Genetic insights into the 'sandwich fusion' subtype of Klippel-Feil syndrome: novel FGFR2 mutations identified by 21 cases of whole-exome sequencing.

BACKGROUND: Klippel-Feil syndrome (KFS) is a rare congenital disorder characterized by the fusion of two or more cervical vertebrae during early prenatal development. This fusion results from a failure of segmentation during the first trimester. Although six genes have previously been associated with KFS, they account for only a small proportion of cases. Among the distinct subtypes of KFS, "sandwich fusion" involving concurrent fusion of C0-1 and C2-3 vertebrae is particularly noteworthy due to its heightened risk for atlantoaxial dislocation. In this study, we aimed to investigate novel candidate mutations in patients with "sandwich fusion." METHODS: We collected and analyzed clinical data from 21 patients diagnosed with "sandwich fusion." Whole-exome sequencing (WES) was performed, followed by rigorous bioinformatics analyses. Our focus was on the six known KFS-related genes (GDF3, GDF6, MEOX1, PAX1, RIPPLY2, and MYO18). Suspicious mutations were subsequently validated through in vitro experiments. RESULTS: Our investigation revealed two novel exonic mutations in the FGFR2 gene, which had not previously been associated with KFS. Notably, the c.1750A > G variant in Exon 13 of FGFR2 was situated within the tyrosine kinase domain of the protein, in close proximity to several established post-translational modification sites. In vitro experiments demonstrated that this certain mutation significantly impacted the function of FGFR2. Furthermore, we identified four heterozygous candidate variants in two genes (PAX1 and MYO18B) in two patients, with three of these variants predicted to have potential clinical significance directly linked to KFS. CONCLUSIONS: This study encompassed the largest cohort of patients with the unique "sandwich fusion" subtype of KFS and employed WES to explore candidate mutations associated with this condition. Our findings unveiled novel variants in PAX1, MYO18B, and FGFR2 as potential risk mutations specific to this subtype of KFS.

Tetraparesis following thoracic spine surgery in a patient with Klippel-Feil syndrome and ABCB4 mutation: a case report.

BACKGROUND: Klippel-Feil syndrome is a rare condition described in 1912 by Maurice Klippel and André Feil. It is defined as a congenital cervical fusion of at least two vertebrae, associated with a classical triad of clinical signs: short neck, low posterior hairline, and limited range of movement. However, Klippel-Feil syndrome manifests with a vast spectrum of phenotypes, ranging from no symptoms to complete triad, with or without other associated malformations. Most commonly, CCF results from sporadic mutations, even though autosomal recessive, autosomal dominant, or even X-linked inheritance can be detected. The ATP-binding cassette subfamily B member 4 is only expressed in the liver and is involved in biliary phospholipid secretion. The clinical spectrum includes various hepatobiliary pathologies, including low phospholipid-associated cholelithiasis, and has never been associated with musculoskeletal anomalies. CASE PRESENTATION: A 55-year-old male Caucasian patient presenting with low phospholipid-associated cholelithiasis syndrome with ATP-binding cassette subfamily B member 4 mutation and liver cirrhosis was referred to our clinic for a liver transplant. A period of 6 months before, the patient underwent a T7-T9 posterior fixation for a T8 osteoporotic fracture. Postoperatively, he was tetraparetic, whereas he was neurologically intact before the operation. At admission to our hospital, he was still tetraparetic and presented with clinical signs of cervical myelopathy. Moreover, he suffered a limitation of cervical range of motion in all directions, short neck, and low posterior hairline. Imaging showed multiple cervical and thoracic vertebral bodies fusion, as well as cervical spine stenosis. Based on the available data, we diagnosed a type 3 Klippel-Feil syndrome according to Samartzis' classification. CONCLUSIONS: The heterogeneity of KFS and the various potential hereditary links that are known indicate that it is important to highlight all potential cases related to known genetic defects. At present, no association between ATP-binding cassette subfamily B member 4 mutation and congenital cervical fusions has been reported. The other important clinical focus of this case is the appearance of spontaneous tetraparesis after thoracic spine surgery. This mechanism remains unclear, but considering different spinal anatomy it might have been due to difficult intubation and patient's positioning during his previous operation.

Detailed clinical and radiological features of the first patient with Elsahy-Waters syndrome in East Asia.

