Schimke immuno-osseous dysplasia: a newly recognized multisystem disease

Mitochondrial function in schimke-immunoosseous dysplasia

Schimke-immunoosseous dysplasia (SIOD) is a multisystemic disorder caused by a mutation of a putative chromatin remodelling protein. Spondyloepiphyseal dysplasia with disproportionate growth deficiency, nephrotic syndrome with focal and segmental glomerulosclerosis, defective cellular immunity, and transient ischemic attacks are major clinical features in the severe form of SIOD. In the present study we tested the hypothesis that mitochondrial dysfunction may be an underlying pathophysiologic mechanism in this multisystemic disease. Mitochondrial parameters were studied in blood (lactate, pyruvate, ketone bodies, alanine) and in urine (organic acids) of four patients with the severe form of SIOD. Activities of respiratory chain enzymes were measured spectrophotometrically in fibroblasts of two of these patients. In patients with the severe form of SIOD normal concentrations of lactate as well as normal lactate/pyruvate- and ketone-body ratios were found in plasma. Alanine, the long-term parameter for lactate, was normal as well; metabolites of the citrate cycle were not found in the urine. Activities of respiratory chain enzymes I-V were not significantly reduced in fibroblasts from two patients with the severe form of SIOD. There was no evidence for mitochondrial dysfunction in SIOD. The underlying pathophysiology of SIOD remains unclear.

Association of migraine-like headaches with Schimke immuno-osseous dysplasia

Schimke immuno-osseous dysplasia (SIOD) is characterized by spondyloepiphyseal dysplasia, nephropathy, and T-cell deficiency. SIOD is caused by mutations in the putative chromatin remodeling protein SMARCAL1. We report an 8-year-old boy with SIOD and recurrent, severe, refractory migraine-like headaches. Through a retrospective questionnaire-based study, we found that refractory and severely disabling migraine-like headaches occur in nearly half of SIOD patients. We have also found that the vasodilator minoxidil provided symptomatic relief for one patient. We hypothesize that these headaches may arise from an intrinsic vascular, neuroimmune, or neurovascular defect resulting from loss of SMARCAL1 function.

Fatal lymphoproliferative disorder in a child with Schimke immuno-osseous dysplasia

Schimke immuno-osseous dysplasia (SIOD) is a rare autosomal recessive disorder characterized by spondyloepiphyseal dysplasia, nephrotic syndrome, and cell-mediated immunodeficiency. Mutations in the SMARCAL1 gene (SW1/SNF2-related, matrix-associated, actin-dependent regulator of chromatin, subfamily a-like1) cause SIOD. We report a patient with SIOD and SMARCAL1 mutations, who presented with fever of unknown origin secondary to B-cell lymphoma. To our knowledge, this is the first report of an SIOD patient with a primary lymphoproliferative disorder (LPD).

Schimke-immuno-osseous dysplasia: New mutation with weak genotype-phenotype correlation in siblings

Schimke-immuno-osseous dysplasia (SIOD) is a multisystem disorder with the following consistent clinical features: spondyloepiphyseal dysplasia with disproportional growth deficiency, nephrotic syndrome with focal and segmental glomerulosclerosis, and defective cellular immunity. Transitory ischemic attacks due to vaso-occlusive processes are complications in some patients with severe SIOD. Recently, mutations of SMARCAL1, which encodes a putative chromatin remodelling protein, have been associated with SIOD. Patients with milder disease were observed to harbor a missense mutation on each allele, whereas patients with a severe form of the disease were predicted to have at least one allele with a nonsense, frameshift or splicing mutation. We report two brothers who are both compound heterozygous for the mutations 836 T>C and 2542 G>T detected in exons 4 and 17, respectively. We demonstrate the lack of genotype-phenotype correlation in these patients as one brother shows some features of the severe form while the other does not. Neither clinical nor molecular findings can fully predict the clinical course of SIOD.

