PUF60 loss-of-function with normal cognition should be considered in the differential diagnosis of Klippel-Feil syndrome.

Klippel-Feil syndrome (KFS) has a genetically heterogeneous phenotype with six known genes, exhibiting both autosomal dominant and autosomal recessive inheritance patterns. PUF60 is a nucleic acid-binding protein, which is involved in a number of nuclear processes, including pre-mRNA splicing, apoptosis, and transcription regulation. Pathogenic variants in this gene have been described in Verheij syndrome due to either 8q24.3 microdeletion or PUF60 single-nucleotide variants. PUF60-associated conditions usually include intellectual disability, among other findings, some overlapping KFS; however, PUF60 is not classically referred to as a KFS gene. Here, we describe a 6-year-old female patient with clinically diagnosed KFS and normal cognition, who harbors a heterozygous de novo variant in the PUF60 gene (c.1179del, p.Ile394Serfs*7). This is a novel frameshift variant, which is predicted to result in a premature stop codon. Clinically, our patient demonstrates a pattern of malformations that matches reported cases of PUF60 variants; however, unlike most others, she has no clear learning difficulties. In light of these findings, we propose that PUF60 should be considered in the differential diagnosis of KFS and that normal cognition should not exclude its testing.

Molecular landscape of congenital vertebral malformations: recent discoveries and future directions.

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.

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.

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.

Klippel-Feil Syndrome with Cervical Diastematomyelia in an Adult with Extensive Cervicothoracic Fusions: Case Report and Review of the Literature.

Split cord malformation (SCM) is a developmental disorder that is usually symptomatic and diagnosed in childhood. The majority of these lesions are in the thoracic and lumbar spine, with only 1%-3% of cases found in the cervical spine. This is a case report of a 55-year-old female patient with an unremarkable medical history who presented with neck pain. Upon workup, she was found to have extensive developmental anomalies throughout her cervical and thoracic spine, including an incidentally found type 2 SCM and multiple autofused vertebrae. There are only 6 similar studies published in the literature. There was extensive facet degeneration in her cervical spine, which was suspected to be the etiology of her neck pain. This case illustrates the rare finding of asymptomatic adult cervical SCM and the likely significance of her autofused vertebrae causing accelerated symptomatic facet spondylosis.

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.

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.

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.

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.

"Sandwich Deformity" in Klippel-Feil syndrome: A "Full-Spectrum" presentation of associated craniovertebral junction abnormalities.

Klippel-Feil syndrome (KFS) is defined as congenital fusion of two or more cervical vertebrae resulting from a segmentation failure in the developing spine. According to Samartzis et al., the most commonly fused segments are found at C2/3 (74.1%) and C6/7 (70.4%). In patients with C2/3 fusion, especially when there is additional C1 occipitalization, several secondary anomalies including atlantoaxial dislocation (AAD), basilar invagination (BI), Chiari malformation, and syringomyelia can be identified. In this report, we present a case of a 12-year-old patient with C2/3 and occipitalization and a "Full-Spectrum" presentation of associated CVJ abnormalities including C0/1 fusion, AAD, BI, Chiari malformation, syringomyelia, myelopathy and cranial neuropathy received neurological decompression of the cervico-medullary junction by posterior reduction of the AAD and reconstruction of her CVJ using an unconventional hybrid construct due to a high-riding right vertebral artery in C2. To our knowledge, her "Full-Spectrum" presentation may include the most categories of concomitant abnormalities in the literature. In addition, She received neurological decompression of the cervico-medullary junction using an unconventional hybrid construct due to a high-riding vertebral artery in C2. Three months after the surgery, all of her symptoms recovered significantly. Neither Chiari malformation nor syringomyelia could be identified by MRI two years after the surgery. At the last follow-up (4 years), the patient became completely asymptomatic.

Fusion of cervical vertebrae from a basal archosauromorph from the Middle Triassic Denwa Formation, Satpura Gondwana Basin, India.

This report describes two adjacent, longitudinally-fused anterior cervical vertebrae from a basal archosauromorph. The specimen was collected from the Denwa Formation, Satpura Gondwana Basin, India. The differential diagnosis of the fusion includes genetic or environmentally-mediated congenital malformations, nonspecific spondyloarthopathy, and various infectious agents. These observations represent the first published recognition of archosauromorph vertebral pathology from specimens that were discovered in India. The observations affirm that basal archosauromorphs suffered from disorders that have been observed in later dinosaurs and modern-day vertebrates. Considering the process of orderly differential diagnosis is an important aspect of understanding lesions of ancient bones.

Congenital Cervical Fusion as a Risk Factor for Development of Degenerative Cervical Myelopathy.