Elsahy-Waters syndrome (EWS; OMIM#211380) is a rare autosomal recessive disorder that is caused by loss-of-function variants in CDH11, which encodes cadherin 11. EWS is characterized by brachycephaly, midface hypoplasia, characteristic craniofacial morphology, cervical fusion, cutaneous syndactyly in 2-3 digits, genitourinary anomalies, and intellectual disability. To the best of our knowledge, there have been only six patients of molecularly confirmed EWS. We report the first patient of EWS in East Asia in a Japanese man with a novel splice site homozygous variant of CDH11. We reviewed the clinical and molecular findings in previously reported individuals and the present patient. In addition to the previously reported clinical features of EWS, the present patient had unreported findings of atlantoaxial instability due to posterior displacement of dens, thoracic fusion, thoracic butterfly vertebra, sacralization of the lumbar vertebra (L5), and multiple perineural cysts. The spinal findings in this patient could represent a new spectrum of skeletal phenotypes of EWS. It remains to be clarified whether the multiple perineural cysts in the patient were associated with EWS or coincidental. The current observation might contribute to an expanded understanding of the clinical consequences of loss-of-function of cadherin 11.

Klippel-Feil Syndrome: Pathogenesis, Diagnosis, and Management.

Klippel-Feil syndrome (KFS), or congenital fusion of the cervical vertebrae, has been thought to be an extremely rare diagnosis. However, recent literature suggests an increased prevalence, with a high proportion of asymptomatic individuals. Occurring as a sporadic mutation or associated with several genes, the pathogenesis involves failure of cervical somite segmentation and differentiation during embryogenesis. Most commonly, the C2-C3 and C5-C6 levels are involved. KFS is associated with other orthopaedic conditions including Sprengel deformity, congenital scoliosis, and cervical spine abnormalities, as well as several visceral pathologies. There are several classification systems, some based on the anatomic levels of fusion and others on its genetic inheritance. Management of patients with KFS primarily involves observation for asymptomatic individuals. Surgical treatment may be for neurologic complaints, correction of deformity, concomitant spinal anomalies, or for associated conditions and varies significantly. Participation in sports is an important consideration. Recommendations for contact sports or activities depend on both the level and the number of vertebrae involved in the fusion. A multidisciplinary team should be involved in the treatment plan and recommendations for complex presentations.

Rare association of Klippel-Feil syndrome with situs inversus totalis and review of the genetic background.

Klippel-Feil syndrome (KFS) is a rare congenital anomaly in forming the cervical vertebrae resulting in the fusion of two or more of the vertebrae. KFS is associated with many congenital anomalies, some of which are common and well known. Here, we report a child with an extremely rare association of KFS with situs inversus totalis (SIT). Both KFS and SIT are genetically heterogeneous and their co-occurrence suggests a high possibility of sharing the same underlying causative agent. Here, we review the genetic background that is known for these two conditions in the literature.

The VANGL1 P384R variant cause both neural tube defect and Klippel-Feil syndrome.

BACKGROUND: Neural tube defect (NTD) is a common birth defect causing much death in the world. Variants in VANGL1 lead to NTD and caudal regression syndrome. NTD displays a complex phenotype encompassing both genetic and environmental factors. METHODS: The fetus was diagnosed by prenatal ultrasound examination. Postnatal CT and autopsy were performed. Genetic testing was conducted in the family and Sanger sequencing was validated. Multiple prediction soft-wares were used to predict the pathogenicity of the variant. RESULTS: The VANGL1 gene variant c.1151C>G (P384R) was detected in a fetus diagnosed with tethered spinal cord and sacrococcygeal lipoma. The VANGL1 variant c.1151C>G (P384R) was reported in a Klippel-Feil syndrome patient. The VANGL1 variant was validated in the trio-family but the mother showed no abnormalities. CONCLUSION: Overall, this study presents fetal NTD caused by the same VANGL1 variant found in a Klippel-Feil syndrome patient with complete clinical information of prenatal ultrasound, postnatal CT, and genetic results as early as 25 GW. Our study not only expands the VANGL1 mutational spectrum but also sheds light on the important role of the VANGL1 P384R variant in human development.

[Clinical Characteristics and Genetic Analysis of Klippel-Feil Syndrome].

