Microdeletion on Xq27.1 in a Chinese VACTERL-Like Family with Kidney and Anal Anomalies.

Objective: VATER/VACTERL-like association is associated with adverse pregnancy outcomes. Genetic evidence of this disorder is sporadic. In this study, we aimed to provide genetic insights to improve the diagnosis of VACTERL. Methods: We have described a Chinese family in which four members were affected by renal defects or agenesis, anal atresia, and anovaginal fistula, which is consistent with the diagnosis of a VACTERL-like association. Pedigree and genetic analyses were conducted using genome and exome sequencing. Results: Segregation analysis revealed the presence of a recessive X-linked microdeletion in two living affected individuals, harboring a 196-380 kb microdeletion on Xq27.1, which was identified by familial exome sequencing. Genome sequencing was performed on the affected male, confirming a -196 kb microdeletion in Xq27.1, which included a 28% loss of the CDR-1 gene. Four family members were included in the co-segregation analysis, and only VACTERL-like cases with microdeletions were reported in X27.1. Conclusion: These results suggest that the 196-380 kb microdeletion in Xq27.1 could be a possible cause of the VATER/VACTERL-like association. However, further genetic and functional analyses are required to confirm or rule out genetic background as the definitive cause of the VACTERL association.

VACTERL Association in Patients With Metopic Synostosis: Is There a Link?

VACTERL association is diagnosed based on the non-random co-occurrence of at least 3 out of 6 congenital malformations. The prevalence is thought to be less than 1 in 10,000 to 1 in 40,000. There is no known link between VACTERL association and metopic synostosis in the literature. There were 122 operated cases of metopic synostosis at our institution from 1999 to 2023, with a 2.3:1 male-to-female ratio. The authors describe the co-occurrence of VACTERL association and metopic synostosis in 3 female patients with no identifiable genetic variants. Given that VACTERL association is a diagnosis of exclusion, other rare syndromes were considered but ultimately excluded. This suggests that the co-occurrence of VACTERL association and metopic synostosis is a potentially rare finding, and underlying pathogenic variants are yet to be identified.

Abnormal eyes and spine development in zebrafish (Danio rerio) embryos and larvae induced by triphenyltin.

Triphenyltin (TPT) is widely used in crop pest control and ship antifouling coatings, which leads to its entry into aquatic environment and poses a threat to aquatic organisms. However, the effects of TPT on the early life stages of wild fish in natural water environments remains unclear. The aim of this study was to assess the toxic effects of TPT on the early life stages of fish under two different environments: field investigation and laboratory experiment. The occurrence of deformities in wild fish embryos and larvae in the Three Gorges Reservoir (TGR) and the developmental toxicity of TPT at different concentrations (0, 0.15, 1.5 and 15 µg Sn/L) to zebrafish embryos and larvae were observed. The results showed that TPT content was higher in wild larvae, reaching 27.21 ng Sn/g w, and the malformation of wild fish larvae mainly occurred in the eyes and spine under natural water environment. Controlled experiment exposure of zebrafish larvae to TPT also resulted in eye and spinal deformities. Gene expression analysis showed that compared with the control group, the expression levels of genes related to eye development (sox2, otx2, stra6 and rx1) and spine development (sox9a and bmp2b) were significantly up-regulated in the 15 µg Sn/L exposure group, which may be the main cause of eye and spine deformity in the early development stage of fish. In addition, the molecular docking results further elucidate that the strong hydrophobic and electrostatic interactions between TPT and protein residues are the main mechanism of TPT induced abnormal gene expression. Based on these results, it can be inferred that TPT is one of the teratogenic factors of abnormal eye and spine development in the early life stage of fish in the TGR. These findings have important implications for understanding the toxicity of TPT on fish.

Histology and chronological magnetic resonance images of congenital spinal deformity: An experimental study in mice model.

