Schimke Immuno-osseous Dysplasia Research Articles

Different growth patterns in two siblings with Schimke immuno-osseous-dysplasia.

Schimke immuno-osseous-dysplasia (SIOD) is an autosomal recessive systemic disease due to pathogenic variants in SMARCAL1. Manifestations include nephrotic syndrome (NS), kidney failure, T-cell dysfunction, vaso-occlusive disease, and disproportionate short stature, a general feature of this disease. Here, we present a markedly different growth pattern in two brothers with SIOD sharing the same homozygous R561C missense variant. The index patient presented at the age of 11years with NS and severely disproportionate short stature, followed by kidney failure at the age of 16, and severely reduced adult height (z-score - 8.0). In contrast, the younger brother showed normal growth until the age of 8years. Mild proteinuria was noted at the age of 4.5, followed by NS at 9.5years, kidney failure at 11years, progressive disproportionate stature, and reduced adult height (z-score - 4.5). Both brothers had comparable disproportion in adulthood (sitting height index z-score - 0.88 and - 1.44, respectively).

Profound T Lymphocyte and DNA Repair Defect Characterizes Schimke Immuno-Osseous Dysplasia

Schimke immuno-osseous dysplasia is a rare multisystemic disorder caused by biallelic loss of function of the SMARCAL1 gene that plays a pivotal role in replication fork stabilization and thus DNA repair. Individuals affected from this disease suffer from disproportionate growth failure, steroid resistant nephrotic syndrome leading to renal failure and primary immunodeficiency mediated by T cell lymphopenia. With infectious complications being the leading cause of death in this disease, researching the nature of the immunodeficiency is crucial, particularly as the state is exacerbated by loss of antibodies due to nephrotic syndrome or immunosuppressive treatment. Building on previous findings that identified the loss of IL-7 receptor expression as a possible cause of the immunodeficiency and increased sensitivity to radiation-induced damage, we have employed spectral cytometry and multiplex RNA-sequencing to assess the phenotype and function of T cells ex-vivo and to study changes induced by in-vitro UV irradiation and reaction of cells to the presence of IL-7. Our findings highlight the mature phenotype of T cells with proinflammatory Th1 skew and signs of exhaustion and lack of response to IL-7. UV light irradiation caused a severe increase in the apoptosis of T cells, however the expression of the genes related to immune response and regulation remained surprisingly similar to healthy cells. Due to the disease’s rarity, more studies will be necessary for complete understanding of this unique immunodeficiency.

Expanding the Clinical Features of Schimke Immuno-Osseous Dysplasia: A New Patient with a Novel Variant and Novel Clinical Findings.

Schimke Immuno-Osseous Dysplasia (SIOD) (MIM:242900) is an ultra-rare autosomal recessive pan-ethnic pleiotropic disease. Typical findings of this syndrome are steroid-resistant nephrotic syndrome, cellular immunodeficiency and spondyloepiphyseal dysplasia and facial dysmorphism. Biallelic variants in the SMARCAL1 gene cause SIOD. The five-and-half-year-old female patient was evaluated because of short stature, dysmorphism, hypercalcemia, hypophosphatemia and elevated FSH levels. Karyotype analysis and array-CGH testing were normal. Clinical Exome Sequencing was performed via next-generation sequencing to analyze genes associated with hypophosphatemia. No pathogenic variant was detected. The subsequent detection of proteinuria during her follow-up for cross-fused ectopic left kidney ultimately facilitated the diagnosis of SIOD, although no obvious spondyloepiphyseal dysplasia was detected. Re-analysis of CES revealed a novel homozygous c.2422_2427+9delinsA pathogenic variant in the SMARCAL1. One hundred twenty-five SIOD cases from 38 literature reporting SMARCAL1 gene pathogenic variants were reviewed to investigate whether hypercalcemia, hypophosphatemia and elevated FSH levels had been previously reported in SIOD patients. This review revealed that this was the first time these findings had been reported in a SIOD patient. This report expands not only the phenotypic but also genotypic spectrum of SIOD.