Syndromic immunodeficiencies: genetic syndromes associated with immune abnormalities

In syndromic immunodeficiencies, clinical features not directly associated with the immune defect are prominent. Patients may present with either infectious complications or extra-immune medical issues. In addition to the immunologic abnormality, a wide range of organ systems may be affected. Patients may present with disturbances in skeletal, neurologic, dermatologic, or gastrointestinal function or development. These conditions can be caused by developmental abnormalities, chromosomal aberrations, metabolic disorders, or teratogens. For a number of these conditions, recent advances have resulted in an enhanced understanding of their genetic basis. The finding of immune deficits in a number of defined syndromes with congenital anomalies suggests that an underlying genetic syndrome should be considered in those patients in whom a significant non-immune feature is present.

Chicken collagen X regulatory sequences restrict transgene expression to hypertrophic cartilage in mice

Collagen X is produced by hypertrophic cartilage undergoing endochondral ossification. Transgenic mice expressing defective collagen X under the control of 4.7- or 1.6-kb chicken collagen X regulatory sequences yielded skeleto-hematopoietic defects (Jacenko O, LuValle P, Olsen BR: Spondylometaphyseal dysplasia in mice carrying a dominant-negative mutation in a matrix protein specific for cartilage-to-bone transition. Nature 1993, 365:56-61; Jacenko O, Chan D, Franklin A, Ito S, Underhill CB, Bateman JF, Campbell MR: A dominant interference collagen X mutation disrupts hypertrophic chondrocyte pericellular matrix and glycosaminoglycan and proteoglycan distribution in transgenic mice. Am J Pathol 2001, 159:2257-2269; Jacenko O, Roberts DW, Campbell MR, McManus PM, Gress CJ, Tao Z: Linking hematopoiesis to endochondral ossification through analysis of mice transgenic for collagen X. Am J Pathol 2002, 160:2019-2034). Current data indicate that the hematopoietic abnormalities do not result from extraskeletal expression of endogenous collagen X or the transgene. Organs from mice carrying either promoter were screened by immunohistochemistry, in situ hybridization, and Northern blot; transgene and mouse collagen X proteins and messages were detected only in hypertrophic cartilage. Likewise, reverse transcriptase-polymerase chain reaction revealed both transgene and mouse collagen X amplicons only in the endochondral skeleton of mice with the 4.7-kb promoter; however, in mice with the 1.6-kb promoter, multiple organs were transgene-positive. Collagen X and transgene amplicons were also detected in marrow, but likely resulted from contaminating trabecular bone; this was supported by reverse transcriptase-polymerase chain reaction analysis of rat tibial zones free of trabeculae. Our data demonstrate that in mice, the 4.7-kb chicken collagen X promoter restricts transcription temporo-spatially to that of endogenous collagen X, and imply that murine skeleto-hematopoietic defects result from transgene co-expression with collagen X. Moreover, the 4.7-kb hypertrophic cartilage-specific promoter could be used for targeting transgenes to this tissue site in mice.

Schimke immuno-osseous dysplasia: two cases

We report two patients with Schimke immuno-osseous dysplasia (SIOD). SIOD is characterised by growth retardation, renal failure, spondylo-epiphyseal dysplasia, specific phenotype and defective cellular immunity. These two children demonstrated a bone dysplasia with characteristic radiographic appearances. We postulate that SIOD should be considered in all cases of growth failure with an unclassifiable bone dysplasia. Repeated urine tests for proteinuria could be helpful in reaching the correct diagnosis.

Linking hematopoiesis to endochondral skeletogenesis through analysis of mice transgenic for collagen X

Each skeletal element where marrow develops is first defined by a hypertrophic cartilage blueprint. Through programmed tissue substitution, the cartilaginous skeletal model is replaced by trabecular bone and marrow, with accompanying longitudinal tissue growth. During this process of endochondral ossification, hypertrophic cartilage expresses a unique matrix molecule, collagen X. Previously we reported that transgenic mice with dominant interference collagen X mutations develop variable skeleto-hematopoietic abnormalities, manifested as growth plate compressions, diminished trabecular bone, and reduced lymphatic organs (Nature 1993, 365:56). Here, histology and flow cytometry reveal marrow hypoplasia and impaired hematopoiesis in all collagen X transgenic mice. A subset of mice with perinatal lethality manifested the most severe skeletal defects and a reduction of marrow hematopoiesis, highlighted by a lymphocyte decrease. Thymic reduction is accompanied by a paucity of cortical immature T cells, consistent with the marrow's inability to replenish maturing cortical lymphocytes. Diminished spleens exhibit indistinct lymphatic nodules and red pulp depletion; the latter correlates with erythrocyte-filled vascular sinusoids in marrows. All mice display reduced B cells in marrows and spleens, and elevated splenic T cells. These hematopoietic defects underscore an unforeseen link between hypertrophic cartilage, endochondral ossification, and establishment of the marrow microenvironment required for blood cell differentiation.