BACKGROUND: The natural history of the congenital spinal deformity and its clinical magnitude vary widely in human species. However, we previously reported that the spinal deformities of congenital scoliosis mice did not progress throughout our observational period according to soft X-ray and MRI data. In this study, congenital vertebral and intervertebral malformations in mice were assessed via magnetic resonance (MR) and histological images. METHODS: Congenital spinal anomalies were chronologically assessed via soft X-ray and 7 T MR imaging. MR images were compared to the histological images to validate the findings around the malformations. RESULTS: Soft X-ray images showed the gross alignment of the spine and the contour of the malformed vertebrae, with the growth plate and cortical bone visible as higher density lines, but could not be used to distinguish the existence of intervertebral structures. In contrast, MR images could be used to distinguish each structure, including the cortical bone, growth plate, cartilaginous end plate, and nucleus pulposus, by combining the signal changes on T1-weighted imaging (T1WI) and T2-weighted imaging (T2WI). The intervertebral structure adjacent to the malformed vertebrae also exhibited various abnormalities, such as growth plate and cartilaginous end plate irregularities, nucleus pulposus defects, and bone marrow formation. In the chronological observation, the thickness and shape of the malformed structures on T1WI did not change. CONCLUSIONS: Spinal malformations in mice were chronologically observed via 7 T MRI and histology. MR images could be used to distinguish the histological structures of normal and malformed mouse spines. Malformed vertebrae were accompanied by adjacent intervertebral structures that corresponded to the fully segmented structures observed in human congenital scoliosis, but the intervertebral conditions varied. This study suggested the importance of MRI and histological examinations of human congenital scoliosis patients with patterns other than nonsegmenting patterns, which may be used to predict the prognosis of patients with spinal deformities associated with malformed vertebrae.

A regulatory variant impacting TBX1 expression contributes to basicranial morphology in Homo sapiens.

Changes in gene regulatory elements play critical roles in human phenotypic divergence. However, identifying the base-pair changes responsible for the distinctive morphology of Homo sapiens remains challenging. Here, we report a noncoding single-nucleotide polymorphism (SNP), rs41298798, as a potential causal variant contributing to the morphology of the skull base and vertebral structures found in Homo sapiens. Screening for differentially regulated genes between Homo sapiens and extinct relatives revealed 13 candidate genes associated with basicranial development, with TBX1, implicated in DiGeorge syndrome, playing a pivotal role. Epigenetic markers and in silico analyses prioritized rs41298798 within a TBX1 intron for functional validation. CRISPR editing revealed that the 41-base-pair region surrounding rs41298798 modulates gene expression at 22q11.21. The derived allele of rs41298798 acts as an allele-specific enhancer mediated by E2F1, resulting in increased TBX1 expression levels compared to the ancestral allele. Tbx1-knockout mice exhibited skull base and vertebral abnormalities similar to those seen in DiGeorge syndrome. Phenotypic differences associated with TBX1 deficiency are observed between Homo sapiens and Neanderthals (Homo neanderthalensis). In conclusion, the regulatory divergence of TBX1 contributes to the formation of skull base and vertebral structures found in Homo sapiens.

Spinal dysraphism in congenital scoliosis and kyphosis: a retrospective analysis in an Indian population.

PURPOSE: Early recognition is crucial for occult spinal dysraphism associated with congenital spinal deformities. There is limited literature available on its occurrence in congenital scoliosis and kyphosis in the Indian population. METHODS: Our study involved a retrospective review of 247 children who presented at a single centre. We analyzed their demographics and clinical and radiological findings, which included the type of deformity, its location, vertebral anomaly, Cobb angle, and MRI findings. The deformities were categorized as congenital scoliosis or congenital kyphosis with failure of formation, failure of segmentation, or both. RESULTS: A total of 247 cases were examined (congenital scoliosis-229, congenital kyphosis-18). The average age was seven years (range 0.8 to 19 years, SD 4.6). The mean Cobb angle at presentation in the congenital scoliosis group was 49.4° (range 8 to 145°, SD 23.77) for those with abnormal MRI and 42.45° (range 5 to 97°, SD 20.09) for those with normal MRI. For the congenital kyphosis group, the mean K angle at presentation was 47.7° (range 14 to 110°, SD 33.33) for those with abnormal MRI and 47.36° (range 15 to 70°, SD 16.63) for those with normal MRI. Abnormal MRI results were observed in 130 of the patients (congenital scoliosis-53.7%, congenital kyphosis-38.8%). The highest incidence of abnormal MRI findings was observed in the failure of segmentation (66.6%) and mixed (65%) types. Deformities in the dorsal region had the highest incidence (61.9%). The most common dysraphism instances were diastematomyelia and tethered cord. There was a significant correlation between type of deformity and presence of dysraphism. CONCLUSION: This is the largest case series of congenital scoliosis and kyphosis reported from India. We found a high incidence of occult spinal dysraphism as compared to other published series. Occult spinal dysraphism is more common in the thoracic region. Diastematomyelia followed by tethered cord was the most common anomaly observed. We recommend MRI screening of whole spine and craniovertebral junction.

