Heterogeneity in Klippel-Feil syndrome: a new classification

Cardiovascular Findings in Klippel-Feil Syndrome: A Systematic Review

Klippel-Feil syndrome (KFS) is a congenital disease defined by an abnormal fusion between cervical vertebrae. Due to the rarity of the disorder, its prevalence, along with its pathogenesis and associated conditions, remains to be clearly defined. The aim of this review is to summarize the findings of all case reports of KFS in PubMed over the last 10 years that describe cardiovascular disease, defects, or abnormalities. A total of 43 articles containing 46 reports were included from the 157 case reports considered. Cases were reviewed for commonality in biological sex and vertebral fusion and level using the Samartzis classification system to determine what association, if any, exists with the cardiovascular findings analyzed. A total of 72% of cases reported one or more findings consistent with congenital heart disease. Using the Samartzis classification system, type III KFS was the most common fusion profile overall in this subset of patients. The heterogeneity of disease manifestations makes the treatment and management of KFS case-dependent, though current guidelines highlight the importance of a multidisciplinary care team for pediatric patients. Our findings support this notion and provide evidence for the inclusion of a care provider who specializes in cardiovascular medicine in patients of all ages, as well as the consideration of additional diagnostic screening exams for cardiovascular abnormalities. Future studies into the embryological origin of KFS and a more robust search for a genetic marker are needed to better understand the development of the disease and its various associated conditions.

Klippel-Feil Syndrome With Isolated Facial Dysmorphism: A Clinical Conundrum With Resemblance to Adenoid Facies

Klippel-Feil syndrome (KFS) is a triad comprising cervical spine fusion, a low posterior hairline, and constrained neck movement. This triad is not universally present. The most frequent accompaniment is Sprengel's scapula deformity. According to the Feil classification, Class 1 (C1) is an immense fusion of many cervical vertebrae, Class 2 (C2) is a fusion of one or two vertebrae only, and Class 3 (C3) is coupled with thoracic and lumbar spinal vertebral fusion in addition to the fusion of the cervical vertebrae. Clarke's categorization of KFS includes other associated anomalies. The different classification systems for KFS have been made by the different specialists to whom patients may present, which include orthopedic surgeons, neurosurgeons, orthodontists, faciomaxillary surgeons, cardiologists, and pediatricians. This anomaly being rare and the lack of universally accepted classification may lead to confusion regarding the identification of the syndrome, especially the Clarke Type 3 with isolated facial dysmorphism may go undiagnosed. We report a case with KFS-Clarke Type 3 with isolated facial dysmorphism and Feil Type 2 with the fusion of C2-C3 cervical vertebrae, detected as an incidental radiologic finding, and initial impression of adenoid facies. Hence, this case also highlights the contrasting features between the facial dysmorphism of Clarke Type 3 KFS and adenoid facies.

Klippel-Feil Syndrome: morphological findings in a 19th-century musealized skull from Viana del Bollo (Orense, Spain)

The aim of this study is to show the cranial alterations that Klippel-Feil syndrome produced in a case older than 200 years. Few paleopathological case studies diagnosed as Klippel-Feil Syndrome are focused on cranial abnormalities. A skull numbered 778, belonging to the Federico Olóriz Aguilera collection (Spain, 19th century AD), Universidad Complutense de Madrid, belonging to a young man born in a town in the North of Spain, was investigated. This cranium was visually inspected, hence macroscopically and paleoradiologically studied, using the images obtained through conventional radiology and CT scan imaging. In addition to the vertebral fusion between the atlas (C1) and the axis (C2), atlanto-occipital fusion, basilar impression, obliteration of the sagittal suture, enlarged parietal foramina and significant craniofacial asymmetry affecting maxillary bones, sphenoid, orbits, nasal bones and both palatines were observed. Morphological findings make it possible to diagnose a Klippel-Feil syndrome, possibly type-II, although the lack of the rest of the spinal column renders it impossible to verify other spinal anomalies. As a limitation, only the cranium and two cervical vertebrae were preserved, hence the possible involvement of the rest of the skeleton cannot be verified.

LRRTM4 Terminal Exon Duplicated in Family with Tourette Syndrome, Autism and ADHD

Tourette syndrome (TS) is a neurodevelopmental disorder characterised by motor and vocal tics and strong association with autistic deficits, obsessive–compulsive disorder (OCD) and attention-deficit/hyperactivity disorder (ADHD). The genetic overlap between TS and autism spectrum disorder (ASD) includes those genes that encode the neurexin trans-synaptic connexus (NTSC) inclusive of the presynaptic neurexins (NRXNs) and postsynaptic neuroligins (NLGNs), cerebellin precursors (CBLNs in complex with the glutamate ionotropic receptor deltas (GRIDs)) and the leucine-rich repeat transmembrane proteins (LRRTMs). In this study, we report the first evidence of a TS and ASD association with yet another NTSC gene family member, namely LRRTM4. Duplication of the terminal exon of LRRTM4 was found in two females with TS from the same family (mother and daughter) in association with autistic traits and ASD.