Mutant chromatin remodeling protein SMARCAL1 causes Schimke immuno-osseous dysplasia

Schimke immuno-osseous dysplasia (SIOD, MIM 242900) is an autosomal-recessive pleiotropic disorder with the diagnostic features of spondyloepiphyseal dysplasia, renal dysfunction and T-cell immunodeficiency. Using genome-wide linkage mapping and a positional candidate approach, we determined that mutations in SMARCAL1 (SWI/SNF2-related, matrix-associated, actin-dependent regulator of chromatin, subfamily a-like 1), are responsible for SIOD. Through analysis of data from persons with SIOD in 26 unrelated families, we observed that affected individuals from 13 of 23 families with severe disease had two alleles with nonsense, frameshift or splicing mutations, whereas affected individuals from 3 of 3 families with milder disease had a missense mutation on each allele. These observations indicate that some missense mutations allow retention of partial SMARCAL1 function and thus cause milder disease.

A dominant interference collagen X mutation disrupts hypertrophic chondrocyte pericellular matrix and glycosaminoglycan and proteoglycan distribution in transgenic mice

Collagen X transgenic (Tg) mice displayed skeleto-hematopoietic defects in tissues derived by endochondral skeletogenesis.(1) Here we demonstrate that co-expression of the transgene product containing truncated chicken collagen X with full-length mouse collagen X in a cell-free translation system yielded chicken-mouse hybrid trimers and truncated chicken homotrimers; this indicated that the mutant could assemble with endogenous collagen X and thus had potential for dominant interference. Moreover, species-specific collagen X antibodies co-localized the transgene product with endogenous collagen X to hypertrophic cartilage in growth plates and ossification centers; proliferative chondrocytes also stained diffusely. Electron microscopy revealed a disrupted hexagonal lattice network in the hypertrophic chondrocyte pericellular matrix in Tg growth plates, as well as altered mineral deposition. Ruthenium hexamine trichloride-positive aggregates, likely glycosaminoglycans (GAGs)/proteoglycans (PGs), were also dispersed throughout the chondro-osseous junction. These defects likely resulted from transgene co-localization and dominant interference with endogenous collagen X. Moreover, altered GAG/PG distribution in growth plates of both collagen X Tg and null mice was confirmed by a paucity of staining for hyaluronan and heparan sulfate PG. A provocative hypothesis links the disruption of the collagen X pericellular network and GAG/PG decompartmentalization to the potential locus for hematopoietic failure in the collagen X mice.

Successful bone marrow transplantation in a patient with Schimke immuno-osseous dysplasia

Early death in Schimke immuno-osseous dysplasia often results from renal failure and/or cell-mediated immunodeficiency. Kidney transplants have improved renal function, but effective therapy for the immunodeficiency has not yet been reported. We describe markedly improved marrow function 2 years after bone marrow transplantation in a boy with Schimke immunoosseous dysplasia.

Dental findings in the Schimke immuno-osseous dysplasia

Schimke immuno-osseous dysplasia is a rare autosomal recessive disorder that affects primarily bone, T lymphocytes, kidneys, and skin. The patients have a triangular face, broad nasal bridge, bulbous nose tip, small palpebral fissures, short neck, long upper lip, and low hairline. Dental abnormalities of affected patients have not been discussed in detail. The patient described in this clinical report presented with clinical and radiographic abnormalities that may constitute a diagnostic characteristic in this condition.