Efficacy and safety of halo-gravity traction in the treatment of spinal deformities: A systematic review of the literature / Eficacia y seguridad de la tracción de halo-gravedad en el tratamiento de las deformidades de columna: una revisión sistemática de la literatura

Objective: To determine, through a systematic review, the effects of halo gravity traction in spinal deformity. Methods: Prospective studies or case series of patients with scoliosis or kyphosis treated with cranial halo gravity traction (HGT) were included. Radiological outcomes were measured in the sagittal and/or coronal planes. Pulmonary function was also assessed. Perioperative complications were also collected. Results: Thirteen studies were included. Congenital etiology was the most frequent etiology observed. Most studies provided clinically relevant curve correction values in the sagittal and coronal planes. Pulmonary values improved significantly after the use of HGT. Finally, there were a pool of 83 complications in 356 patients (23.3%). The most frequent complications were screw infection (38 cases). Conclusions: Preoperative HGT appears to be a safe and effective intervention for deformity that allows correction prior to surgery. However, there is a lack of homogeneity in the published studies.(AU)

Objetivo: Determinar, mediante una revisión sistemática, los efectos de la tracción de halo-gravedad (HGT) en las deformidades de columna. Métodos: Se incluyeron estudios prospectivos o series de casos de pacientes con escoliosis o cifosis tratados con HGT. Los resultados radiológicos se midieron en los planos sagital y/o coronal. También se evaluó la función pulmonar. Finalmente, se recogieron las complicaciones perioperatorias. Resultados: Se incluyeron 13 estudios. La etiología congénita fue la más frecuente. La mayoría de los estudios proporcionaron valores de corrección de la curva clínicamente relevantes en los planos sagital y coronal. Los valores pulmonares mejoraron significativamente tras el uso de HGT. Por último, existieron 83 complicaciones en 356 pacientes, siendo la infección la más frecuente (38 casos). Conclusiones: La HGT mostró ser una intervención segura y eficaz para la deformidad, que permite la corrección antes de la cirugía. Sin embargo, existe una falta de homogeneidad en los estudios publicados.(AU)

[Artículo traducido] Eficacia y seguridad de la tracción de halo-gravedad en el tratamiento de las deformidades de columna: una revisión sistemática de la literatura / Efficacy and safety of halo-gravity traction in the treatment of spinal deformities: A systematic review of the literature

Objective: To determine, through a systematic review, the effects of halo gravity traction in spinal deformity. Methods: Prospective studies or case series of patients with scoliosis or kyphosis treated with cranial halo gravity traction (HGT) were included. Radiological outcomes were measured in the sagittal and/or coronal planes. Pulmonary function was also assessed. Perioperative complications were also collected. Results: Thirteen studies were included. Congenital etiology was the most frequent etiology observed. Most studies provided clinically relevant curve correction values in the sagittal and coronal planes. Pulmonary values improved significantly after the use of HGT. Finally, there were a pool of 83 complications in 356 patients (23.3%). The most frequent complications were screw infection (38 cases). Conclusions: Preoperative HGT appears to be a safe and effective intervention for deformity that allows correction prior to surgery. However, there is a lack of homogeneity in the published studies.(AU)