The craniovertebral junction, between osseous variants and abnormalities: insight from a paleo-osteological study

The bony components of the craniovertebral junction (CVJ) have been investigated in 172 skeletons, dug up from several archaeological sites, to define the frequency of developmental dysmorphisms, and to acquire qualitative and quantitative data about their morphology. A review of the pertinent literature is also presented. Twenty-five individuals (14.5%) exhibited at least one dysmorphism, which ranged from a condition of simple variant to a true malformation. Four individuals presented two or more anomalies at the same time (2.3% of the whole sample, 16% of the affected individuals). The most frequently observed abnormalities were: (i) the presence of a complete bony bridge in the atlas, forming a canal surrounding the vertebral artery (arcuate foramen, supertransverse foramen, and the simultaneous occurrence of arcuate foramen and supertransverse foramen); (ii) the presence of basilar processes. Basilar processes displayed a great variety in shape and dimension. They also differed with respect to their relationship with atlas and axis. The less frequently detected anomalies were: (i) complete absence of the posterior arch of C1, (ii) fusion of C2 and C3, and (iii) irregular segmentation of C2. A broad array of structural defects has been described at the CVJ. They may occur either isolated or as part of complex multisystem syndromes. Although harmless in many cases, they can notwithstanding cause severe, even life-threatening complications. When unrecognized, they may generate trouble during surgery. Hence, accurate knowledge of CVJ arrangement, including its multifarious variations, is a critical issue for radiologists, clinicians, surgeons, and chiropractors.

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.

Familial occurrence of skeletal developmental anomalies as a reflection of biological relationships in a genealogically documented Central European sample (19th to 20th centuries)

Skeletal developmental anomalies (SDA) are a subject of constant interest across scientific disciplines, but still mostly as isolates and curiosities. The aim of this study was to find out to what extent the occurrence of SDA reflects documented biological relationships. The skeletal remains of 34 individuals with known genealogical data were available, members of one family over four generations (19th to 20th centuries, Bohemia, Czech Republic), including some inbred individuals. The occurrence of 89 SDA was assessed on the basis of scopic morphological evaluation and X-ray and CT examinations. The degree of similarity between individuals was calculated using a "similarity coefficient" (SC). A linear model was used to test the relationship between positive values of the SC and the relatedness of biologically related individuals. Simultaneously, based on population frequencies of the evaluated anomalies, those that could be considered familial were recorded. A statistically significant relationship between morphological similarity and the biological distance between individuals was found. The greatest similarity was found among close relatives such as parents and children, siblings, or grandparents and grandchildren. The effect of increased consanguinity on the occurrence of anomalies was not confirmed, however. Seventeen SDA shared by closely related individuals were found in the sample, supporting the documented family relationships among them. Eleven of these were selected as possibly familial, but only five were statistically significant: an elongated styloid process, a cervical block vertebrae (arch, facet joints), hamate hamulus aplasia, anteater nose sign, and incomplete fusion of the S1 spinous process. There were also 28 cases of individual occurrences of 17 different SDA, without connection to the documented relationships between individuals.

Klippel-Feil syndrome cases from Slovakia

OBJECTIVE

This study analyzes two probable cases of Klippel-Feil syndrome (KFS) from the region of modern Slovakia and provides an overview of possible cases reported in 'grey' literature.

MATERIALS

Two adult skeletons with probable KFS from Vráble-Veľké Lehemby and Radoľa-Koscelisko.

METHODS

Macroscopic analysis was performed using standard osteological methods.

RESULTS

The two analyzed skeletons represent probable cases of KFS; one from the Neolithic, and one from the Middle Ages. Additional cases of potential KFS have been indicated within the 'grey' literature.

CONCLUSIONS

The study shows that KFS was present in prehistoric eastern Central Europe. The few cases of ancient rare diseases may be a result of past and present bioarcheological research, and many cases are hidden within 'grey' literature. A re-examination of older datasets is vital.

SIGNIFICANCE

The described cases from modern Slovakia contributes to a limited list of archaeological cases, thus widening our knowledge about the occurrence of this rare condition throughout Europe in the past.

LIMITATIONS

The state of past and present osteo-archaeological research in eastern Central Europe, poor preservation of some remains, and lack of pathognomonic features associated with KFS.

SUGGESTIONS FOR FURTHER RESEARCH

Systematic review of older skeletal assemblages and 'grey' literature.

Developmental basis of trachea-esophageal birth defects

Trachea-esophageal defects (TEDs), including esophageal atresia (EA), tracheoesophageal fistula (TEF), and laryngeal-tracheoesophageal clefts (LTEC), are a spectrum of life-threatening congenital anomalies in which the trachea and esophagus do not form properly. Up until recently, the developmental basis of these conditions and how the trachea and esophagus arise from a common fetal foregut was poorly understood. However, with significant advances in human genetics, organoids, and animal models, and integrating single cell genomics with high resolution imaging, we are revealing the molecular and cellular mechanisms that orchestrate tracheoesophageal morphogenesis and how disruption in these processes leads to birth defects. Here we review the current understanding of the genetic and developmental basis of TEDs. We suggest future opportunities for integrating developmental mechanisms elucidated from animals and organoids with human genetics and clinical data to gain insight into the genotype-phenotype basis of these heterogeneous birth defects. Finally, we envision how this will enhance diagnosis, improve treatment, and perhaps one day, lead to new tissue replacement therapy.

Klippel Feil Syndrome: Clinical Phenotypes Associated With Surgical Treatment

STUDY DESIGN

Retrospective study.

OBJECTIVE

To define distinct Klippel-Feil syndrome (KFS) patient phenotypes that are associated with the need for surgical intervention.

SUMMARY OF BACKGROUND DATA

KFS is characterized by the congenital fusion of cervical vertebrae; however, patients often present with a variety of other spinal and extraspinal anomalies suggesting this syndrome encompasses a heterogeneous patient population. Moreover, it remains unclear how the abnormalities seen in KFS correlate to neurological outcomes and the need for surgical intervention.