44 Optimization of care for a patient with Schimke Immuno-Osseous Dysplasia (SIOD)

44 Optimization of care for a patient with Schimke Immuno-Osseous Dysplasia (SIOD)

Loss of helicase C-terminal domain of SMARCAL1 protein associated with severe Schimke immuno-osseous dysplasia

Schimke immuno-osseous dysplasia (SIOD) is a rare multi-system condition caused by biallelic loss-of-function mutations in the SMARCAL1 gene. This disorder is characterized by disproportionate growth failure, T-cell deficiency, and renal dysfunction. Pathogenic variants in the SMARCAL1 gene have been reported in only approximately half of SIOD-affected individuals. Among these alterations, nonsense and frameshift mutations generally lead to a severe phenotype with early onset. In this study, we identified novel mutations in an Iranian patient with SIOD. A 4-year-old girl with developmental delay and facial dysmorphism was referred to our center for molecular diagnosis. We applied whole-exome and Sanger sequencing for co-segregation analysis. Subsequently, bioinformatic analysis was performed to assess the pathogenic effects of the variants and their post-transcriptional effects. We discovered two novel mutations (c.2281delT and c.2283delA) in exon 15 of the SMARCAL1 gene, resulting in a truncated protein with a loss of 193 amino acids (p.S761Rfs*1). Variant effect predictors indicated that these variants are pathogenic, and multi-sequence alignments revealed high conservation of this region among different species. Given that our patient exhibited severe a phenotype and passed away soon after receiving a definitive molecular diagnosis, we propose that the loss of the helicase C-terminal domain in the deleted part of SMARCAL1 may lead to the severe form of SIOD. Besides, the combination of growth retardation and bone abnormalities also plays a crucial role in the early diagnosis of the disease.

Chromatin regulator SMARCAL1 modulates cellular lipid metabolism

Biallelic mutations of the chromatin regulator SMARCAL1 cause Schimke Immunoosseous Dysplasia (SIOD), characterized by severe growth defects and premature mortality. Atherosclerosis and hyperlipidemia are common among SIOD patients, yet their onset and progression are poorly understood. Using an integrative approach involving proteomics, mouse models, and population genetics, we investigated SMARCAL1’s role. We found that SmarcAL1 interacts with angiopoietin-like 3 (Angptl3), a key regulator of lipoprotein metabolism. In vitro and in vivo analyses demonstrate SmarcAL1’s vital role in maintaining cellular lipid homeostasis. The observed translocation of SmarcAL1 to cytoplasmic peroxisomes suggests a potential regulatory role in lipid metabolism through gene expression. SmarcAL1 gene inactivation reduces the expression of key genes in cellular lipid catabolism. Population genetics investigations highlight significant associations between SMARCAL1 genetic variations and body mass index, along with lipid-related traits. This study underscores SMARCAL1’s pivotal role in cellular lipid metabolism, likely contributing to the observed lipid phenotypes in SIOD patients.

The odontoblastic differentiation of dental mesenchymal stem cells: molecular regulation mechanism and related genetic syndromes.

Dental mesenchymal stem cells (DMSCs) are multipotent progenitor cells that can differentiate into multiple lineages including odontoblasts, osteoblasts, chondrocytes, neural cells, myocytes, cardiomyocytes, adipocytes, endothelial cells, melanocytes, and hepatocytes. Odontoblastic differentiation of DMSCs is pivotal in dentinogenesis, a delicate and dynamic process regulated at the molecular level by signaling pathways, transcription factors, and posttranscriptional and epigenetic regulation. Mutations or dysregulation of related genes may contribute to genetic diseases with dentin defects caused by impaired odontoblastic differentiation, including tricho-dento-osseous (TDO) syndrome, X-linked hypophosphatemic rickets (XLH), Raine syndrome (RS), hypophosphatasia (HPP), Schimke immuno-osseous dysplasia (SIOD), and Elsahy-Waters syndrome (EWS). Herein, recent progress in the molecular regulation of the odontoblastic differentiation of DMSCs is summarized. In addition, genetic syndromes associated with disorders of odontoblastic differentiation of DMSCs are discussed. An improved understanding of the molecular regulation and related genetic syndromes may help clinicians better understand the etiology and pathogenesis of dentin lesions in systematic diseases and identify novel treatment targets.