A syndrome involving intrauterine growth retardation, microcephaly, cerebellar hypoplasia, B lymphocyte deficiency, and progressive pancytopenia

We report a new complex syndrome involving profound failure to thrive with severe intrauterine growth retardation, cerebellar abnormalities, microcephaly, a complete lack of B lymphocyte development, and secondary, progressive marrow aplasia. B cell differentiation was found to be blocked at the pro-B cell stage. Although not strictly proven, a genetic origin is likely, according to similar cases reported in the literature. Three candidate genes, PAX5, encoding B cell-specific activator protein, a factor involved in B cell lineage commitment, stromal cell-derived factor 1, and CXCR4, encoding a chemokine and its receptor, respectively, were thought to be responsible for this disease, given the similarity between the phenotype of the corresponding knock-out mice and the clinical features of the patient. However, the genomic DNA sequences of these 3 genes were normal, and normal amounts of stromal cell-derived factor 1 and CXCR4 were present. These data strongly suggest that another molecule is involved in early B cell differentiation, hematopoiesis, and cerebellar development in humans.

Mental retardation and seizure disorder in Schimke immunoosseous dysplasia

Schimke immunoosseous dysplasia (SID) is a rare, pleiotropic disorder compromising spondyloepiphyseal dysplasia, nephrotic syndrome, defective T-cell-mediated immunity, and vascular changes which can lead to cerebral infarcts. The cause is unknown but an autosomal recessive inheritance pattern has been suggested. Understanding of the clinical phenotype is evolving; however, the neurologic spectrum is not well known. We report on a 17-year-old woman who presented with behavior changes, developmental regression, and partial complex seizures in early childhood. Computed tomographic scan of the brain was normal at that time. Short stature and cognitive deficits became evident several months later. At 4 1/2 years, she developed nephrotic syndrome and later malignant hypertension. Recent magnetic resonance imaging of the brain showed focal encephalomalacia in the parietal regions and a magnetic resonance angiography documented narrowing of the middle cerebral arteries. A skeletal survey showed evidence of spondyloepiphyseal dysplasia. We have not been able to identify an immune defect. To our knowledge this is the first reported patient with SID, profound mental retardation, and a seizure disorder. This case supports the theory that an intrinsic vascular defect may be more important in the pathogenesis of SID than a T-cell-mediated immune deficit.

Schimke immunoosseous dysplasia complicated by moyamoya phenomenon

Schimke immunoosseous dysplasia (SID) is an autosomal recessive spondyloepiphyseal dysplasia that was first described by Schimke et al. [1971: Lancet 2:1088-1089]. It is associated with premature arteriosclerosis and cerebral ischemia; however, the cerebral vascular abnormalities causing ischemia have not been described [Spranger et al., 1991: J Pediatr 119:64-72; Ehrich et al., 1995: Clin Nephrol 43:89-95]. Based on magnetic resonance angiography (MRA) and magnetic resonance venography (MRV), we now report on 2 girls with SID who have cerebral ischemia associated with moyamoya phenomenon. In addition, one patient also has an absent or occluded left transverse sinus and diffuse aortic narrowing. This is the first characterization of the cerebral vascular abnormality found in SID and raises the possibility that cerebral moyamoya may represent another major manifestation of the underlying genetic defect in SID.

Spondylo-mesomelic-acrodysplasia with joint dislocations and severe combined immunodeficiency: a newly recognised immuno-osseous dysplasia

A newborn girl is described with an association of spondylo-acrodysplasia, mild short limbed dwarfism without significant metaphyseal changes, joint dislocations, and severe immune system dysfunction. This association is distinct from other known immuno-osseous dysplasias, including Schimke dysplasia, ADA deficiency with osseous changes, and Omenn phenotype with short limbed dwarfism.

Immunodeficiency as a component of recognizable syndromes

Immunodeficiency occurs in numerous genetic syndromes. While it is the dominant manifestation in primary immunodeficiencies, immune deficits may also be seen in a variety of other recognizable syndromes. Immunodeficiency has been reported in 64 such conditions, adding to the 45 recognized primary immunodeficiencies. These uncommon syndromes with immune defects can present with: (a) growth deficiency (11 syndromes with disproportionate or proportionate short stature), (b) specific organ system dysfunction (18 with gastrointestinal, dermatologic, or neurologic abnormalities), (c) inborn errors of metabolism (13), (d) miscellaneous anomalies (10), or (e) chromosome anomalies (12). In most of the disorders, only some of the affected patients have immune defects. However, in 27 syndromes, immunodeficiency is a constant finding. We briefly review the clinical manifestations of each syndrome and delineate the specific associated immune defects. In most syndromes, the connection between the immune and other defects is unknown. Recognition of these conditions involving both the immune and other organ systems may facilitate accurate diagnosis and management as well as yield information regarding genes critical for the development of the involved systems.