Objetivo: Determinar, mediante una revisión sistemática, los efectos de la tracción de halo-gravedad (HGT) en las deformidades de columna. Métodos: Se incluyeron estudios prospectivos o series de casos de pacientes con escoliosis o cifosis tratados con HGT. Los resultados radiológicos se midieron en los planos sagital y/o coronal. También se evaluó la función pulmonar. Finalmente, se recogieron las complicaciones perioperatorias. Resultados: Se incluyeron 13 estudios. La etiología congénita fue la más frecuente. La mayoría de los estudios proporcionaron valores de corrección de la curva clínicamente relevantes en los planos sagital y coronal. Los valores pulmonares mejoraron significativamente tras el uso de HGT. Por último, existieron 83 complicaciones en 356 pacientes, siendo la infección la más frecuente (38 casos). Conclusiones: La HGT mostró ser una intervención segura y eficaz para la deformidad, que permite la corrección antes de la cirugía. Sin embargo, existe una falta de homogeneidad en los estudios publicados.(AU)

Core planar cell polarity genes VANGL1 and VANGL2 in predisposition to congenital vertebral malformations.

Congenital scoliosis (CS), affecting approximately 0.5 to 1 in 1,000 live births, is commonly caused by congenital vertebral malformations (CVMs) arising from aberrant somitogenesis or somite differentiation. While Wnt/ß-catenin signaling has been implicated in somite development, the function of Wnt/planar cell polarity (Wnt/PCP) signaling in this process remains unclear. Here, we investigated the role of Vangl1 and Vangl2 in vertebral development and found that their deletion causes vertebral anomalies resembling human CVMs. Analysis of exome sequencing data from multiethnic CS patients revealed a number of rare and deleterious variants in VANGL1 and VANGL2, many of which exhibited loss-of-function and dominant-negative effects. Zebrafish models confirmed the pathogenicity of these variants. Furthermore, we found that Vangl1 knock-in (p.R258H) mice exhibited vertebral malformations in a Vangl gene dose- and environment-dependent manner. Our findings highlight critical roles for PCP signaling in vertebral development and predisposition to CVMs in CS patients, providing insights into the molecular mechanisms underlying this disorder.

Bovine Aortic Arch with an Aberrant Left Vertebral Artery in a 3-Year-Old Boy with VACTERL Association: A Case Report.

BACKGROUND The VACTEREL association is an acronym that includes vertebral malformations (V), anal atresia (A), cardiac defects (C), tracheoesophageal fistula (TE), renal defects (R), and limb malformations (L). The aortic arch is the section between the ascending aorta and the descending aorta, where some variants have been described, such as the right aortic arch and bovine aortic arch, among others. A rare presentation in the Natsis classification is the "type X" where a bovine aortic arch and anomalous origin of the left vertebral artery are present. Several structural cardiac malformations have been described in the VACTEREL association. Still, there is no bovine arch or an anomalous left vertebral artery. CASE REPORT Our patient was a 3-year-old boy with a diagnosis of VACTEREL association (type III esophageal atresia, congenital hip dislocation, scoliosis, bilateral clubfoot, and grade IV biliary ureteral reflux). Echocardiographic findings showed changes in the aortic arch, and angiotomography and magnetic resonance angiography showed a bovine aortic arch and an anomalous left vertebral artery. At the time of diagnosis, there were no clinical manifestations or complications due to the anomalous origin of the left vertebral artery. CONCLUSIONS This is the first description of a bovine type X arch according to the Natsis classification in a VACTEREL association. In general, knowledge of the anatomical variants of the aortic arch and the origin and course of the vertebral arteries is of great clinical and interventional importance, mainly because of the risk of cerebral ischemia.

Association of spinal cord abnormalities with vertebral anomalies: an embryological perspective.