Schimke immuno-osseous dysplasia in a boy with generalized edema; a case report

Schimke immuno-osseous dysplasia (SIOD) is a rare disease diagnosed by skeletal malformations, steroid-resistant nephrotic syndrome (SRNs), and T-cell immunodeficiency. Proteinuria with focal segmental glomerulosclerosis (FSGS) is the most common renal pathologic finding in SIOD. In this case report, we present an 8-year-old boy with generalized edema, kyphosis, and nephrotic syndrome who was eventually diagnosed with SIOD.

Schimke immunoosseous dysplasia: a multisystem disorder

Schimke immunoosseous dysplasia is an autosomal recessive disorder characterized by spondyloepiphyseal dysplasia, lymphopenia with defective cellular immunity, and renal insufficiency. It is caused by a biallelic mutation in SMARCAL 1 gene. In this study, we described clinical and genetic diagnosis of a 5 years old girl who presented to our centre with short stature and repeated infections in the past. She had one episode of stroke in the past due to infarction and she was diagnosed with hypertension 1 year back. Last admission in the hospital, she had new stroke episode and found to have steroid resistant nephrotic syndrome.

Hereditary dentin defects with systemic diseases.

This review aimed to summarize recent progress on syndromic dentin defects, promoting a better understanding of systemic diseases with dentin malformations, the molecules involved, and related mechanisms. References on genetic diseases with dentin malformations were obtained from various sources, including PubMed, OMIM, NCBI, and other websites. The clinical phenotypes and genetic backgrounds of these diseases were then summarized, analyzed, and compared. Over 10 systemic diseases, including osteogenesis imperfecta, hypophosphatemic rickets, vitamin D-dependent rickets, familial tumoral calcinosis, Ehlers-Danlos syndrome, Schimke immuno-osseous dysplasia, hypophosphatasia, Elsahy-Waters syndrome, Singleton-Merten syndrome, odontochondrodysplasia, and microcephalic osteodysplastic primordial dwarfism type II were examined. Most of these are bone disorders, and their pathogenic genes may regulate both dentin and bone development, involving extracellular matrix, cell differentiation, and metabolism of calcium, phosphorus, and vitamin D. The phenotypes of these syndromic dentin defects various with the involved genes, part of them are similar to dentinogenesis imperfecta or dentin dysplasia, while others only present one or two types of dentin abnormalities such as discoloration, irregular enlarged or obliterated pulp and canal, or root malformation. Some specific dentin defects associated with systemic diseases may serve as important phenotypes for dentists to diagnose. Furthermore, mechanistic studies on syndromic dentin defects may provide valuable insights into isolated dentin defects and general dentin development or mineralization.

WCN23-1097 Primary steroid resistant nephrotic syndrome as part of Schimke-immunoosseous dysplasia features in a girl: a case report

WCN23-1097 Primary steroid resistant nephrotic syndrome as part of Schimke-immunoosseous dysplasia features in a girl: a case report

Schimke immunoosseous dysplasia: an ultra-rare disease. a 20-year case series from the tertiary hospital in the Czech Republic

BackgroundSchimke immunoosseous dysplasia (SIOD) is an ultra-rare inherited disease affecting many organ systems. Spondyloepiphyseal dysplasia, T-cell immunodeficiency and steroid resistant nephrotic syndrome are the main symptoms of this disease.Case presentationWe aimed to characterize the clinical, pathological and genetic features of SIOD patients received at tertiary Pediatric Nephrology Center, University Hospital Motol, Prague, Czech Republic during the period 2001–2021. The mean age at diagnosis was 21 months (range 18–48 months). All patients presented with growth failure, nephropathy and immunodeficiency. Infections and neurologic complications were present in most of the affected children during the course of the disease.ConclusionsAlthough SIOD is a disease characterized by specific features, the individual phenotype may differ. Neurologic signs can severely affect the quality of life; the view on the management of SIOD is not uniform. Currently, new therapeutic methods are required.