Objective To summarize clinical characteristics and investigate possible pathogenic gene of Klippel-Feil syndrome(KFS)by the self-designed multigene panel sequencing,so as to decipher the molecular basis for early diagnosis and targeted therapy.Methods From January 2015 to December 2018,we consecutively recruited 25 patients who were diagnosed with KFS in Peking Union Medical College Hospital.The demographic information,clinical manifestations,physical examination and radiological assessments were analyzed.Multigene panel sequencing was performed after DNA extraction from peripheral blood.The possible pathogenic mutations of KFS were explored on the basis of bioinformatics analysis.Results The KFS cohort consisted of 25 patients,including 15 males and 10 females,with a mean age of(12.9±7.3)years.Limited cervical range of motion was the most common clinical feature(12 cases,48%).Based on the Samartzis classification,the proportion of patients suffered from short neck(P=0.031)and limited cervical range of motion(P=0.026)in type Ⅲ KFS was significantly higher than that in type Ⅱ and type Ⅰ KFS.Panel sequencing detected a total of 11 pathogenic missense mutations in eight patients,including COL6A1,COL6A2,CDAN1,GLI3,FLNB,CHRNG,MYH3,POR,and TNXB.There was no pathogenic mutation found in five reported pathogenic genes(GDF6,MEOX1,GDF3,MYO18B and RIPPLY2)associated with KFS.Conclusions Our study has shown that patients with multiple contiguous cervical fusions are more likely to manifest short neck,limited cervical range of motion,and clinical triad.Therefore,these patients need additional attention and follow-up.Our analysis highlights novel KFS-related genetic variants,such as COL6A and CDAN1,extending the spectrum of known mutations contributing to this syndrome and providing a basis for elucidating the pathogenesis of KFS.

Further delineation of MYO18B-related autosomal recessive Klippel-Feil syndrome with myopathy and facial dysmorphism.

Klippel-Feil syndrome 4 (KFS4; MIM# 616549) is an autosomal recessive disorder caused by biallelic pathogenic variants in MYO18B and comprises, in addition to Klippel-Feil anomaly (KFA), nemaline myopathy, facial dysmorphism, and short stature. We aim to outline the natural history of KFS4 and provide an updated description of its clinical, radiological, laboratory, and molecular findings. We comprehensively analyzed the medical records of 6 Saudi and 1 American patients (including 5 previously unpublished cases) with a molecularly confirmed diagnosis of KFS4. All patients had myopathy of varying severity that followed a slowly progressive or non-progressive course, affecting primarily the proximal musculature of the lower limb although hand involvement with distal arthrogryposis and abnormal interphalangeal creases was also observed. KFA and characteristic dysmorphic features, including ptosis and bulbous nose, were observed in all but two patients. The causal MYO18B variants were a founder NM_032608.5:c.6905C>A; p.(Ser2302*) variant in the Saudi patients (P1-P6) and a novel MYO18B homozygous variant (c.6660_6670del;p.[Arg2220Serfs*74]) in the American Caucasian patient (P7). We report the phenotypic and genetic findings in seven patients with KFS4. We describe the natural history of this disease, confirm myopathy as a universal feature and describe its pattern and progression, and note interesting differences between the phenotypes observed in patients with KFA and those without.

Clinical Characteristics and Genetic Analysis of Klippel-Feil Syndrome / 中国医学科学院学报

Objective To summarize clinical characteristics and investigate possible pathogenic gene of Klippel-Feil syndrome(KFS)by the self-designed multigene panel sequencing,so as to decipher the molecular basis for early diagnosis and targeted therapy.Methods From January 2015 to December 2018,we consecutively recruited 25 patients who were diagnosed with KFS in Peking Union Medical College Hospital.The demographic information,clinical manifestations,physical examination and radiological assessments were analyzed.Multigene panel sequencing was performed after DNA extraction from peripheral blood.The possible pathogenic mutations of KFS were explored on the basis of bioinformatics analysis.Results The KFS cohort consisted of 25 patients,including 15 males and 10 females,with a mean age of(12.9±7.3)years.Limited cervical range of motion was the most common clinical feature(12 cases,48%).Based on the Samartzis classification,the proportion of patients suffered from short neck(P=0.031)and limited cervical range of motion(P=0.026)in type Ⅲ KFS was significantly higher than that in type Ⅱ and type Ⅰ KFS.Panel sequencing detected a total of 11 pathogenic missense mutations in eight patients,including COL6A1,COL6A2,CDAN1,GLI3,FLNB,CHRNG,MYH3,POR,and TNXB.There was no pathogenic mutation found in five reported pathogenic genes(GDF6,MEOX1,GDF3,MYO18B and RIPPLY2)associated with KFS.Conclusions Our study has shown that patients with multiple contiguous cervical fusions are more likely to manifest short neck,limited cervical range of motion,and clinical triad.Therefore,these patients need additional attention and follow-up.Our analysis highlights novel KFS-related genetic variants,such as COL6A and CDAN1,extending the spectrum of known mutations contributing to this syndrome and providing a basis for elucidating the pathogenesis of KFS.

