Spondylocostal dysostosis associated with diaphragmatic hernia and neural tube defects

Identification of a Novel Nonsense Variant in the DLL3 Gene Underlying Spondylocostal Dysostosis in a Consanguineous Pakistani Family

Introduction

Spondylocostal dysostosis (SCD) is characterized by multiple vertebral abnormalities associated with abnormalities of the ribs. Five genes causative for the disease have been identified. These include DLL3 (OMIM *602768), MESP2 (OMIM #608681), LFNG (OMIM #609813), TBX6 (OMIM *602427), and HES7 (OMIM *608059).

Methods

In the current study, we investigated a Pakistani consanguineous family segregating spondylocostal dysotosis. Whole-exome sequencing (WES) followed by Sanger sequencing was performed using DNA of affected and unaffected individuals to identify pathogenic variant(s). The identified variant was interpreted using ACMG classification. Literature review was performed to summarize currently known mutated alleles of DLL3 and the underlying clinical phenotypes.

Results

Clinical examination using anthropometric measurements and radiographs diagnosed the patients to be afflicted with SCD. Pedigree analysis of the affected family showed an autosomal recessive inheritance pattern of the disease. WES followed by Sanger sequencing identified a novel homozygous nonsense variant (DLL3(NM_016941.4): c.535G>T; p.Glu179Ter) in the DLL3 gene located on chromosome 19q13.2.

Conclusion

The study will be helpful in carrier testing and genetic counseling to prevent segregation of the disease to the next generations within this family. It also provides knowledge for clinicians and researchers in search of a better understanding of SCD anomalies.

Clinical genetics of spondylocostal dysostosis: A mini review

Spondylocostal dysostosis is a genetic defect associated with severe rib and vertebrae malformations. In recent years, extensive clinical and molecular diagnosis advancements enabled us to identify disease-causing variants in different genes for such severe conditions. The identification of novel candidate genes enabled us to understand the developmental biology and molecular and cellular mechanisms involved in the etiology of these rare diseases. Here, we discuss the clinical and molecular targets associated with spondylocostal dysostosis, including clinical evaluation, genes, and pathways involved. This review might help us understand the basics of such a severe disorder, which might help in proper clinical characterization and help in future therapeutic strategies.

Phenotypic heterogeneity of kyphoscoliosis with vertebral and rib defects: a case series

Disorders associated with multiple vertebral segmentation defects may have additional rib anomalies in form of absence or hypoplastic ribs, fanning of ribs, etc. Spondylocostal dysostosis is genetic disorder with abnormal vertebral segmentation and rib anomalies. Diagnosis is often delayed because of non-familiarity with the characteristic features. There are six genes identified for spondylocostal dysostosis, of which SCDO5 is responsible for autosomal dominant form of the disorder. Retrospective study was conducted in Genetic and Metabolic unit of a tertiary hospital in north India over a period of 9 years. Twenty patients with a clinical diagnosis of congenital scoliosis were identified, and reviewed. Three patients were discussed in an earlier report and 11 subsequent patients, are described in this case series here. The median age at presentation was 34 months. The patients showed hemivertebrae, vertebral fusion, fusion of ribs, fanning of ribs. Hydrocephalus/ventriculomegaly was found in three cases and diastematomyelia was identified in one case. Other associated anomalies included corpus callosal agenesis, club foot and capillary malformation. One parent showed rib/spinal defects in two cases. Further studies are needed to characterise the phenotype and genetic basis of scoliosis in Indian patients.

A Case of Fatal Pulmonary Hypoplasia with Congenital Diaphragmatic Hernia, Thoracic Myelomeningocele, and Thoracic Dysplasia

Background  Congenital diaphragmatic hernia (CDH) is fatal in severe cases of pulmonary hypoplasia. We experienced a fatal case of pulmonary hypoplasia due to CDH, thoracic myelomeningocele (MMC), and thoracic dysplasia. This constellation of anomalies has not been previously reported. Case Report  A male infant with a prenatal diagnosis of thoracic MMC with severe hydrocephalus and scoliosis was born at 36 weeks of gestation. CDH was found after birth and the patient died of respiratory failure due to pulmonary hypoplasia and persistent pulmonary hypertension of the newborn at 30 hours of age despite neonatal intensive care. An autopsy revealed a left CDH without herniation of the liver or stomach into the thoracic cavity, severe hydrocephalus, Chiari malformation type II, MMC with spina bifida from Th4 to Th12, hemivertebrae, fused ribs, deformities of the thoracic cage and legs, short trunk, and agenesis of the left kidney. Conclusion  We speculate that two factors may be associated with the severe pulmonary hypoplasia: decreased thoracic space due to the herniation of visceral organs caused by CDH and thoracic dysplasia due to skeletal deformity and severe scoliosis.

Statistical analysis of associated vertebra and costal anomalies in spina bifida patients

Objective: Spina bifida is one of the most severe birth defects and can happen as a result of disrupted primary neurulation. Congenital vertebra and costa anomalies are more frequently seen with spina bifida, and associated anomalies significantly affect the prognosis of affected children. In this study, we aimed to determine the incidence of scoliosis, costal anomalies, and vertebral deformations seen at the time of diagnosis and to statistically evaluate their concomitancies.