Moyamoya syndrome in Schimke immuno-osseous dysplasia

Introduction. Schimke immuno-osseous dysplasia (SIOD) is a rare autosomal recessive multisystem disorder associated with biallelic mutations of the SMAR-CAL1 gene. Vascular central nervous system complications in the form of Moyamoya syndrome (MMS) have been reported as a comorbidity in nearly half of the patients clinically presenting with severe migraine-like headaches, transient ischemic attacks (TIA), and ischemic or hemorrhagic infarctions. We present an illustrative case of an infantile form of SIOD with MMS, with a review of the latest diagnostic possibilities, as well as current diagnostic and therapeutic dilemmas in managing SIOD. Case report. We present a female patient with the infantile form of SIOD. The proband was born small for gestational age in the 34th gestation week with characteristic dysmorphic features. Genetic testing found a biallelic, nonsense mutation c.2542G>T in the SMARCAL1 gene. The patient presented early with TIA, seizures, and recurrent ischemic strokes. Magnetic resonance imaging (MRI) confirmed the presence of progressive brain atrophy with bilateral occlusion/stenosis of middle cerebral artery and anterior cerebral artery and a smoke-like collateral vessel appearance consistent with the MMS. At the age of 5 years and 9 months, the patient developed a high fever and cough with unknown cause, with a low erythrocyte and white blood cell count during four weeks, with a poor therapeutic response to antibiotics, transfusion of red blood cells, and granulocyte growth factor. She later died. Conclusion. Patients with SIOD may present progressive cerebral vascular changes and clinical neurologic deterioration early in the course of the disease. In such patients, early diagnosis and preventive revascularization surgery are of paramount importance. In diagnosing MMS, MRI angiography can be an appropriate substitute for standard invasive cerebral angiography.

Stem cell-kidney transplantation in Schimke immuno-osseous dysplasia.

Stem cell-kidney transplantation in Schimke immuno-osseous dysplasia.

Sequential Stem Cell–Kidney Transplantation in Schimke Immuno-osseous Dysplasia

SummaryLifelong immunosuppression is required for allograft survival after kidney transplantation but may not ultimately prevent allograft loss resulting from chronic rejection. We developed an approach that attempts to abrogate immune rejection and the need for post-transplantation immunosuppression in three patients with Schimke immuno-osseous dysplasia who had both T-cell immunodeficiency and renal failure. Each patient received sequential transplants of αβ T-cell–depleted and CD19 B-cell–depleted haploidentical hematopoietic stem cells and a kidney from the same donor. Full donor hematopoietic chimerism and functional ex vivo T-cell tolerance was achieved, and the patients continued to have normal renal function without immunosuppression at 22 to 34 months after kidney transplantation. (Funded by the Kruzn for a Kure Foundation.)

On the Interaction Between SMARCAL1 and BRG1.

SMARCAL1 and BRG1, both classified as ATP-dependent chromatin remodeling proteins, play a role in double-strand break DNA damage response pathways. Mutations in SMARCAL1 cause Schimke Immuno-osseous Dysplasia (SIOD) while mutations in BRG1 are associated with Coffin-Siris Syndrome (CSS4). In HeLa cells, SMARCAL1 and BRG1 co-regulate the expression of ATM, ATR, and RNAi genes on doxorubicin-induced DNA damage. Both the proteins are found to be simultaneously present on the promoter of these genes. Based on these results we hypothesized that SMARCAL1 and BRG1 interact with each other forming a complex. In this paper, we validate our hypothesis and show that SMARCAL1 and BRG1 do indeed interact with each other both in the absence and presence of doxorubicin. The formation of these complexes is dependent on the ATPase activity of both SMARCAL1 and BRG1. Using deletion constructs, we show that the HARP domains of SMARCAL1 mediate interaction with BRG1 while multiple domains of BRG1 are probably important for binding to SMARCAL1. We also show that SIOD-associated mutants fail to form a complex with BRG1. Similarly, CSS4-associated mutants of BRG1 fail to interact with SMARCAL1, thus, possibly contributing to the failure of the DNA damage response pathway and pathophysiology associated with SIOD and CSS4.

