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.

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.

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.

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.

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)

A novel syndrome of Klippel-Feil anomaly, myopathy, and characteristic facies is linked to a null mutation in MYO18B.

BACKGROUND: Klippel-Feil anomaly (KFA) can be seen in a number of syndromes. We describe an apparently novel syndromic association with KFA. METHODS: Clinical phenotyping of two consanguineous families followed by combined autozygome/exome analysis. RESULTS: Two patients from two apparently unrelated families shared a strikingly similar phenotype characterised by KFA, myopathy, mild short stature, microcephaly, and distinctive facies. They shared a single founder autozygous interval in which whole exome sequencing revealed a truncating mutation in MYO18B. There was virtually complete loss of the transcript in peripheral blood, indicative of nonsense-mediated decay. Electron microscopy of muscle confirms abnormal myosin filaments with accompanying myopathic changes. CONCLUSIONS: Deficiency of MYO18B is linked to a novel developmental disorder which combines KFA with myopathy. This suggests a widespread developmental role for this gene in humans, as observed for its murine ortholog.

Hemp, an mbt domain-containing protein, plays essential roles in hematopoietic stem cell function and skeletal formation.

To clarify the molecular pathways governing hematopoietic stem cell (HSC) development, we screened a fetal liver (FL) HSC cDNA library and identified a unique gene, hematopoietic expressed mammalian polycomb (hemp), encoding a protein with a zinc-finger domain and four malignant brain tumor (mbt) repeats. To investigate its biological role, we generated mice lacking Hemp (hemp(-/-)). Hemp(-/-) mice exhibited a variety of skeletal malformations and died soon after birth. In the FL, hemp was preferentially expressed in the HSC and early progenitor cell fractions, and analyses of fetal hematopoiesis revealed that the number of FL mononuclear cells, including HSCs, was reduced markedly in hemp(-/-) embryos, especially during early development. In addition, colony-forming and competitive repopulation assays demonstrated that the proliferative and reconstitution abilities of hemp(-/-) FL HSCs were significantly impaired. Microarray analysis revealed alterations in the expression levels of several genes implicated in hematopoietic development and differentiation in hemp(-/-) FL HSCs. These results demonstrate that Hemp, an mbt-containing protein, plays essential roles in HSC function and skeletal formation. It is also hypothesized that Hemp might be involved in certain congenital diseases, such as Klippel-Feil anomaly.

Klippel-Feil syndrome and Dandy-Walker malformation.

The Klippel-Feil deformity is a complex of osseous and visceral anomalies, which include low hairline, platybasia, fused cervical vertebrae with a short neck, and deafness. Associated central nervous system abnormalities include occipital cephalocele, Chiari I malformation, syrinx, microcephaly, and hydrocephalus. Herein, we report a case with Klippel-Feil syndrome and Dandy-Walker malformation.

The hair collar sign as a marker for neural tube defects.

The hair collar sign has been described as a marker of cranial dysraphism, including encephaloceles, meningoceles, and heterotropic brain tissue. This report describes a male born with a hair collar sign who subsequently was found to have a Klippel-Feil anomaly, diastematomyelia, multiple segmental spine and rib anomalies, and a translocation between chromosomes 1 and 4; t(1;4) (q44;q10). While not previously documented, spine abnormalities may be an associated abnormality with the hair collar sign. Physicians should consider radiographic evaluation of the spine in all newborns with a hair collar sign, as well as genetic screening.

Cervico-oculo-Acoustic syndrome in a male with consanguineous parents.

BACKGROUND: The cervico-oculo-acoustic syndrome comprises Klippel-Feil anomaly, sensorineural deafness and Duane's retraction syndrome. Polygenic, autosomal dominant, and X-linked inheritance have been hypothesized. The disorder has rarely been reported in males. CASE REPORT: A 42-year-old male, born of consanguineous parents, presented with Duane's syndrome, mixed hearing loss, C2-C3 fusion, neck stiffness, and right facial palsy. A variety of cardiac, neurological and urogenital anomalies occurred in his relatives. The electro-oculographic studies showed impaired abduction and adduction of the right eye and impaired abduction of the left eye. Vergence, vertical eye movements and peripheral vestibular responses were normal. Somatosensory evoked potentials showed absence of the N13 peak and brainstem auditory evoked potentials bilateral delay of the I-III interpeak latencies. CONCLUSIONS: Consanguinity of the patient's parents, not previously reported, suggests autosomal recessive inheritance, but autosomal dominant inheritance is indicated by the family history. The pattern of the oculomotor deficit is consistent with bilateral dysplasia of the abducens nuclei with preserved internuclear neurons in the right abducens nucleus. Neurophysiological investigations revealed lower brainstem and cervical cord involvement.

Sindrome de Klippel-Feil con agenesia de vagina, fistula rectovulvar y electrodactilla: presentación de un caso / Klippel-Feil syndrome whith absent vagina, recto vulvar fistula and ectrodactyly: a case report

Se describe el caso de una paciente de 19 años de edad con malformaciones congénitas múltiples propias del Síndrome de Kippel-Feil, con ectrodactilia de dedo medio en mano derecha, y ausencia de vagina con fístula recto vulvar, resuelta quirúrgicamente per prima sin colostomía temoral derivativa. Tratándose de un caso esporádico, se revisaron antecedentes bibliográficos que permiten compararlo con casos similares reportados para su clasificación y determinación de tipo de herencia.

Mandibular distraction osteogenesis in a neonate.

Children with craniofacial anomalies are predisposed to airway obstruction and frequently require airway intervention. Tracheotomy is performed when the airway obstruction is severe and refractory to other less invasive interventions. Tracheotomy is associated with significant morbidity, and there is a trend noted in the literature toward achieving earlier decannulation by the institution of definitive structural changes to the mandible. Mandibular distraction osteogenesis has been shown to alleviate airway obstruction in the pediatric population. We report a case in which mandibular distraction osteogenesis was successfully carried out in a neonate with acute airway obstruction at birth as a result of combined Pierre Robin sequence and Klippel-Feil syndrome. After 1 year, the patient still had an adequate airway with tolerable scarring and no neurologic sequelae.

Cervico-oculo-acoustic syndrome.

A 12-year-old boy with the cervico-oculo-acoustic syndrome, which comprises Duane retraction syndrome, Klippel-Feil anomaly (fused cervical vertebrae) and congenital hearing loss, is described. To this classical triad an optic nerve head coloboma was associated. To the authors' knowledge this is the first case in which such an association has been recorded.