PURPOSE: To analyze the relationship between spinal cord and vertebral abnormalities from the point of view of embryology. METHODS: We analyzed the clinical and radiological data of 260 children with different types of spinal cord malformations in combination with vertebral abnormalities. RESULTS: Among 260 individuals, approximately 109 presented with open neural tube defects (ONTDs), 83 with split cord malformations (SCMs), and 83 with different types of spinal lipomas. Pathological spina bifida emerged as the most frequent vertebral anomaly, affecting 232 patients, with a higher prevalence in ONTD. Vertebral segmentation disorders, including unsegmented bars, butterfly vertebrae, and hemivertebrae, were present in 124 cases, with a higher prevalence in SCM. The third most common spinal anomaly group consisted of various forms of sacral agenesis (58 cases), notably associated with blunt conus medullaris, spinal lipomas, and sacral myelomeningocele. Segmental aplasia of the spinal cord had a typical association with segmental spinal absence (N = 17). CONCLUSION: The association between SCM and neuroenteric cyst/canal and vertebral segmentation disorders is strong. High ONTDs often coincide with pathological spina bifida posterior. Type 1 spinal lipomas and focal spinal nondisjunction also correlate with pathologic spina bifida. Segmental spinal absence or dysgenesis involves localized spinal and spinal cord aplasia, sometimes with secondary filar lipoma.

[Intraosseous cavernous hemangioma of the middle turbinate. Clinical cases]. / Vnutrikostnaya kavernoznaya gemangioma srednei nosovoi rakoviny. Klinicheskie sluchai.

Intraosseous vascular pathology of the turbinates is extremely rare in the practice of an otorhinolaryngologist and can be presented in various histopathological variants. The article presents two clinical cases in which an intraosseous cavernous hemangioma was hidden under the mask of a hypertrophied middle turbinate. The final diagnosis was established by the results of histological examination. The analysis of these clinical cases indicates that, despite the low prevalence, atypical clinical and CT picture, intraosseous formations of the nasal cavity can be of a vascular nature and certainly require a comprehensive examination, including CT, CT with contrast and/or MRI of the nose and paranasal sinuses. These clinical observations indicate that preliminary embolization of feeding vessels before surgical treatment is not required.

Prenatal diagnosis of ROR-2 related Robinow syndrome presenting with fetal ultrasound findings of mesomelia, vertebral, digital and genital abnormalities.

Autosomal recessive ROR2-Robinow syndrome is caused by pathogenic variants in the ROR2 gene. Fetal ultrasound done on our patient at 24 + 3/7 weeks gestation showed macrocephaly, brachycephaly, flat face, prominent forehead, mild frontal bossing, lower thoracic hemivertebrae, digital abnormalities and micropenis. Fetal trio whole exome sequencing done on amniocytes showed two pathogenic compound heterozygous variants in the ROR2 gene, c.1324 C > T; p.(Arg442*) maternally inherited and c.1366dup; p.(Leu456Profs*3) apparently de novo. c.1324 C > T; p.(Arg442*) is a nonsense variant resulting in protein truncation reported to be associated with RRS3. c.1366dup; p.(Leu456Profs*3) is a frameshift variant predicted to result in protein truncation reported to segregate with the disease in multiple affected individuals from a single large family with distal symphalangism of the fourth finger. Fetal autopsy following pregnancy termination showed a large head with low-set ears, facial abnormalities, mesomelic bone shortening, hemivertebra, fused S3 and S4 vertebral bodies, several fused rib heads and short penis with buried shaft.

LUMBAR syndrome-OEIS complex overlap: A case series and review.

We present three new and six published infants with overlapping features of LUMBAR syndrome (lower body hemangioma, urogenital anomalies, spinal cord malformations, bony deformities, anorectal/arterial anomalies and renal anomalies) and OEIS complex (omphalocele, exstrophy, imperforate anus, and spinal defects), also known as cloacal exstrophy. OEIS is included under the recently proposed umbrella coined recurrent constellations of embryonic malformations (RCEMs). The RCEMs represent a phenotypically overlapping spectrum of rare disorders of caudal dysgenesis with unknown cause but likely shared pathogenesis. It has recently been proposed that LUMBAR be considered an RCEM. This report of infants with combined features of OEIS and LUMBAR is the first to demonstrate an overlap between LUMBAR and another RCEM, which supports LUMBAR's inclusion within the RCEM spectrum.