Neurological symptoms in Schimke immuno-osseous dysplasia in a 11-year-old girl: a case report

Background: Schimke immuno-osseous dysplasia (SIOD, OMIM 242900) is a rare, autosomal recessive, pleiotropic disease caused by mutations in the SMARCAL1 gene. SIOD is characterized by a triad of symptoms, i.e., progressive kidney disease due to focal segmen- tal glomerulosclerosis (FSGS), spondyloepiphyseal dysplasia and T-cell immunodeficiency. Additionally, heterogeneous neurological symptoms are often observed in the course of the syndrome. Case: The authors describe the case of a 14-year-old girl with SIOD, who presented with recurrent neurological symptoms, such as migraine-like headaches, diplopia and seizures. She was born at 34 weeks of pregnancy with hypotrophy (1280 g) and short stature (44 cm). Nephrotic-range proteinuria, the first symptom of the disease, was detected at the age of 4 and a half years. Significant immunodeficiency was also observed. She was finally diagnosed with Schimke immuno-osseous dysplasia on account of two pat- hogenic variants, c.836T>C (p.F279S) and c.2542G>T (p.E848X) identified in the SMARCAL1 gene. Conclusions: This report describes the clinical features and neuroimaging findings of a patient with SIOD. It also presents a possible correlation between neurological events and the Schimke disease, which should be considered during the diagnostic process.

Neurološki simptomi u Schimkeovoj imuno-koštanoj displaziji u 11-godišnje djevojčice: prikaz slučaja

Background: Schimke immuno-osseous dysplasia (SIOD, OMIM 242900) is a rare, autosomal recessive, pleiotropic disease caused by mutations in the SMARCAL1 gene. SIOD is characterized by a triad of symptoms, i.e., progressive kidney disease due to focal segmen- tal glomerulosclerosis (FSGS), spondyloepiphyseal dysplasia and T-cell immunodeficiency. Additionally, heterogeneous neurological symptoms are often observed in the course of the syndrome. Case: The authors describe the case of a 14-year-old girl with SIOD, who presented with recurrent neurological symptoms, such as migraine-like headaches, diplopia and seizures. She was born at 34 weeks of pregnancy with hypotrophy (1280 g) and short stature (44 cm). Nephrotic-range proteinuria, the first symptom of the disease, was detected at the age of 4 and a half years. Significant immunodeficiency was also observed. She was finally diagnosed with Schimke immuno-osseous dysplasia on account of two pat- hogenic variants, c.836T>C (p.F279S) and c.2542G>T (p.E848X) identified in the SMARCAL1 gene. Conclusions: This report describes the clinical features and neuroimaging findings of a patient with SIOD. It also presents a possible correlation between neurological events and the Schimke disease, which should be considered during the diagnostic process.

Functional Immune Tolerance Induced By Sequential Hematopoietic Stem Cell-Solid Organ Transplantation