GDF6-CD99 Signaling Regulates Src and Ewing Sarcoma Growth.

We report here that the autocrine signaling mediated by growth and differentiation factor 6 (GDF6), a member of the bone morphogenetic protein (BMP) family of cytokines, maintains Ewing sarcoma growth by preventing Src hyperactivation. Surprisingly, Ewing sarcoma depends on the prodomain, not the BMP domain, of GDF6. We demonstrate that the GDF6 prodomain is a ligand for CD99, a transmembrane protein that has been widely used as a marker of Ewing sarcoma. The binding of the GDF6 prodomain to the CD99 extracellular domain results in recruitment of CSK (C-terminal Src kinase) to the YQKKK motif in the intracellular domain of CD99, inhibiting Src activity. GDF6 silencing causes hyperactivation of Src and p21-dependent growth arrest. We demonstrate that two GDF6 prodomain mutants linked to Klippel-Feil syndrome are hyperactive in CD99-Src signaling. These results reveal a cytokine signaling pathway that regulates the CSK-Src axis and cancer cell proliferation and suggest the gain-of-function activity for disease-causing GDF6 mutants.

The mutational burden and oligogenic inheritance in Klippel-Feil syndrome.

BACKGROUND: Klippel-Feil syndrome (KFS) represents a rare anomaly characterized by congenital fusion of the cervical vertebrae. The underlying molecular etiology remains largely unknown because of the genetic and phenotypic heterogeneity. METHODS: We consecutively recruited a Chinese cohort of 37 patients with KFS. The clinical manifestations and radiological assessments were analyzed and whole-exome sequencing (WES) was performed. Additionally, rare variants in KFS cases and controls were compared using genetic burden analysis. RESULTS: We primarily examined rare variants in five reported genes (GDF6, MEOX1, GDF3, MYO18B and RIPPLY2) associated with KFS and detected three variants of uncertain significance in MYO18B. Based on rare variant burden analysis of 96 candidate genes related to vertebral segmentation defects, we identified BAZ1B as having the highest probability of association with KFS, followed by FREM2, SUFU, VANGL1 and KMT2D. In addition, seven patients were proposed to show potential oligogenic inheritance involving more than one variants in candidate genes, the frequency of which was significantly higher than that in the in-house controls. CONCLUSIONS: Our study presents an exome-sequenced cohort and identifies five novel genes potentially associated with KFS, extending the spectrum of known mutations contributing to this syndrome. Furthermore, the genetic burden analysis provides further evidence for potential oligogenic inheritance of KFS.

Congenital posterior cervical spine malformation due to biallelic c.240-4T>G RIPPLY2 variant: A discrete entity.

The clinical and radiological spectrum of spondylocostal dysostosis syndromes encompasses distinctive costo-vertebral anomalies. RIPPLY2 biallelic pathogenic variants were described in two distinct cervical spine malformation syndromes: Klippel-Feil syndrome and posterior cervical spine malformation. RIPPLY2 is involved in the determination of rostro-caudal polarity and somite patterning during development. To date, only four cases have been reported. The current report aims at further delineating the posterior malformation in three new patients. Three patients from two unrelated families underwent clinical and radiological examination through X-ray, 3D computed tomography and brain magnetic resonance imaging. After informed consent was obtained, family-based whole exome sequencing (WES) was performed. Complex vertebral segmentation defects in the cervico-thoracic spine were observed in all patients. WES led to the identification of the homozygous splicing variant c.240-4T>G in all subjects. This variant is predicted to result in aberrant splicing of Exon 4. The current report highlights a subtype of cervical spine malformation with major atlo-axoidal malformation compromising spinal cord integrity. This distinctive mutation-specific pattern of malformation differs from Klippel-Feil syndrome and broadens the current classification, defining a sub-type of RIPPLY2-related skeletal disorder. Of note, the phenotype of one patient overlaps with oculo-auriculo-vertebral spectrum disorder.

A novel pathogenic variant in MYO18B associating early-onset muscular hypotonia, and characteristic dysmorphic features, delineation of the phenotypic spectrum of MYO18B-related conditions.

