Otolaryngological manifestations of cleidocranial dysplasia, concentrating on audiological findings

Rare Findings in Cleidocranial Dysplasia Caused by RUNX Mutation

Background  Cleidocranial dysplasia (CCD, #MIM119600) is an autosomal-dominant skeletal dysplasia characterized by delayed closure of the cranial sutures, aplasia, or hypoplasia of the clavicles and dental abnormalities. These findings were accompanied by mobile and drooping shoulders, frontal and parietal bossing, hypertelorism, brachycephaly, short stature, supernumerary, and late erupting teeth. Radiographic studies can reveal involvement of multiple bones including skull, chest, pelvis, and limbs. CCD can be diagnosed with clinical and radiological evaluation and validated by molecular studies. Heterozygous loss of function RUNX2 gene, which plays an important role in osteogenesis and differentiation of precursor cells, causes CCD phenotype.

Methods  In this article, we reported five cases from three unrelated families with CCD phenotype. All exons and exonic–intronic boundary regions of RUNX2 gene from five patients were analyzed by polymerase chain reaction amplification and direct Sanger-sequencing.

Results  Our patients had classical CCD phenotype and we detected three different previously described mutations including c.1171C > T, IVS4 + 4delAAGT and c.676G > A. However, nail dysplasia has never been associated with these mutations. Our patients had varying degrees of nail dysplasia. Two of three mutations are related with Runt DNA-binding domain of RUNX2 protein in Wnt signaling and c.1171C > T had effect on proline/serine/threonine-rich (PST) domain. Recently, Wnt signaling pathway was presented as a key regulator of digit and nail differentiation. Our data suggest that RUNX2 gene may have an essential role on embryogenesis of nails, probably by protecting their integrity.

Cleidocranial Dysplasia-dental Disorder Treatment and Audiology Diagnosis

A review of numerous case reports was made, in order to demonstrate the possibilities for treatment of dental disorders in patients with Cleidocranial dysplasia (CCD). In this paper, our own report, including a diagnosis of the effect on the auditory system, is presented. In addition to the triad of CCD symptoms that include hypoplastic or aplastic clavicles, impacted and supernumerary teeth, delayed closure of fontanelles and cranial sutures, impairment of the hearing system resulting in conductive hearing loss also occurs. Our own report is based on the case of a 12-year-old CCD patient, in whom Cone Beam Computed Tomography (CBCT) revealed the presence of 12 supernumerary teeth. Furthermore, a clinical examination pointed to the presence of retained deciduous teeth and a delayed eruption of permanent teeth. Orthodontic-surgical procedures were implemented, in accordance with the literature. During the course of the orthodontic treatment, a decrease in auditory sensitivity was observed, for which reason hearing tests were also performed. Conductive hearing loss was detected. As such, it is important to remember that in such cases, auditory check-ups need to be performed between the many surgical and orthodontic interventions, which usually last a few years.

Cleidocranial dysplasia with hearing loss

Cleidocranial dysplasia is an inherited skeletal anomaly that affects primarily the skull, clavicle, and dentition, which can occur spontaneously, but most are inherited in autosomal dominant mode. The skull findings are brachycephaly, delayed or failed closure of the fontanelles, presence of open skull sutures and multiple wormian bones with pronounced frontal bossing. The syndrome is notable for aplasia or hypoplasia of the clavicles. The neck appears long and narrow and the shoulders markedly droop. Oral manifestations exhibit a hypoplastic maxilla with high-arched palate. Crowding of teeth is produced by retention of deciduous teeth, delayed eruption of permanent teeth, and the presence of a large number of unerupted supernumerary teeth. We report a case of CCD in a 12-year-old girl who presented with an unaesthetic facial appearance, unerupted permanent dentition with hearing loss.