Solid organ transplantation (SOT) treats over 1500 children/year in the US. While short-term outcomes have improved, long-term outcomes still remain poor. With the rare exception of monozygotic twins as donors, recipients require lifelong immunosuppression with its accompanying toxicities, the risk of nonadherence, and chronic rejection. Further, up to half of recipients require a second transplant.We have pioneered translational approaches that abrogate rejection and the need for post-transplant immunosuppression. Previous attempts in adult patients utilizing allogeneic hematopoietic stem cell transplantation (HSCT) to eliminate the need for post-SOT immunosuppression in non-histocompatible kidney transplant (KT) recipients have failed(Lowsky R, BMT 2019). The establishment of mixed lymphoid chimerism has permitted a reduction in the number of immunosuppressive drugs needed, but not their discontinuation, whereas complete donor engraftment after HSCT has resulted in fatal graft-versus-host disease in some patients (Leventhal JR, Eur J Pediatr 2000). The use of HSCT to eliminate the need for immunosuppression following pediatric KT has not been evaluated. We have pioneered sequential haploidentical HSCT followed by KT in three patients with Schimke immuno-osseous dysplasia (SIOD) to abrogate kidney rejection and the need for post-transplant immunosuppression.SIOD is a monogenic disorder with progressive nephropathy correctable by KT and a T-cell immunodeficiency curable by HSCT. All three patients received αβT-cell/CD19 B-cell depleted HSCT (αβhaplo-HSCT) from a parent prior to a KT from the same parental donor. The pre-HSCT reduced intensity preparative regimen consisted of fludarabine (a starting dose of 1 mg/kg x 4 days, which was adjusted based on AUC), total body irradiation (TBI) 200 cGy, cyclophosphamide 1200 mg/m 2, anti-thymocyte globulin (ATG) thymoglobulin® 7.5 mg/kg, and rituximab 200 mg/m 2. Immunosuppressive drugs were not prophylactically administered after HSCT. After confirmation of full donor lymphoid chimerism post-HSCT, the patients received a living donor KT from their parental HSCT donor. Post-KT immunosuppression included intraoperative methylprednisolone and post-operative low-dose oral prednisone (0.5 mg/kg/day with taper) and tacrolimus (target serum level of 3-5 ng/ml) to reduce potential reperfusion inflammation. All immunosuppressive drugs were tapered off by Day +30 post-KT. To demonstrate functional tolerance after KT, Mixed Lymphocyte Cultures (MLC) were performed between peripheral blood mononuclear cells (PBMC) and patient/parent-derived irradiated EBV transformed lymphoblastoid cells lines (EBV-LCL) as stimulators (Figure 1). PBMC were isolated from SIOD patients (n=3) by Ficoll Hypaque separation and were labelled with Invitrogen™ CellTrace Violet Proliferation Kit (CTV). EBV-LCL were established from SIOD patients, parents and healthy donors. The assay was performed in round bottom microtiter plates with 100,000 labelled PBMC as responder cells (R) and 50,000 irradiated (30gy) EBV-LCL in RPMI medium with 10% fetal calf serum. Cells were harvested on Day 6, and T-cell proliferation determined by CTV expression of CD3+ T cells using a Novocyte Penteon flow cytometer (Agilent).Donor-derived T cells isolated from the peripheral blood of all three recipients > 1-year post-HSCT/KT, did not respond to the donor cells, while they did proliferate to the non-donor parental and control cells (Fig. 1). These results demonstrate that post-HSCT/KT the circulating donor-derived T cells are functionally tolerant to the transplanted kidney and, therefore, are unable to mediate graft rejection even in the absence of immune suppression. We have achieved two goals: first, ablating the recipient immune system before HSCT we safely established a new donor-derived immune system - that could also, if required, cure a patient's underlying disease- and, second, functional tolerance to the transplanted kidney.At 12 to 24 months after KT, all patients have full donor lymphoid and myeloid chimerism, normal renal function without immunosuppression, MLC demonstrated tolerance towards donor cells, and normal proliferative responses to non-donor parental cells. These findings suggest that the combination of αβhaplo-HSCT and SOT could be extended to other solid transplantation like liver and small intestine. [Display omitted] DisclosuresBertaina: Cellevolve Bio: Membership on an entity's Board of Directors or advisory committees; Neovii: Membership on an entity's Board of Directors or advisory committees; AdicetBio: Membership on an entity's Board of Directors or advisory committees. Shah: OrchardTherapeutics: Membership on an entity's Board of Directors or advisory committees, Other: Dr. Shah currently serves on the medical advisory board for Orchard Therapeutics . Parkman: Jasper Biotech: Consultancy.

A Case of Schimke Immunoosseous Dysplasia Caused by Large Deletion of SMARCAL1 Gene.

A Case of Schimke Immunoosseous Dysplasia Caused by Large Deletion of SMARCAL1 Gene.