METHODS

Principal component (PC) analysis was performed on 132 KFS patients treated at a large pediatric hospital between 1981 and 2018. Thirty-five variables pertaining to patient/disease-related factors were examined. Significant PCs were included as independent variables in multivariable logistic regression models designed to test associations with three primary outcomes: cervical spine surgery, thoracolumbar/sacral spine surgery, and cranial surgery.

RESULTS

Fourteen significant PCs accounting for 70% of the variance were identified. Five components, representing four distinct phenotypes, were significantly associated with surgical intervention. The first group consisted of predominantly subaxial cervical spine fusions, thoracic spine abnormalities and was associated with thoracolumbar/sacral spine surgery. The second group was largely represented by axial cervical spine anomalies and had high association with cervical subluxation and cervical spine surgery. A third group, heavily represented by Chiari malformation, was associated with cranial surgery. Lastly, a fourth group was defined by thoracic vertebral anomalies and associations with sacral agenesis and scoliosis. This phenotype was associated with thoracolumbar/sacral spine surgery.

CONCLUSION

This is the first data-driven analysis designed to relate KFS patient phenotypes to surgical intervention and provides important insight that may inform targeted follow-up regimens and surgical decision-making.

LEVEL OF EVIDENCE

3.

Developmental anomalies and South American paleopathology: A comparison of block vertebrae and co-occurring axial anomalies among three skeletal samples from the El Brujo archaeological complex of northern coastal Peru

Though developmental anomalies have been noted for over a century in South American paleopathology, they have received less attention than other pathological conditions. When anomalies are reported, they tend to be unusual case studies or incidental findings. Paleopathological research should also consider anomalies from a population perspective, to broaden our understanding about the frequency of specific anomalies, and potentially offer insight into genetic relationships, cultural behavior, or environmental factors. This investigation compared block vertebrae and co-occurring postcranial axial anomalies among three skeletal samples reflecting an occupational sequence at the El Brujo Archaeological Complex of Peru. Block vertebrae demonstrate both considerable antiquity and persistence through time, though frequencies, vertebral level, and co-occurring anomalies varied by sex and cultural period. Among the Late Preceramic sample, the frequency of C2-C3 block vertebrae was highest and only seen among females, which may suggest familial influence, genetic isolation, and potentially matrilocality. The Moche sample demonstrated a moderate frequency of blocks, which in combination with the frequencies of other developmental anomalies, may suggest population continuity paired with an influx of new genes, demographic expansion, and possible cultural change with regard to postmarital residence. The Lambayeque sample demonstrated the lowest frequency of blocks and the highest frequency and greatest diversity of anomalies, which may suggest genetic continuity from the Moche, an expanded gene pool, broader opportunities for mate choice, and cultural change. It is hoped that this investigation will provide data for future comparisons and call attention to the need for the broader study of developmental anomalies in South America.

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.

Otolaryngologic Manifestations of Klippel-Feil Syndrome in Children

Importance

Children with Klippel-Feil syndrome (KFS), characterized principally by abnormal fusion of 2 or more cervical vertebrae, may have many additional congenital anomalies. The overall prevalence of otolaryngologic manifestations among patients with KFS has not been previously characterized.

Objective

To define the otolaryngologic diagnoses made and procedures performed in 95 patients with KFS, which, to our knowledge, is the largest series of this challenging patient population published to date.

Design, Setting, and Participants

For this retrospective review, all patients with KFS who underwent otolaryngology consultation at our institution over a 26-year period (January 1989 to December 2015) were included. Patients were identified using International Classification of Diseases, Ninth Revision (ICD-9) codes and were confirmed through individual medical record review. Relevant otolaryngologic diagnoses and procedures were extracted using ICD-9 and Current Procedural Terminology codes, respectively. Selected demographics included age, sex, number of clinic visits, and number of procedures.

Main Outcomes and Measures

The primary outcomes were the otolaryngologic diagnoses and procedures associated with the KFS patient population; the secondary outcome was Cormack-Lehane classification documented during airway procedures.

Results

Overall, 95 patients with KFS were included in this study (55 males [58%] and 40 females [42%]); mean (range) age at time of presentation to the otorhinolaryngology clinic was 5.8 (birth-23.0) years. Each patient with KFS averaged 8 visits to the otorhinolaryngology office and 5 otolaryngologic diagnoses. The most common diagnosis was conductive hearing loss (n = 49 [52%]), followed by sensorineural hearing loss (n = 38 [40%]), and dysphagia (n = 37 [39%]). Sixty-two (65%) patients underwent otolaryngologic procedures, with 44 (46%) undergoing multiple procedures. The most common procedure was tympanostomy tube placement (n = 36 [38%]), followed by office flexible endoscopy (n = 23 [24%]). Twelve of the 20 patients who underwent direct laryngoscopy had documented Cormack-Lehane classification; 5 of 12 patients (42%) had a compromised view (grade 2, 3, or 4) of the larynx. Three patients required tracheotomies at this institution for airway stabilization purposes; each had severe upper airway obstruction leading to respiratory failure.

Conclusions and Relevance

Patients with KFS require consultation for a variety of otolaryngologic conditions. Among these, hearing loss is the most common, but airway issues related to cervical spine fusion are the most challenging. Formulating an appropriate care plan in advance is paramount, even for routine otolaryngology procedures.

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.

The prevalence of Klippel-Feil syndrome in pediatric patients: analysis of 831 CT scans

Background

To evaluate the prevalence of Klippel-Feil syndrome (KFS) in pediatric patients obtaining cervical CT imaging in the emergency room (ER).

