Clinical and radiological findings in Schinzel-Giedion syndrome

Whole-genome sequencing combined RNA-sequencing analysis of patients with mutations in SET binding protein 1

SET binding protein 1 (SETBP1) is essential for human development, and pathogenic germline variants in SETBP1 lead to a recognizable developmental syndrome and variable clinical features. In this study, we assessed a patient with facial dysmorphism, intellectual disability and delayed motor development. Whole genome sequencing identified a novel de novo variation of the SETBP1 (c.2631C > A; p. S877R) gene, which is located in the SKI domain, as a likely pathogenic variant for the proband’s phenotype. RNA sequencing was performed to investigate the potential molecular mechanism of the novel variation in SETBP1. In total, 77 and 38 genes were identified with aberrant expression and splicing, respectively. Moreover, the biological functions of these genes were involved in DNA/protein binding, expression regulation, and the cell cycle, which may advance our understanding of the pathogenesis of SETBP1 in vivo.

SETBP1 accumulation induces P53 inhibition and genotoxic stress in neural progenitors underlying neurodegeneration in Schinzel-Giedion syndrome

The investigation of genetic forms of juvenile neurodegeneration could shed light on the causative mechanisms of neuronal loss. Schinzel-Giedion syndrome (SGS) is a fatal developmental syndrome caused by mutations in the SETBP1 gene, inducing the accumulation of its protein product. SGS features multi-organ involvement with severe intellectual and physical deficits due, at least in part, to early neurodegeneration. Here we introduce a human SGS model that displays disease-relevant phenotypes. We show that SGS neural progenitors exhibit aberrant proliferation, deregulation of oncogenes and suppressors, unresolved DNA damage, and resistance to apoptosis. Mechanistically, we demonstrate that high SETBP1 levels inhibit P53 function through the stabilization of SET, which in turn hinders P53 acetylation. We find that the inheritance of unresolved DNA damage in SGS neurons triggers the neurodegenerative process that can be alleviated either by PARP-1 inhibition or by NAD + supplementation. These results implicate that neuronal death in SGS originates from developmental alterations mainly in safeguarding cell identity and homeostasis.

Overlapping SETBP1 gain-of-function mutations in Schinzel-Giedion syndrome and hematologic malignancies

Schinzel-Giedion syndrome (SGS) is a rare developmental disorder characterized by multiple malformations, severe neurological alterations and increased risk of malignancy. SGS is caused by de novo germline mutations clustering to a 12bp hotspot in exon 4 of SETBP1. Mutations in this hotspot disrupt a degron, a signal for the regulation of protein degradation, and lead to the accumulation of SETBP1 protein. Overlapping SETBP1 hotspot mutations have been observed recurrently as somatic events in leukemia. We collected clinical information of 47 SGS patients (including 26 novel cases) with germline SETBP1 mutations and of four individuals with a milder phenotype caused by de novo germline mutations adjacent to the SETBP1 hotspot. Different mutations within and around the SETBP1 hotspot have varying effects on SETBP1 stability and protein levels in vitro and in in silico modeling. Substitutions in SETBP1 residue I871 result in a weak increase in protein levels and mutations affecting this residue are significantly more frequent in SGS than in leukemia. On the other hand, substitutions in residue D868 lead to the largest increase in protein levels. Individuals with germline mutations affecting D868 have enhanced cell proliferation in vitro and higher incidence of cancer compared to patients with other germline SETBP1 mutations. Our findings substantiate that, despite their overlap, somatic SETBP1 mutations driving malignancy are more disruptive to the degron than germline SETBP1 mutations causing SGS. Additionally, this suggests that the functional threshold for the development of cancer driven by the disruption of the SETBP1 degron is higher than for the alteration in prenatal development in SGS. Drawing on previous studies of somatic SETBP1 mutations in leukemia, our results reveal a genotype-phenotype correlation in germline SETBP1 mutations spanning a molecular, cellular and clinical phenotype.

Neuroimaging Findings in Pediatric Genetic Skeletal Disorders: A Review

Genetic skeletal disorders (GSDs) are a heterogeneous group characterized by an intrinsic abnormality in growth and (re-)modeling of cartilage and bone. A large subgroup of GSDs has additional involvement of other structures/organs beside the skeleton, such as the central nervous system (CNS). CNS abnormalities have an important role in long-term prognosis of children with GSDs and should consequently not be missed. Sensitive and specific identification of CNS lesions while evaluating a child with a GSD requires a detailed knowledge of the possible associated CNS abnormalities. Here, we provide a pattern-recognition approach for neuroimaging findings in GSDs guided by the obvious skeletal manifestations of GSD. In particular, we summarize which CNS findings should be ruled out with each GSD. The diseases (n = 180) are classified based on the skeletal involvement (1. abnormal metaphysis or epiphysis, 2. abnormal size/number of bones, 3. abnormal shape of bones and joints, and 4. abnormal dynamic or structural changes). For each disease, skeletal involvement was defined in accordance with Online Mendelian Inheritance in Man. Morphological CNS involvement has been described based on extensive literature search. Selected examples will be shown based on prevalence of the diseases and significance of the CNS involvement. CNS involvement is common in GSDs. A wide spectrum of morphological abnormalities is associated with GSDs. Early diagnosis of CNS involvement is important in the management of children with GSDs. This pattern-recognition approach aims to assist and guide physicians in the diagnostic work-up of CNS involvement in children with GSDs and their management.