Brain and spine malformations and neurodevelopmental disorders in a cohort of children with CAKUT.

BACKGROUND: Congenital anomalies of the kidney and urinary tract (CAKUT) represent 20-30% of all birth defects and are often associated with extra-renal malformations. We investigated the frequency of brain/spine malformations and neurological features in children with CAKUT. METHODS: We reviewed the clinico-radiological and genetic data of 199 out of 1,165 children with CAKUT evaluated from 2006 to 2023 (99 males, mean age at MRI 6.4 years) who underwent brain and/or spine MRI. Patients were grouped according to the type of CAKUT (CAKUT-K involving the kidney and CAKUT-H involving the inferior urinary tract). Group comparisons were performed using χ2 and Fisher exact tests. RESULTS: Brain/spine malformations were observed in 101/199 subjects (50.7%), 8.6% (101/1165) of our CAKUT population, including midbrain-hindbrain anomalies (40/158, 25.3%), commissural malformations (36/158, 22.7%), malformation of cortical development (23/158, 14.5%), Chiari I anomaly (12/199, 6%), cranio-cervical junction malformations (12/199, 6%), vertebral defects (46/94, 48.9%), caudal regression syndrome (29/94, 30.8%), and other spinal dysraphisms (13/94, 13.8%). Brain/spine malformations were more frequent in the CAKUT-K group (62.4%, p < 0.001). Sixty-two subjects (62/199, 31.2%) had developmental delay/intellectual disability. Neurological examination was abnormal in 40/199 (20.1%). Seizures and/or electroencephalographic anomalies were reported in 28/199 (14%) and behavior problems in 19/199 subjects (9%). Developmental delay/intellectual disability was more frequent in kidney dysplasia (65.2%) and agenesis (40.7%) (p = 0.001). CONCLUSIONS: We report a relative high frequency of brain/spine malformations and neurodevelopmental disorders in children with CAKUT who underwent MRI examinations in a tertiary referral center, widening the spectrum of anomalies associated with this condition.

A rare skeletal dysplasia in the etiology of severe scoliosis: Diaphanospondylodysostosis.

Diaphanospondylodysostosis is a rare genetic skeletal disorder caused by biallelic variants in the BMPER gene. The term, diaphanospondylodysostosis, includes ischiospinal dysotosis, which was previously known as a distinct entity with milder clinical features. The clinical phenotype of diaphanospondylodysostosis is quite variable with mortality in early postnatal life in some patients. Main clinical and radiographic features are narrow thorax, vertebral segmentation defects, rib anomalies, ossification defects of vertebrae, ischium and sacrum, and renal cysts. In this study, we report on a 14-year-old girl patient with diaphanospondylodysostosis harbouring a novel BMPER mutation. The patient presented with severe scoliosis and severely hypoplastic/aplastic distal phalanges of the fingers and toes, findings yet hitherto not described in this syndrome.

Longitudinal skeletal growth and growth plate morphological characteristics of chondro-tissue specific CUL7 knockout mice.