Methods

We evaluated CT scans of the cervical spine of pediatric patients treated in the ER of a Level I Trauma Center from January 2013 to December 2015. Along with analysis of the CT scans for KFS, the following demographics were collected: age, sex, race and ethnicity. Mechanism of injury was also established for all patients. If KFS was present, it was classified using Samartzis classification as type I (single level fusion), type II (multiple, noncontiguous fused segments) or type III (multiple, contiguous fused segments).

Results

Of the 848 cervical CTs taken for pediatric ER patients during the study period, 831 were included. Of these patients, 10 had KFS, a prevalence of 1.2%. According to Samartzis classification, 9 were type I and 1 type III. The average age of patients with KFS was 16.02 years (10-18 years), with 8 males (80%) and 2 females (20%). Three had congenital fusions at vertebral levels C2-C3, two at C3-C4, three at C5-C6, one at C6-C7, and one with multiple levels of cervical fusion.

Conclusions

The prevalence of KFS amongst 831 pediatric patients, who underwent cervical CT imaging over a 3-year period, was 1.2% (approximately 1 in 83). The most commonly fused spinal levels were C2-C3 and C5-C6. The prevalence of KFS in our study was higher than previously described, and thus warrants monitoring.

Neurocristopathies: New insights 150 years after the neural crest discovery

The neural crest (NC) is a transient, multipotent and migratory cell population that generates an astonishingly diverse array of cell types during vertebrate development. These cells, which originate from the ectoderm in a region lateral to the neural plate in the neural fold, give rise to neurons, glia, melanocytes, chondrocytes, smooth muscle cells, odontoblasts and neuroendocrine cells, among others. Neurocristopathies (NCP) are a class of pathologies occurring in vertebrates, especially in humans that result from the abnormal specification, migration, differentiation or death of neural crest cells during embryonic development. Various pigment, skin, thyroid and hearing disorders, craniofacial and heart abnormalities, malfunctions of the digestive tract and tumors can also be considered as neurocristopathies. In this review we revisit the current classification and propose a new way to classify NCP based on the embryonic origin of the affected tissues, on recent findings regarding the molecular mechanisms that drive NC formation, and on the increased complexity of current molecular embryology techniques.

The intriguing history of vertebral fusion anomalies: the Klippel-Feil syndrome

INTRODUCTION

Our knowledge and understanding of vertebral fusion, defined and eponymously known as Klippel-Feil syndrome in the early 1900s, have a long history. This uncommon finding has been identified as early as 500 B.C. in an Egyptian mummy. Many more examples of spinal vertebra fusion have been described by Greek historians and recovered by archeologists demonstrating this entity's rich history.

CONCLUSIONS

Klippel-Feil syndrome is a rare skeletal anomaly characterized by abnormal fusion of two or more vertebrae. With the advent of newer molecular technology and genetic discoveries, we now have a better understanding of the etiology and possible pathogenesis of this disease.

Monsters and the case of L. Joseph: André Feil's thesis on the origin of the Klippel-Feil syndrome and a social transformation of medicine

André Feil (1884–1955) was a French physician best recognized for his description, coauthored with Maurice Klippel, of patients with congenital fusion of cervical vertebrae, a condition currently known as Klippel-Feil syndrome. However, little is known about his background aside from the fact that he was a student of Klippel and a physician who took a keen interest in describing congenital anomalies. Despite the relative lack of information on Feil, his contributions to the fields of spinal disease and teratology extended far beyond science to play an integral role in changing the misguided perception shrouding patients with disfigurements, defects, deformities, and so-called monstrous births. In particular, Feil's 1919 medical school thesis on cervical abnormalities was a critical publication in defying long-held theory and opinion that human “monstrosities,” anomalies, developmental abnormalities, and altered congenital physicality were a consequence of sinful behavior or a reversion to a primitive state. Indeed, his thesis on a spinal deformity centering on his patient, L. Joseph, was at the vanguard for a new view of a patient as nothing less than fully human, no matter his or her physicality or appearance.

Prevalence of Klippel-Feil Syndrome in a Surgical Series of Patients with Cervical Spondylotic Myelopathy: Analysis of the Prospective, Multicenter AOSpine North America Study

Study Design Prospective study. Objective To evaluate the prevalence of Klippel-Feil syndrome (KFS) in a prospective data set of patients undergoing surgical treatment for cervical spondylotic myelopathy (CSM) and to evaluate if magnetic resonance imaging (MRI) features in patients with KFS are more pronounced than those of non-KFS patients with CSM. Methods A retrospective analysis of baseline MRI data from the AOSpine prospective and multicenter CSM-North American study was conducted. All the patients presented with at least one clinical sign of myelopathy and underwent decompression surgery. The MRIs and radiographs were reviewed by three investigators. The clinical and imaging findings were compared with patients without KFS but with CSM. Results Imaging analysis discovered 5 of 131 patients with CSM (∼3.82%) had single-level congenital fusion of the cervical spine. The site of fusion differed for all the patients. One patient underwent posterior surgery and four patients received anterior surgery. Postoperative follow-up was available for four of the five patients with KFS and indicated stable or improved functional status. All five patients demonstrated pathologic changes of adjacent segments and hyperintensity signal changes in the spinal cord on T2-weighted MRI. Multiple MRI features, most notably maximum canal compromise (p = 0.05) and T2 signal hyperintensity area (p = 0.05), were worse in patients with CSM and KFS. Conclusions The high prevalence of KFS in our surgical series of patients with CSM may serve as an indication that these patients are prone to increased biomechanical use of segments adjacent to fused vertebra. This supposition is supported by a tendency of patients with KFS to present with more extensive MRI evidence of degeneration than non-KFS patients with CSM.