Spondyloepiphyseal dysplasia tarda and nephrotic syndrome in three siblings

The association of a spondyloepiphyseal dysplasia tarda (SED-T) with the nephrotic syndrome (NS) was found in three siblings. They have counsaguineous (first cousins) healthy parents. Patient 1 was a boy who was admitted to hospital for oedema at the age of 8 years; NS was diagnosed, renal biopsy revealed mesangioproliferative glomerulonephritis. After 4 years he developed end-stage renal failure and died whilst on haemodialysis. Combined therapy with cyclophosphamide and prednisone was of no benefit. At the age of 11 years his height was 122 cm (< 3rd percentile -3.2 SD); he had a short neck, broad and prominent chest and a short wide trunk. Patient 2, another male, had non-nephrotic proteinuria in a 24-h urinary sample at the age of 11 years; this was confirmed in a later analysis; mild lymphopenia and a reduction of helper T cell (OKT4)/suppressor T cell (OKT8) ratio was also detected. At 22 years of age he was admitted to hospital with end-stage renal failure. He was on haemodialysis for a few months until his mother donated a kidney. At the age of 22 years his height was 157 cm (< 3rd percentile), he had a short trunk with the thoracic cage increased in anteroposterior diameter and shoulder elevation. Roentgenograms revealed a disostosis of the spinal column and pelvis and a slight lombar platyspondylia. Patient 3, a girl, was admitted to hospital at 12.5 years for pain and restricted mobility of the right hip. X-rays showed deep acetabula and short femoral necks and mild dysplastic changes, especially in the right hip.(ABSTRACT TRUNCATED AT 250 WORDS)

Juvenile variant of Schimke immunoosseous dysplasia

We report on a 16-year-old girl with spondyloepiphyseal dysplasia, nephrotic syndrome, lymphopenia, and signs of defective cellular immunity. The manifestations are very similar to those reported by Spranger et al. [1991: J. Pediatr 119: 64-72] as Schimke immunoosseous dysplasia, except for age of onset. In Schimke immunoosseous dysplasia, growth retardations as an initial symptom is noted in early childhood and about 1 year after onset of progressive proteinuria. In our case the skeletal abnormality was noted at age 10 years as dislocation of the hip joints and the diagnosis of nephrotic syndrome was made at age 16 years. The findings strongly suggest that our patient has a juvenile variant of Schimke immunoosseous dysplasia.

Spondyloepiphyseal dysplasia with nephrotic syndrome (Schimke immunoosseous dysplasia)

The first symptoms of immunooseous dysplasia were growth retardation and myopia. Nephrotic syndrome was diagnosed at the age of 8 years. Skeletal roentgenograms showed spondyloepiphyseal dysplasia. In the renal biopsy there was nodular accumulations of PAS-positive hyaline material at the base of the granular stalks. There was lymphopenia with decreased CD4 and CD8 subpopulations. The condition of the patient gradually worsened until she died unexpectedly at 10 years with clinical symptoms of encephalitis. Autopsy documented cytomegaloviral pneumonia and advanced mesangioproliferative glomerulonephritis. In the spleen there was PAS-positive hyaline material massively infiltrating the walls of the central arterioles of the splenic follicles. There was marked depletion of lymphocytes in the spleen and in lymph nodes. The differential diagnosis of immunooseous dysplasia in the framework of spondyloepiphyseal dysplasia is discussed.

Schimke immuno-osseous dysplasia: case report and review

We report on a patient with Schimke immunoosseous dysplasia, an autosomal recessive disorder, and review nine patients from the literature. Manifestations include spondyloepiphyseal dysplasia, lymphopenia, signs of defective cellular immunity, and progressive renal disease. This is the first patient known to have the additional findings of thrombocytopenia and microdontia.