BACKGROUND: 3 M syndrome is first reported in 1975，which characterized by severe pre- and postnatal growth retardation, skeletal malformation and facial dysmorphism. These three genes (CUL7, OBSL1 and CCDC8) have been identified to be respond for 3 M syndrome, of which CUL7 is accounting for approximately 70%. To date, the molecular mechanism underlying the pathogenesis of 3 M syndrome remains poorly understood. Previous studies showed that no Cul7-/- mice could survive after birth, because of growth retardation at late gestational stage and respiratory distress after birth. The establishment of the animal model of cartilage specific Cul7 knockout mice (Cul7fl/fl;Col2a1-CreERT2 mice) has confirmed that Cul7fl/fl;Col2a1-CreERT2 mice can be selective in a time- and tissue-dependent manner, which can provide an experimental basis for further research on severe genetic diseases related to growth plates. OBJECTIVE: To establish a model of Cul7fl/fl;Col2a1-CreERT2 mice based on Cre/LoxP system, and to further observe its phenotype and morphological changes in growth plate. METHODS: The Cul7fl/fl;Col2a1-CreERT2 mice were taken as the experimental group, while the genotype of Cul7fl/+;Col2a1-CreERT2 mice were used as the control group. The gross morphological features and X-ray films of limbs in the two groups were observed every week for 3-6 consecutive weeks, and the length of the mice from nose to the tail, the length of femur and tibia were recorded. In the meantime, The histological morphology of tibial growth plates was compared between the two groups. RESULTS: A preliminary model of Cul7fl/fl;Col2a1-CreERT2 mice was established. The Cul7fl/fl;Col2a1-CreERT2 mice had abnormally short and deformed limbs (P<0.05), increased thickness of growth plate, the disorderly arranged chondrocyte columns, decreased number of cells in the proliferation zone, changes in the shape from flat to round, obviously expanded extracellular matrix, and disordered arrangement, thickening and loosening of bone trabecula at the proximal metaphysis of the femur. CONCLUSIONS: The knockout of Cul7 gene may affect both the proliferation of chondrocytes and the endochondral osteogenesis, confirming that Cul7 is essential for the normal development of bone in the body.

Unraveling the genetic architecture of congenital vertebral malformation with reference to the developing spine.

Congenital vertebral malformation, affecting 0.13-0.50 per 1000 live births, has an immense locus heterogeneity and complex genetic architecture. In this study, we analyze exome/genome sequencing data from 873 probands with congenital vertebral malformation and 3794 control individuals. Clinical interpretation identifies Mendelian etiologies in 12.0% of the probands and reveals a muscle-related disease mechanism. Gene-based burden test of ultra-rare variants identifies risk genes with large effect sizes (ITPR2, TBX6, TPO, H6PD, and SEC24B). To further investigate the biological relevance of the genetic association signals, we perform single-nucleus RNAseq on human embryonic spines. The burden test signals are enriched in the notochord at early developmental stages and myoblast/myocytes at late stages, highlighting their critical roles in the developing spine. Our work provides insights into the developmental biology of the human spine and the pathogenesis of spine malformation.

Instrumentation failure following pediatric spine deformity growth-sparing surgery using traditional growing rods or vertical expandable prosthetic titanium ribs.

BACKGROUND: Instrumentation failure (IF) is a major complication associated with growth-sparing surgery for pediatric spinal deformities; however, studies focusing on IF following each surgical procedure are lacking. We aimed to evaluate the incidence, timing, and rates of unplanned return to the operating room (UPROR) associated with IF following each surgical procedure in growth-sparing surgeries using traditional growing rods (TGRs) and vertical expandable prosthetic titanium ribs (VEPTRs). METHODS: We reviewed 1,139 surgical procedures documented in a Japanese multicenter database from 2015 to 2017. Of these, 544 TGR and 455 VEPTR procedures were included for evaluation on a per-surgery basis. IF was defined as the occurrence of an implant-related complication requiring revision surgery. RESULTS: The surgery-based incidences of IF requiring revision surgery in the TGR and VEPTR groups were 4.3% and 4.0%, respectively, with no significant intergroup difference. Remarkably, there was a negative correlation between IF incidence per surgical procedure and the number of lengthening surgeries in both groups. In addition, rod breakage in the TGR group and anchor-related complications in the VEPTR group tended to occur relatively early in the treatment course. The surgery-based rates of UPROR due to IF in the TGR and VEPTR groups were 2.0% and 1.5%, respectively, showing no statistically significant difference. CONCLUSIONS: We found that IF, such as anchor related-complications and rod breakage, occurs more frequently earlier in the course of lengthening surgeries. This finding may help in patient counseling and highlights the importance of close postoperative follow-up to detect IF and improve outcomes.