Congenital vertebral malformations (CVMs), affecting approximately 0.5-1 per 1000 live births, occur either in an isolated form or as part of syndromic disorders. Despite the identification of numerous causative genes for CVMs, the molecular etiology of most cases remains unknown. In this study, we applied a three-tiered diagnostic approach (chromosomal microarray analysis, followed by custom gene panel analysis, and exome/genome sequencing) in a cohort of 34 patients with CVMs. We achieved a 12% diagnostic success rate, identifying a deletion upstream of SOX9 and pathogenic or likely pathogenic variants in FLNB and KMT2D. Most pathogenic variants were detected by exome or genome sequencing, while earlier-tier analyses yielded limited results. We also identified two candidate genes, NSD2 and TBXT, that may contribute to the phenotype observed in our patients, but warrant future functional validation. Our work expands the molecular spectrum of CVMs and highlights the utility of comprehensive genomic testing for improving diagnosis and understanding of vertebral development disorders.

Klippel-Feil syndrome (KFS) is a rare congenital disorder characterized by the fusion of cervical vertebrae, with a clinical presentation that can vary widely due to genetic and phenotypic diversity. While KFS can occur as an isolated anomaly, it is often associated with other congenital conditions, such as Sprengel deformity, which may present with or without an omovertebral bone, complicating diagnosis and management. This particular case also involves diffuse large B-cell lymphoma (DLBCL), the most common subtype of non-Hodgkin lymphoma. We hereby present a complex case of a 60-year-old male with the co-occurrence of KFS, Sprengel deformity, and DLBCL. Diagnostic imaging revealed an ill-defined right neck mass on ultrasound which was confirmed on neck CT. The CT also demonstrated an elevated left scapula and a left omovertebral bone, indicative of Sprengel deformity. There was fusion of the C5 and C6 vertebrae consistent with KFS. A whole-body F-18 FDG PET scan demonstrated significant uptake in the neck mass, leading to a biopsy that confirmed DLBCL. This case highlights the importance of comprehensive medical and imaging evaluations in diagnosing and managing the complexities associated with these disorders. In particular, awareness of the potential co-existence of congenital abnormalities and aggressive malignancies is critical in such cases.

Vertebral malformations (VMs) pose a significant global health problem, causing chronic pain and disability. Vertebral defects occur as isolated conditions or within the spectrum of various congenital disorders, such as Klippel-Feil syndrome, congenital scoliosis, spondylocostal dysostosis, sacral agenesis, and neural tube defects. Although both genetic abnormalities and environmental factors can contribute to abnormal vertebral development, our knowledge on molecular mechanisms of numerous VMs is still limited. Furthermore, there is a lack of resource that consolidates the current knowledge in this field. In this pioneering review, we provide a comprehensive analysis of the latest research on the molecular basis of VMs and the association of the VMs-related causative genes with bone developmental signaling pathways. Our study identifies 118 genes linked to VMs, with 98 genes involved in biological pathways crucial for the formation of the vertebral column. Overall, the review summarizes the current knowledge on VM genetics, and provides new insights into potential involvement of biological pathways in VM pathogenesis. We also present an overview of available data regarding the role of epigenetic and environmental factors in VMs. We identify areas where knowledge is lacking, such as precise molecular mechanisms in which specific genes contribute to the development of VMs. Finally, we propose future research avenues that could address knowledge gaps.

Klippel-Feil syndrome (KFS) is a rare congenital disorder characterized by the fusion of cervical vertebrae, limiting neck mobility, and often presenting with clinical manifestations such as neck pain, stiffness, and neurological deficits. While the classical presentation of KFS includes a "clinical triad" comprising a shortened neck, a low posterior hairline, and limited cervical motion, not all patients exhibit all three features. This case report presents an 81-year-old male with the complete KFS triad and underscores the diagnostic challenges and management strategies associated with this condition. Despite the rarity of KFS, understanding it is crucial for clinicians due to its profound implications on patient management and quality of life. This case emphasizes the importance of clinical suspicion in Internal Medicine, showcasing how an isolated presentation may often be a manifestation of an underlying congenital condition.