BACKGROUND: Congenital fusion of cervical vertebrae, including Klippel-Feil syndrome (KFS), is a suspected risk factor for development of degenerative cervical myelopathy (DCM). We aimed to establish prevalence and degenerative patterns of congenital cervical fusion (CCF) among a global cohort of patients with DCM. METHODS: Data from 3 prospective DCM studies were merged, including clinical data for 813 patients and imaging for 592 patients. CCF was diagnosed by presence of fused cervical vertebrae without signs of degenerative fusion. A wasp-waist sign was used to define a KFS subgroup. Characteristics of patients with CCF and the KFS subgroup were compared with the remainder of patients with DCM. RESULTS: Twenty-three patients with CCF (14 KFS) were identified, indicating a prevalence of 3.9% (2.4% KFS). Patients with CCF were older (P = 0.02), had more operated levels (P = 0.01), had higher rates of ossified posterior longitudinal ligament (P = 0.02), and demonstrated worse degenerative changes at C3-4, including spinal cord compression (P = 0.002) and T2 weighted image T2WI signal hyperintensity (P = 0.04). Levels adjacent to fusions showed a trend toward increased spinal cord compression (P = 0.09), with fusions at C3-4 or above showing cord compression below in 9 of 10 patients, fusions at C5-6 or below having cord compression above in 8 of 8 patients, and fusions at C4-5 showed cord compression above and below in 2 of 2 patients. CONCLUSIONS: The prevalence of CCF and KFS is higher in DCM than for the general population, suggesting that these patients are predisposed to DCM development. Patients with CCF also have an altered pattern of degenerative changes, seemingly related to adjacent segment degeneration that preferentially affects midcervical levels.

Malignant teratoma in Klippel-Feil syndrome: a case report and review of the literature.

INTRODUCTION: Klippel-Feil syndrome is characterized by a congenital fusion of cervical vertebrae. Intracranial teratomas are nongerminomatous germ cell tumors and they account for 0.3 to 0.9% of all intracranial tumors. Teratomas with malignant transformation refer to lesions which give rise to malignant cancer of somatic type. The association between tumors of dermoid origin and Klippel-Feil malformation is extremely rare. Only 23 other cases have so far been reported, and only one case of dermoid tumor with areas of dedifferentiation on squamous cell carcinoma has been described. CASE PRESENTATION: We report the case of a 72-year-old white man with a 2-year history of gait and balance disturbances. A brain magnetic resonance imaging revealed a fourth ventricle neoplastic process with infiltrative features. He was operated through a suboccipital craniectomy with a C1 laminotomy and bilateral vertebral artery transposition. At 6-months follow-up, magnetic resonance imaging showed an early regrowth of the fourth ventricle tumor, with the same radiological features. CONCLUSIONS: Patients with Klippel-Feil malformation could develop posterior fossa dermoid tumors. The malignant potential of such tumors must be considered and surgery is recommended. Particular attention must be focused on the histopathological analysis in order to identify possible foci of malignant transformation.

Spinal Neurenteric Cyst in Association with Klippel-Feil Syndrome: Case Report and Literature Review.

BACKGROUND: Spinal neurenteric cysts, also known as endodermal or enterogenous cysts, are rare epithelium-lined structures of presumed endodermal origin. Congenital vertebral anomalies are frequently seen in patients with neurenteric cysts, most typically anterior spina bifida, butterfly vertebrae, and hemivertebrae. However, few series of intraspinal neurenteric cysts accompanied by Klippel-Feil syndrome have been reported previously. CASE DESCRIPTION: Our purpose is to present the clinical, radiological, and histological results of a 29-year-old patient with a spinal neurenteric cyst associated with Klippel-Feil syndrome and to review previous reported cases of neurenteric cysts associated with Klippel-Feil syndrome. In our patient, cervical radiography demonstrated C5-T1 vertebral fusion and magnetic resonance imaging revealed a large intradural cystic mass. The cystic lesion was removed successfully, and it was histopathologically diagnosed as a neurenteric cyst. CONCLUSION: Neurenteric cysts should always be considered in the differential diagnosis of an intraspinal cystic mass seen in the setting of vertebral anomalies.

Klippel-Feil syndrome and levo-looped transposition of the great arteries.

Klippel-Feil syndrome is a skeletal disorder characterised by low hairline and a short neck due to abnormal fusion of two or more cervical vertebrae. Although congenital heart and lung defects are infrequent, some abnormalities such as cor triatriatum, coarctation of the aorta, total anomalous pulmonary venous connection, or lung agenesis have been reported. The challenge of recognising Klippel-Feil syndrome lies in the fact that there is an association of this syndrome with other significant conditions such as skeletal, genitourinary, neurological, ear, and some cardiac defects. We report a Klippel-Feil syndrome type III 14-year-old patient with a levo-looped transposition of the great arteries. In addition, the patient had agenesis of the left upper-lung lobe.

[Intubation of a first time parturient with Klippel-Feil syndrome].

We describe a case of a first time parturient with Klippel-Feil syndrome (KFS). KFS is defined by fusion of cervical vertebrae and the clinical triad of low posterior hairline, short wide neck and limited neck movement. KFS represents a complex challenging anaesthesiologic condition due to limited movement of the neck and the risk of irreversible neurologic sequelae if manipulated, as well as unpredictable effect of neuroaxial anaesthesia. We recommend awake fiberoptic intubation for airway management in this rare disorder and stress the necessity of early anaesthesiologic assessment in any cervical spine disorder that might need airway management.