Klippel - Feil Syndrome Associated with Congential Heart Disease Presentaion of Cases and a Review of the Curent Literature

First time described in 1912, from Maurice Klippel and Andre Feil independently, Klippel-Feil syndrome (synonyms: cervical vertebra fusion syndrome, Klippel-Feil deformity, Klippel-Feil sequence disorder) is a bone disorder characterized by the abnormal joining (fusion) of two or more spinal bones in the neck (cervical vertebrae), which is present from birth. Three major features result from this abnormality: a short neck, a limited range of motion in the neck, and a low hairline at the back of the head. Most affected people have one or two of these characteristic features. Less than half of all individuals with Klippel-Feil syndrome have all three classic features of this condition.

Since first classification from Feil in three categories (I – III) other classification systems have been advocated to describe the anomalies, predict the potential problems, and guide treatment decisions. Patients with Klippel-Feil syndrome usually present with the disease during childhood, but may present later in life. The challenge to the clinician is to recognize the associated anomalies that can occur with Klippel-Feil syndrome and to perform the appropriate workup for diagnosis.

A case report of amyotrophic lateral sclerosis in a patient with Klippel-Feil syndrome—a familial occurrence: a potential role of TGF-β signaling pathway

The rationale for this article is a description of a unique, familial case of a patient with amyotrophic lateral sclerosis (ALS), a progressive neurodegenerative disorder of unknown etiology coexisting with Klippel-Feil syndrome (KFS), a congenital malformation of cervical vertebrae, characterized by a fusion of minimum 2 cervical vertebrae. We report a 68-year-old man with moderate dysarthria, fasciculations, short neck, hearing deficit, and low posterior hairline. Definite ALS was diagnosed based on neurological abnormalities and electromyography results. Magnetic resonance imaging and computed tomography showed bony abnormalities of the craniocervical junction, fusion of 2 cervical vertebrae, and syringomyelia at the level of C6-C7. KFS phenotype was noted in 2 more family members, and patient's stepsister with KFS phenotype died due to ALS. The pedigree of our family suggests an autosomal-dominant inheritance of both syndromes. Cosegregation of ALS and KFS with an autosomal-dominant trait suggests an impairment of transforming growth factor β signaling pathway, and its potential role is discussed. Further evaluation of patients with autosomal-dominant and sporadic KFS by genetic testing, biochemical measurements, such as plasma transforming growth factor β1, and systematic follow-up electromyography seems warranted.

Coexistence of Left Internal Carotid Agenesis, Klippel-Feil Syndrome and Postaxial Polydactyly

Background

Internal carotid artery agenesis is a rare anomaly that can be clinically asymptomatic. Klippel-Feil syndrome is a skeletal malformation characterized by vertebral fusion. Presence of postaxial polydactyly is suggestive of an underlying syndrome.

Case Report

We report a rare case of a 44-year-old patient with non-specific symptoms and an association between these three rare abnormalities. Vascular anomalies were found using intracranial MR angiography and multi-detector CT angiography of the supraaortic arteries.

Conclusions

Presence of a single aforementioned anomaly requires cautious imaging assessment in order to detect possible associated anomalies and avoid diagnostic pitfalls. A possible common genetic background could explain the coexistence of these three anomalies.

Whole exome sequencing identifies a POLRID mutation segregating in a father and two daughters with findings of Klippel-Feil and Treacher Collins syndromes

We report on a father and his two daughters diagnosed with Klippel-Feil syndrome (KFS) but with craniofacial differences (zygomatic and mandibular hypoplasia and cleft palate) and external ear abnormalities suggestive of Treacher Collins syndrome (TCS). The diagnosis of KFS was favored, given that the neck anomalies were the predominant manifestations, and that the diagnosis predated later recognition of the association between spinal segmentation abnormalities and TCS. Genetic heterogeneity and the rarity of large families with KFS have limited the ability to identify mutations by traditional methods. Whole exome sequencing identified a nonsynonymous mutation in POLR1D (subunit of RNA polymerase I and II): exon2:c.T332C:p.L111P. Mutations in POLR1D are present in about 5% of individuals diagnosed with TCS. We propose that this mutation is causal in this family, suggesting a pathogenetic link between KFS and TCS.

Imaging of the craniovertebral junction anomalies in children

The craniovertebral junction (CVJ) is interposed between the unsegmented skull and the segmented spine; it is functionally unique as it allows the complex motion of the head. Because of its unique anatomy, numerous craniometric indices have been devised. Because of its complex embryology, different from that of the adjacent skull and spine, it is commonly the seat of malformations. Because of the mobility of the head, and its relative weight, the craniovertebral junction is vulnerable to trauma. Like the rest of the axial skeleton, it may be affected by many varieties of dysplasia. In addition, the bony craniovertebral junction contains the neural craniovertebral junction and its surrounding CSF: any bony instability or loss of the normal anatomic relationships may therefore compromise the neural axis. In addition, the obstruction of the meningeal spaces at this level can compromise the normal dynamics of the CSF and result in hydrocephalus and/or syringohydromyelia. To image the CVJ, plain X-rays are essentially useless. MR is optimal in depicting the soft tissues (including the neural axis) and the joints, as well as the bone itself. CT still may be important to better demonstrate the bony abnormalities.