Methods: Gender and mean ages of the patients were determined. The spina bifida patients were examined for deformation anomalies, butterfly vertebra, hemivertebra, wedge vertebra, costal anomalies and scoliosis. The relationships between these anomalies were evaluated.

Results: 94 patients with a mean age of 11,5 months examined. The incidence of scoliosis was 21.8% among female infants and 17.9% among males. Rates of scoliosis with vertebra anomalies (hemivertebra, wedge vertebra) and costal anomalies did not differ significantly (P > 0.05). Wedge vertebra were the most frequent vertebra anomaly type with 38.2% ratio. Costal anomalies were detected in 25.5% of females and 20.5% of male infants. Hemivertebra and wedge vertebra were seen significantly more frequently in this group. Gender distribution did not differ between with and without any vertebra types.

Conclusion: Congenital vertebra and costa anomalies are more frequently seen with spina bifida. We believe that these anomalies and relationship with spina bifida may demonstrate differences among different ethnic groups or locations. More detailed multi-centered studies performed on this issue will aid in the determination of etiologies, genetics, and treatment principles of these congenital anomalies.

Mind the gap: an unusual case of a cervical lipomyelocele

Cervical dysraphism is rare, and the 3 recognized subtypes manifest as cystic, skin-covered masses. To our knowledge, no case of cervical lipomyelocele has been reported in the literature so far. We present a case of surgically and pathologically confirmed cervical lipomyelocele in a patient with spondylocostal dysostosis and multiple other congenital anomalies and a brief review of the literature. In this case, magnetic resonance imaging demonstrates fat extension into a dysraphic cervical spinal canal, allowing for preoperative diagnosis. Computed tomography using 3-dimensional reconstruction serves to more clearly characterize the extensive spine malsegmentation characteristic of spondylocostal dysostosis. The use of this technique is suggested to benefit the orthopedic or neurologic surgeon confronted with such complex malformations.

Spondylocostal dysostosis with lipomyelomeningocele: Case report and review of the literature

Spondylocostal dysostosis (SCDO) is rare anomaly caused due to flawed embryological development of the axial skeleton during preliminary stages of gravidity, characterized by malformed vertebral column and ribs, abridged thorax and kyphoscoliosis. This entity was also reported as a "Jarcho-Levin syndrome" eponym by erstwhile authors, before the introduction of genetic based classification. A literature review showed only three cases of this clinical entity with lipomyelomeningocele. We report the fourth case report of an infant with SCDO with lipomyelomeningocele. His chest X-ray displayed absent left side 6(th)-8(th) ribs with peculiar fan like configuration, making the heart vulnerable to any direct injury. Special care has to be taken for such patients who need surgical procedure in the prone position.

Neural tube defects in Jarcho-Levin syndrome: study of twenty-eight cases

Jarcho-Levin syndrome (JLS) is a congenital disorder consisting of various vertebral and costal anomalies. Congenital heart defects, abdominal wall malformations, urogenital and anal abnormalities, multiple skeletal anomalies, upper limb anomalies, spina bifida, and inguinal, umbilical and diaphragmatic hernias can be seen as components of JLS. Spina bifida appears to be a common finding in reported JLS cases. We retrospectively reviewed the medical records, plain X-rays and MRIs of patients with spina bifida between 2010 and 2014 and discussed the results.

The genetics of common disorders - congenital diaphragmatic hernia

Congenital diaphragmatic hernia (CDH) is a common birth defect with a high mortality and morbidity. Although numerous chromosomal aberrations and gene mutations have been associated with CDH, the etiology of the diaphragmatic defect is identified in less than 50% of patients. This review discusses the some of the more frequent, recurrent karyotypic abnormalities in which CDH is a feature, including 15q26, 8p23.1 and 4p16.3 deletions and tetrasomy 12p (Pallister-Killian syndrome), together with some of the syndromes in which CDH is a relatively common feature, including Fryns syndrome, Matthew-Wood syndrome, overgrowth syndromes and Donnai-Barrow syndrome. In the era of genomic technologies, our knowledge of the genes and chromosome regions involved in pathogenesis of CDH is likely to advance significantly.

Molecular diagnosis of vertebral segmentation disorders in humans

BACKGROUND

Vertebral malformations contribute substantially to the pathophysiology of kyphosis and scoliosis, common health problems associated with back and neck pain, disability, cosmetic disfigurement and functional distress.

OBJECTIVE

To provide an overview of the current understanding of vertebral malformations, at both the clinical level and the molecular level, and factors that contribute to their occurrence.

METHODS

The literature related to the following was reviewed: recent advances in the understanding of the molecular embryology underlying vertebral development and relevance to elucidation of etiologies of several known human vertebral malformation syndromes; outcomes of molecular studies elucidating genetic contributions to congenital and sporadic vertebral malformations; and complex interrelationships between genetic and environmental factors that contribute to the pathogenesis of isolated syndromic and non-syndromic congenital vertebral malformations.

RESULTS/CONCLUSION

Expert opinions extend to discussion of the importance of establishing improved classification systems for vertebral malformation, future directions in molecular and genetic research approaches to vertebral malformation and translational value of research efforts to clinical management and genetic counseling of affected individuals and their families.