Homozygous loss-of-function variants in MYO18B have been associated with congenital myopathy, facial dysmorphism and Klippel-Feil anomaly. So far, only four patients have been reported. Comprehensive description of new cases that help to highlight recurrent features and to further delineate the phenotypic spectrum are still missing. We present the fifth case of MYO18B-associated disease in a newborn male patient. Trio exome sequencing identified the previously unreported homozygous nonsense variant c.6433C>T, p.(Arg2145*) in MYO18B (NM_032608.5). While most phenotypic features of our patient align with previously reported cases, we describe the prenatal features for the first time. Taking the phenotypic description of our patient into account, we propose that the core phenotype comprises a severe congenital myopathy with feeding difficulties in infancy and characteristic dysmorphic features.

Klippel-Feil syndrome: a review of the literature.

Klippel-Feil syndrome is a congenital defect in the formation or segmentation of the cervical spine. A wide spectrum of associated anomalies may be present. This heterogeneity has complicated clarification of the genetic causes and management of patient's with congenital vertebral fusion. In this review, we focussed on clinical heterogeneity; radiographic abnormalities and genetic etiology in Klippel-Feil syndrome. We insist on comprehensive evaluation and delineation of diagnostic and prognostic classes.

Klippel-Feil syndrome misdiagnosed as spondyloarthropathy: case-based review.

Spondyloarthropathy refers to any joint disease of the vertebral column, but the term is mainly used for a specific group of disorders called seronegative spondyloarthropathies (SpAs). The axial skeletal involvement, peripheral and extra-articular manifestations and an association with the major histocompatibility complex class I human leukocyte antigen-B27 (HLA B27) are commonly shared features of SpAs. Klippel-Feil syndrome (KFS) is a rare congenital disorder characterized by the fusion of one or more cervical vertebrae, accompanied by various skeletal and extra-skeletal anomalies. We report a case of an adult male patient with HLA B27 positivity presenting with chronic cervical spine pain accompanied by morning stiffness and periodic night pain, with radiologically confirmed ankylosis and fusion of several cervical segments. His medical history included urogenital abnormalities operated in childhood and mild mitral prolapse. Initially suspected diagnosis of an early axial form of SpA was rejected after thorough workup. Instead, the nature of vertebral defects along with the past medical history of urogenital and cardiac abnormalities pointed towards the diagnosis of KFS. HLA B27 presence can be a confounder in patients presenting with spinal pain and that is why the differential diagnosis of CSD-s and SpA can be challenging in some patients.

Expanding the clinical history associated with syndromic Klippel-Feil: A unique case of comorbidity with medulloblastoma.

Klippel-Feil syndrome (KFS) is an exceedingly rare constitutional disorder in which a paucity of knowledge exists about the disease and its associated morbidity and mortality. We present a 4-year-old male with KFS, who notably was also diagnosed with large-cell anaplastic medulloblastoma. We evaluated the genetic basis of co-occurring KFS and medulloblastoma and the role of MYO18B as related to medulloblastoma. Constitutional and somatic variant and copy number analyses were performed from DNA-based exome studies, along with RNA-sequencing of tumor tissue, to elucidate the genetic etiology of the co-existing disease states. We identified novel constitutional compound heterozygous frameshift variants (NM_032608.5: p.Leu2257SerfsTer16 and p.Arg2220SerfsTer74) each encoding a premature stop of translation in MYO18B, consistent with a diagnosis of KFS. We did not identify any somatic variants of known relevance or disease-relevant therapeutic targets in the tumor. The somatic copy number profile was suggestive of Group 3γ medulloblastoma. Relative to pediatric brain tumors, medulloblastoma, particularly, Group 3, had increased gene expression of MYO18B. In summary, coexisting constitutional and somatic diagnoses in this patient enabled the elucidation of the genetic etiology of KFS and provided support for the role of MYO18B in tumor suppression.

Síndrome de Klippel-Feil: a propósito de un caso en Ecuador / Klippel-Feil syndrome: about a case in Ecuador

El síndrome de Klippel-Feil (KFS) es un grupo heterogéneo de malformaciones a nivel vertebral que presentan un componente genético monogénico; se caracteriza por presentar un defecto en la formación o segmentación de las vértebras cervicales, que da como resultado una apariencia fusionada. La tríada clínica consiste en un cuello corto, una línea de implantación baja del cabello y un movimiento limitado del cuello. Presentamos el caso de un paciente masculino de 17 años que manifiesta los hallazgos clínicos y radiológicos de esta anomalía. (AU)

Klippel-Feil syndrome (KFS) is a heterogeneous group of vertebral malformations that presents a monogenic genetic component, characterized by a defect in the formation or segmentation of the cervical vertebrae, which results in a fused appearance. The clinical triad consists of a short neck, a low hairline and a limited movement of the neck. We present the case of a 17 year-old male patient who presented the clinical and radiological findings of this anomaly. (AU)

Skeletal malformations of Meox1-deficient zebrafish resemble human Klippel-Feil syndrome.