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.

Xq26.3 microdeletion in a male with Wildervanck Syndrome

BACKGROUND

Wildervanck Syndrome (WS; cervico-oculo-acoustic syndrome) consists of Duane retraction syndrome (DRS), the Klippel-Feil anomaly, and congenital deafness. It is much more common in females than males and could be due to an X-linked mutation that is lethal to hemizygous males. We present the genetic evaluation of a male with WS and his family.

MATERIALS AND METHODS

Clinical evaluation and neuroimaging, sequencing of candidate genes, and array comparative genomic hybridization.

RESULTS

The patient had bilateral type 1 DRS, fusion of almost the entire cervical spine, and bilateral severe sensorineural hearing loss due to bilateral cochlear dysplasia; he also had congenital heart disease requiring surgery. His parents were unrelated, and he had eight unaffected siblings. The patient had no mutation found by Sanger sequencing of HOXA1, KIF21A, SALL4, and CHN1. He had a 3kB deletion in the X-chromosome at Xq26.3 that was not found in his mother, one unaffected sibling, or 56 healthy controls of matching ethnicity. This deletion encompassed only one gene, Fibroblast Growth Factor Homologous Factor 13 (FGF13), which encodes a 216-amino acid protein that acts intracellularly in neurons throughout brain development.

CONCLUSIONS

Analysis of this patient's phenotype and genotype open the possibility that X-chromosome deletions may be a cause of WS with larger deletions being lethal to males and that FGF13 mutations may be a cause of WS.

Cervical scoliosis in the Klippel-Feil patient

STUDY DESIGN

Retrospective study.

OBJECTIVE

This study addressed in patients with Klippel-Feil syndrome (KFS), the role of congenitally fused cervical patterns, risk factors, and cervical symptoms associated with cervical scoliosis.

SUMMARY OF BACKGROUND DATA

KFS is an uncommon condition, characterized as improper segmentation of one or more cervical spine segments with or without associated spinal or extraspinal manifestations. "Scoliosis" is potentially the most common manifestation associated with KFS. However, the role of congenitally fused cervical patterns along with additional potential risk factors and their association with cervical scoliosis, and its relationship with cervical spine-related symptoms remain largely unknown.

METHODS

Plain radiographs were utilized to assess the location of congenitally fused cervical segments (O-T1), degree of coronal cervical alignment, and any additional cervical and thoracic spine abnormalities. The classification scheme, as proposed by Samartzis et al of congenitally fused cervical patterns (Types I-III) in KFS patients, was utilized and additional fusion and region-specific patterns were assessed. Patients with coronal cervical alignments of 10° or greater were regarded scoliotic. Patient demographics and the presence of cervical spine-related symptoms were also assessed.

RESULTS

Thirty KFS patients were assessed (mean age, 13.5 yr). The mean coronal cervical alignment was 18.7° and scoliosis was noted in 16 patients. Patients that exhibited congenital fusion of the mid and lower cervical spine region, had multiple, contiguous congenitally fused segments (Type III), and associated vertebral malformations (e.g., hemivertebrae) were highly associated with the presence of cervical scoliosis (P < 0.05). Ten patients exhibited cervical spine-related symptoms; however, no statistically significant difference was noted between the presence of symptoms and coronal cervical alignment (P = 0.815) and cervical scoliosis (P = 0.450).

CONCLUSION

The study noted a prevalence of cervical scoliosis to occur in 53.3% of young KFS patients. Such patients that exhibited congenital fusion of the mid and lower cervical spine region, had multiple, contiguous congenitally fused segments (Type III), and associated vertebral malformations (e.g., hemivertebrae) were highly associated with the presence of cervical scoliosis. However, in young KFS patients, the presence of cervical scoliosis may not be associated with the manifestation of cervical spine-related symptoms.

Failure of cervical arthroplasty in a patient with adjacent segment disease associated with Klippel-Feil syndrome

Cervical arthroplasty may be justified in patients with Klippel-Feil syndrome (KFS) in order to preserve cervical motion. The aim of this paper is to report an arthroplasty failure in a patient with KFS. A 36-year-old woman with KFS underwent two-level arthroplasty for adjacent segment disc degeneration. Anterior migration of the cranial prosthesis was encountered 5 months postoperatively and was successfully revised with anterior cervical fusion. Cervical arthroplasty in an extensively stiff and fused neck is challenging and may lead to catastrophic failure. Although motion preservation is desirable in KFS, the special biomechanical features may hinder arthroplasty. Fusion or hybrid constructs may represent more reasonable options, especially when multiple fused segments are present.

Pilot assessment of a radiologic classification system for segmentation defects of the vertebrae

Existing nomenclature systems for describing and reporting congenital segmentation defects of the vertebrae (SDV) are confusing, inconsistently applied, and lack molecular genetic advances. Our aim was to develop and assess a new classification system for SDV. A multidisciplinary group of the International Consortium for Vertebral Anomalies and Scoliosis (ICVAS) developed a new classification system for SDV, and 5 members group (Group 1) independently classified 10 previously unseen cases using this system. Inter-observer reliability was assessed using kappa, which compares observed agreement with that expected by chance. Seven independent general radiologists unaffiliated with the ICVAS (Group 2) classified the same 10 cases (total, 70 scores) before and after the ICVAS system was explained. We demonstrated the following: Inter-observer reliability for Group 1 yielded a kappa value of 0.21 (95% confidence intervals (CI) 0.052, 0.366, P = 0.0046); A consensus diagnosis was established for the 10 cases. For Group 2, before the ICVAS system was explained, 1 of 70 scores (1.4%) agreed with the Group 1 consensus diagnoses; Group 2 offered 12 different diagnoses, but 38 of 70 (54.3%) responses were "Don't Know." After the ICVAS system was explained, 47 of 70 responses (67.1%; 95% CI 55.5, 77.0) agreed with the Group 1 consensus, an improvement of 65.7% (95% CI 52.5, 75.6, P < 0.00005), with no "Don't Know" responses. Group 2 average reporting times, before and after explanation of the ICVAS system, were 148 and 48 min, respectively. We conclude that the ICVAS radiological classification system was found to be reliable and applicable for 10 SDV phenotypes.

