damage. As compared to patients with adult-onset SLE, children and young people (juvenile SLE) more frequently experience extensive diffuse organ involvement, more organ damage at diagnoses, and resistance to immunomodulatory treatment. This manuscript emphasizes parallels and differences between the clinical pictures, known pathomechanisms, and available treatment options of juvenile and adult-onset SLE.