Schinzel-Giedion syndrome in two Brazilian patients: Report of a novel mutation in SETBP1 and literature review of the clinical features

Schinzel-Giedion syndrome is a rare autosomal dominant disorder comprising postnatal growth failure, profound developmental delay, seizures, facial dysmorphisms, genitourinary, skeletal, neurological, and cardiac defects. It was recently revealed that Schinzel-Giedion syndrome is caused by de novo mutations in SETBP1, but there are few reports of this syndrome with molecular confirmation. We describe two unrelated Brazilian patients with Schinzel-Giedion syndrome, one of them carrying a novel mutation. We also present a review of clinical manifestations of the syndrome, comparing our cases to patients reported in literature emphasizing the importance of the facial gestalt associated with neurological involvement for diagnostic suspicion of this syndrome.

[Schinzel-Giedion syndrome: a new mutation in SETBP1]

Schinzel-Giedion syndrome (SGS) (#MIM 269150) is a rare genetic disorder characterized by very marked craniofacial dysmorphism, multiple congenital anomalies and severe intellectual disability. Most affected patients die in early childhood. SETBP1 was identified as the causative gene, but a limited number of patients with molecular confirmation have been reported to date. The case is reported of a 4 and a half year-old male patient, affected by SGS. SETBP1 sequencing analysis revealed the presence of a non-previously described mutation: c.2608G>T (p.Gly870Cys). The clinical features and differential diagnosis of this rare condition are reviewed. Dysmorphic features are strongly suggestive of SGS. Its clinical recognition is essential to enable an early diagnosis, a proper follow-up, and to provide the family with genetic counseling. To date, this is the seventeenth SGS patient published with SETBP1 mutation, and the first in Spain, helping to widen clinical and molecular knowledge of the disease.

Distinct neurological features in a patient with Schinzel-Giedion syndrome caused by a recurrent SETBP1 mutation

INTRODUCTION

Schinzel-Giedion syndrome (SGS) is a rare multiple congenital malformation syndrome defined by characteristic facial features, profound developmental delay, severe growth failure, and multiple congenital anomalies. Most individuals affected by SGS die in early childhood mainly because of progressive neurodegeneration and respiratory failure. The causative gene of SGS, SETBP1, was identified, but there are few reports of SGS with molecular confirmation worldwide.

PATIENT AND METHOD

In this study, we present a 10-month-old boy presenting with SGS complicated by epilepsy and profound developmental delay.

RESULTS

Typical facial features, multiple anomalies, and associated neurological findings suggested a clinical diagnosis of SGS. Unusually in our patient, generalized tonic seizure occurred and has been controlled well by combined antiepileptic therapy during 7 months of follow-up. Electroencephalography findings were compatible with partial seizures, and ventriculomegaly, thinning of the corpus callosum, and delayed myelination were identified on brain MR images. SETBP1 mutational analysis revealed the presence of a recurrent mutation, p.Gly870Ser. Thus, the diagnosis of our patient was molecularly confirmed as SGS.

CONCLUSIONS

Although this syndrome is extremely rare, it is important to consider SGS in the differential diagnosis of infantile-onset epilepsy with progressive neurodevelopmental retardation, especially in patients with multiple anomalies and facial dysmorphism.

Cobblestone lissencephaly in Schinzel-Giedion syndrome

The brain of a 5-year-old boy with Schinzel-Giedion syndrome displayed a cobblestone appearance of orbital and lateral aspects of frontal lobes due to widespread glioneuronal meningeal heterotopia. Meningeal heterotopia consisted of scattered neurons, neurofilament positive axons, and myelinated fibers accompanied by striking astrocytic gliosis. The underlying cortex showed gaps in the pial basal lamina, distorted neuronal layering, and focal polymicrogyria. The number of capillaries appeared increased throughout the brain. Mild hydrocephalus was associated with a slight atrophy of corpus callosum as well as villous hyperplasia and marked stromal degeneration of the choroid plexus. Our findings suggest that Schinzel-Giedion syndrome may represent One more entity within enlarging spectrum of lissencephalic cortical dysplasia syndromes.

Sacrococcygeal teratoma: the 13-year experience of a tertiary paediatric centre

AIM

To describe the management, morbidity and mortality of infants admitted to a tertiary paediatric hospital in New South Wales, Australia with a diagnosis of sacrococcygeal teratoma (SCT).

METHODS

All neonates admitted to the neonatal intensive care unit with a SCT between January 1996 and December 2008 were included in this retrospective review. Data collected included maternal and neonatal demographics, time of diagnosis, tumour characteristics, surgical treatment, operative complications and outcomes.

RESULTS

Seventeen infants with a diagnosis of SCT were included in the study. Of these infants, the majority (70%) were born at term, and eight had a prenatal diagnosis made during the second trimester. Associated anomalies were detected in seven infants (41.8%), with renal anomalies being the most common. Tumour histology included mature (50%, n= 8), yolk sac tumour (18.75%, n= 3), immature (6.25%, n= 1) and mature with mixed elements (25%, n= 4). Recurrent disease occurred in two infants within 4-18 months of the primary resection, with one infant suffering a second recurrence. Only one child died prior to surgery, giving a survival rate of 94%, and mean age at follow-up was 32 months. Long-term sequelae found in four babies included revision of scar, vesicoureteric reflux, post-surgical neurogenic bladder and osteotomy for hip dysplasia.

CONCLUSIONS

The overall survival of neonatal SCT is high. While this is a small series, our results are consistent with the literature. Important components of management include timely diagnosis, multidisciplinary planning, long-term follow-up and intervention for functional sequelae.