Progress in the understanding of the genetic etiology of vertebral segmentation disorders in humans

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. This review explores (1) 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; (2) outcomes of molecular studies elucidating genetic contributions to congenital and sporadic vertebral malformation; and (3) complex interrelationships between genetic and environmental factors that contribute to the pathogenesis of isolated syndromic and nonsyndromic congenital vertebral malformation. Discussion includes exploration 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.

Unveiling the bmp13 enigma: redundant morphogen or crucial regulator?

Bone morphogenetic proteins are a diverse group of morphogens with influences not only on bone tissue, as the nomenclature suggests, but on multiple tissues in the body and often at crucial and influential periods in development.

The purpose of this review is to identify and discuss current knowledge of one vertebrate BMP, Bone Morphogenetic Protein 13 (BMP13), from a variety of research fields, in order to clarify BMP13's functional contribution to developing and maintaining healthy tissues, and to identify potential future research directions for this intriguing morphogen. BMP13 is highly evolutionarily conserved (active domain >95%) across diverse species from Zebrafish to humans, suggesting a crucial function. In addition, mutations in BMP13 have recently been associated with Klippel-Feil Syndrome, causative of numerous skeletal and developmental defects including spinal disc fusion. The specific nature of BMP13's crucial function is, however, not yet known.

The literature for BMP13 is focused largely on its activity in the healing of tendon-like tissues, or in comparisons with other BMP family molecules for whom a clear function in embryo development or osteogenic differentiation has been identified. There is a paucity of detailed information regarding BMP13 protein activity, structure or protein processing. Whilst some activity in the stimulation of osteogenic or cartilaginous gene expression has been reported, and BMP13 expression is found in post natal cartilage and tendon tissues, there appears to be a redundancy of function in the BMP family, with several members capable of stimulating similar tissue responses. This review aims to summarise the known or potential role(s) for BMP13 in a variety of biological systems.

Klippel-Feil syndrome and associated ear anomalies

BACKGROUND AND PURPOSE

Klippel-Feil syndrome (KFS) is a congenital segmentation anomaly of the cervical vertebrae that manifests as short neck, low hair line, and limited neck mobility. Various systemic malformations may also accompany the syndrome including wide variety of otopathologies affecting all 3 compartments of the ear (external, middle, and inner ear) as well as internal acoustic canal and vestibular aqueduct. We aimed to investigate these involvements and their clinical correlates in a group of patients with KFS.

MATERIALS, METHODS, AND RESULTS

We present 20 KFS cases, of which 12 (% 60) displayed most of the reported ear abnormalities such as microtia, external ear canal stenosis, chronic ear inflammations and their sequels, anomalies of the tympanic cavity and ossicles, inner ear dysplasies, deformed internal acoustic canal, and wide vestibular aqueduct, which are demonstrated using the methods of otoscopy, audiologic testing, and temporal bone computed tomography.

CONCLUSIONS

This series represents one of the highest reported rate of ear involvement in KFS. We found no correlation between the identified ear pathologies and the skeletal and extraskeletal malformations. The genetic nature of the syndrome was supported by the existence of affected family members in 4 (20%) of the cases.

The extent of fusion within the congenital Klippel-Feil segment

STUDY DESIGN

Retrospective radiographic review.

OBJECTIVE

To evaluate in patients with Klippel-Feil syndrome (KFS) the presence and extent of specific fusion patterns across involved cervical segments and their association with age-specific parameters.

SUMMARY OF BACKGROUND DATA

While the radiographic hallmark of KFS is characterized by congenital fusion of at least one cervical motion segment, the relation between age and the extent of segmental congenital fusion remains speculative.

METHODS

A radiographic review of 31 patients with KFS at a single institution. Plain radiographs were used to assess fusion across the vertebral segment as entailing the anterior elements, posterior elements, or complete segment from O-T1. Age-specific stratifications were also performed.

RESULTS

A mean of 3.7 fused segments and a sum of 116 fused segments were noted. From C2-T1, complete fusion of the involved segment represented 77.8% at 10 years or older, 87.5% at 15 years or older, 91.7% at 16 years or older, 95.7% at 17 years or older, 86.5% who were skeletally mature, and 100% at adulthood. Similar trends were not noted for segments of O-C2. In absence of complete segmental fusion, the posterior elements exhibited a higher incidence of fusion than the anterior elements. Statistically significant differences between anterior/posterior to complete segmental fusion with respect to different age markers entailed segments of C2-C3, C4-C5, and C6-C7 (P < 0.05).

CONCLUSION

This study provides some insight into the potential developmental aspects of the extent of segmental fusion of the cervical spine in patients with KFS. In older patients, complete fusion of involved fused segments was more prevalent in regards to C2-T1; however, such an observation was not noted for segments from O-C2. In the absence of complete segmental fusion, fusion of the posterior elements was more often noted than fusion of the anterior elements. Awareness of the varied phenotypic expression of segmental fusion patterns of the cervical spine in patients with KFS underlines theimportance of thorough evaluation of the cervical spine to assess the presence and extent of segmental fusion to facilitate in the identification of neurologic risk factors.