Klippel-Feil syndrome is a congenital vertebral anomaly, which is characterised by the fusion of at least two cervical vertebrae and a clinically broad set of symptoms, including congenital scoliosis and elevated scapula (Sprengel's deformity). Klippel-Feil syndrome is associated with mutations in MEOX1. The zebrafish mutant choker (cho) carries a mutation in its orthologue, meox1. Although zebrafish is being increasingly employed as fidelitous models of human spinal disease, the vertebral column of Meox1-deficient fish has not been assessed for defects. Here, we describe the skeletal defects of meox1cho mutant zebrafish utilising alizarin red to stain bones and chemical maceration of soft tissue to detect fusions in an unbiased manner. Obtained data reveal that meox1cho mutants feature aspects of a number of described symptoms of patients who suffer from Klippel-Feil syndrome and have mutations in MEOX1. These include vertebral fusion, congenital scoliosis and an asymmetry of the pectoral girdle, which resembles Sprengel's deformity. Thus, the meox1cho mutant zebrafish may serve as a useful tool to study the pathogenesis of the symptoms associated with Klippel-Feil syndrome.

An MRspec database query and visualization engine with applications as a clinical diagnostic and research tool.

PURPOSE: Proton magnetic resonance spectroscopy (MRspec), one of the very few techniques for in vivo assessment of neuro-metabolic profiles, is often complicated by lack of standard population norms and paucity of computational tools. METHODS: 7035 scans and clinical information from 4430 pediatric patients were collected from 2008 to 2014. Scans were conducted using a 1.5T (n=3664) or 3T scanner (n=3371), and with either a long (144ms, n=5559) or short echo time (35ms, n=1476). 3055 of these scans were localized in the basal ganglia (BG), 1211 in parieto-occipital white matter (WM). 34 metabolites were quantified using LCModel. A web application using MySQL, Python and Flask was developed to facilitate the exploration of the data set. RESULTS: Already piloting the application revealed numerous insights. (1), N-acetylaspartate (NAA) increased throughout all ages. During early infancy, total choline was highly varied and myo-inositol demonstrated a downward trend. (2), Total creatine (tCr) and creatine increased throughout childhood and adolescence, though phosphocreatine (PCr) remained constant beyond 200days. (3), tCr was higher in BG than WM. (4), No obvious gender-related differences were observed. (5), Field strength affects quantification using LCModel for some metabolites, most prominently for tCr and total NAA. (6), Outlier analysis identified patients treated with vigabatrin through elevated γ-aminobutyrate, and patients with Klippel-Feil syndrome, Leigh disease and L2-hydroxyglutaric aciduria through low choline in BG. CONCLUSIONS: We have established the largest MRSpec database and developed a robust and flexible computational tool for facilitating the exploration of vast metabolite datasets that proved its value for discovering neurochemical trends for clinical diagnosis, treatment monitoring, and research. Open access will lead to its widespread use, improving the diagnostic yield and contributing to better understanding of metabolic processes and conditions in the brain.

Disordered vertebral and rib morphology in pudgy mice. Structural relationships to human scoliosis.

Normal and abnormal vertebral development have been studied over the past 200 years at increasing levels of resolution as techniques for biological investigation have improved. Disordered development of the axial skeleton from the early embryonic period on leads to structurally malformed vertebrae and intervertebral discs and ribs causing the severe deformities of scoliosis, kyphosis, and kyphoscoliosis. Developmental malformation of the axial skeleton therefore has led to considerable biological and clinical interest. This work will detail our studies on the structural deformities of the vertebral column and adjacent ribs in the pudgy mouse [1] caused by mutations in the delta-like 3 (Dll3) gene of the Notch family [2]. While gene abnormalities in the pudgy mouse have been outlined, there has been no in-depth assessment of the histopathology of the pudgy vertebral and rib abnormalities that this study will provide. In addition, although congenital scoliosis has been recognized as a clinical problem since the mid-nineteenth century (1800s) [3] and accurately defined by radiography since the early twentieth century (1900s) [4-6], there have been few detailed histopathologic studies of human cases. We will also relate our histopathologic findings in the pudgy mouse to the histopathology of human vertebral and rib malformations in clinical cases of congenital scoliosis, one of which we defined in detail previously [7].