Congenital anomalies of the cervical spine

There are numerous congenital anomalies of the cervical spine. They can be simple and clinically inconsequential to complex with serious neurologic and structural implications. They can occur in isolation or as one of several maldeveloped organs in the patients. Many are discovered incidentally. The more common anomalies seen by pediatric spine surgeons include defects of the anterior or posterior arches of C1, occipital assimilation of the atlas, basilar invagination or impression, os odontoideum, and Klippel-Feil syndrome. Management begins with a detailed history, physical examination, and imaging studies. In general, those lesions that are causing or have caused neurologic injury, chronic pain, or spinal deformity or place the patient at high risk for developing these require treatment.

Klippel-Feil syndrome with other associated anomalies in a medieval Portuguese skeleton (13th-15th century)

Klippel-Feil syndrome, or synostosis of the cervical spine, is the result of an abnormal division of somites during embryonic development. This report analyses an adult male (exhumed from a Portuguese graveyard dating from the 13th to the 15th century) with malformations in the cranium and vertebral column. Besides the lesions that are typical of Klippel-Feil syndrome type II, other defects usually linked to this pathology are described (occipito-atlantal fusion, hemivertebrae, butterfly vertebrae, cervical rib, changes in normal number of vertebral segments and a possible Sprengel deformity).

Sprengel's deformity in Klippel-Feil syndrome

STUDY DESIGN

A retrospective study.

OBJECTIVES

To address the role of congenitally fused cervical segments, the degree of cervical scoliosis, and other risk factors on the presence of Sprengel's deformity (SD) in young patients with Klippel-Feil syndrome (KFS).

SUMMARY OF BACKGROUND DATA

Numerous abnormalities are associated with KFS, one of the most common being SD. It has been postulated that more severe forms of KFS may be more associated with extraspinal manifestations, such as SD.

METHODS

Thirty KFS patients from a single institution were reviewed. Cervical neutral lateral/dynamic/anteroposterior and thoracic anteroposterior plain radiographs were assessed. Radiographically, occipitalization (O-C1), number of congenitally fused segments (C1-T1), classification type (Types I-III), degree of cervical scoliosis, and the presence of SD was assessed. Clinical chart review entailed patient demographics and evidence of the clinical assessment of SD. The threshold for statistical significance was P < 0.05.

RESULTS

There were 11 males (36.7%) and 19 females (63.3%) with a mean age of 13.5 years (range, 2.7-26.3 years). Occipitalization was present in 10 (33.3%) individuals and C2-C3 was the most common level fused (70.0%). The mean number of congenitally fused segments was 3.3 (range, 1-6 levels). The mean degree of cervical scoliosis was 17.3 degrees (range, 0 degrees-67 degrees). There were 6 (20%) Type I, 15 Type II (50.0%), and 9 Type III (30%) patients. SD was noted in 5 (16.7%) of the patients. Four patients had unilateral, whereas 1 patient had bilateral SD. There was 4.0 and 3.1 mean number of congenitally fused segments in patients with or without SD, respectively. SD did not occur in Type I patients (single fused block). The presence of SD was found to be nonsignificant regarding sex type (P = 0.327), presence of occipitalization (P = 0.300), number of congenitally fused segments (P = 0.246), specific congenitally fused segments (P > 0.05), classification type (P > 0.05), and scoliosis (P = 0.702).

CONCLUSION

SD occurred in 16.7% of KFS patients. Sex type, number of congenitally fused segments, specific fused patterns, occipitalization, classification type, and the degree of cervical scoliosis did not seem to be significantly associated with the presence of SD in KFS patients in our series. Thorough examination for the presence and degree of SD in KFS is necessary, irrespective of the extent of cervical abnormalities. Alternatively, the treating physician should not dismiss a thorough cervical spine examination in patients with SD, evaluating factors that may predispose the KFS patient to an increased risk of neurologic injury.

The genetics and embryology of zebrafish metamerism

Somites are the most obvious metameric structures in the vertebrate embryo. They are mesodermal segments that form in bilateral pairs flanking the notochord and are created sequentially in an anterior to posterior sequence concomitant with the posterior growth of the trunk and tail. Zebrafish somitogenesis is regulated by a clock that causes cells in the presomitic mesoderm (PSM) to undergo cyclical activation and repression of several notch pathway genes. Coordinated oscillation among neighboring cells manifests as stripes of gene expression that pass through the cells of the PSM in a posterior to anterior direction. As axial growth continually adds new cells to the posterior tail bud, cells of the PSM become relatively less posterior. This gradual assumption of a more anterior position occurs over developmental time and constitutes part of a maturation process that governs morphological segmentation in conjunction with the clock. Segment morphogenesis involves a mesenchymal to epithelial transition as prospective border cells at the anterior end of the mesenchymal PSM adopt a polarized, columnar morphology and surround a mesenchymal core of cells. The segmental pattern influences the development of the somite derivatives such as the myotome, and the myotome reciprocates to affect the formation of segment boundaries. While somites appear to be serially homologous, there may be variation in the segmentation mechanism along the body axis. Moreover, whereas the genetic architecture of the zebrafish, mouse, and chick segmentation clocks shares many common elements, there is evidence that the gene networks have undergone independent modification during evolution.