Regulation of postnatal bone homeostasis by TGFβ

Perhaps more so than any other tissue, bone has pivotal mechanical and biological functions. Underlying the ability of bone to execute these functions, whether providing structural support or preserving mineral homeostasis, is the dynamic remodeling of bone matrix. Cells within bone integrate multiple stimuli to balance the deposition and resorption of bone matrix. Transforming growth factor-β (TGFβ) uniquely coordinates bone cell activity to maintain bone homeostasis. TGFβ regulates the differentiation and function of both osteoblasts and osteoclasts, from lineage recruitment to terminal differentiation, to balance bone formation and resorption. TGFβ calibrates the synthesis and material quality of bone matrix and bone's responsiveness to applied mechanical loads. Therefore, by coupling the activity of bone forming and resorbing cells, and by sensing, responding to and defining physical cues, TGFβ integrates physical and biochemical stimuli to maintain bone homeostasis. Disruption of TGFβ signaling has significant consequences on bone mass and quality. Alternatively, TGFβ is a powerful lever that has the potential to yield therapeutic benefit in cases where bone homeostasis needs to be recalibrated.

Otolaryngologic manifestations of skeletal dysplasias in children

This article reviews some of the otolaryngologic manifestations of skeletal dysplasias. Achondroplasia is discussed most comprehensively. Skeletal dysplasias are bone and cartilage disorders that disrupt the development of the long bones, craniofacial skeleton, and vertebral column, with the most notable characteristic being short stature. Children with skeletal dysplasias have various medical problems. These children often develop head and neck manifestations of their disorders. Hearing loss, middle ear disease, and respiratory difficulties are seen in these children. Otolaryngologists must be knowledgeable about these disorders to diagnose, treat, and appropriately refer children with skeletal dysplasias.

Sh3pxd2b mice are a model for craniofacial dysmorphology and otitis media

Craniofacial defects that occur through gene mutation during development increase vulnerability to eustachian tube dysfunction. These defects can lead to an increased incidence of otitis media. We examined the effects of a mutation in the Sh3pxd2b gene (Sh3pxd2b^nee) on the progression of otitis media and hearing impairment at various developmental stages. We found that all mice that had the Sh3pxd2b^nee mutation went on to develop craniofacial dysmorphologies and subsequently otitis media, by as early as 11 days of age. We found noteworthy changes in cilia and goblet cells of the middle ear mucosa in Sh3pxd2b^nee mutant mice using scanning electronic microscopy. By measuring craniofacial dimensions, we determined for the first time in an animal model that this mouse has altered eustachian tube morphology consistent with a more horizontal position of the eustachian tube. All mutants were found to have hearing impairment. Expression of TNF-α and TLR2, which correlates with inflammation in otitis media, was up-regulated in the ears of mutant mice when examined by immunohistochemistry and semi-quantitative RT-PCR. The mouse model with a mutation in the Sh3pxd2b gene (Sh3pxd2b^nee) mirrors craniofacial dysmorphology and otitis media in humans.

Cleidocranial dysplasia

Cleidocranial dysplasia is a rare autosomal dominant condition with generalized dysplasia of bone, characterized by delayed closer of cranial sutures, hypoplastic or aplastic clavicles, short stature, dental abnormalities and a variety of other skeletal abnormalities. We present a seven-year-old female child presenting with classical features of cleidocranial dysplasia.

Tissue-specific calibration of extracellular matrix material properties by transforming growth factor-β and Runx2 in bone is required for hearing

Physical cues, such as extracellular matrix stiffness, direct cell differentiation and support tissue-specific function. Perturbation of these cues underlies diverse pathologies, including osteoarthritis, cardiovascular disease and cancer. However, the molecular mechanisms that establish tissue-specific material properties and link them to healthy tissue function are unknown. We show that Runx2, a key lineage-specific transcription factor, regulates the material properties of bone matrix through the same transforming growth factor-β (TGFβ)-responsive pathway that controls osteoblast differentiation. Deregulated TGFβ or Runx2 function compromises the distinctly hard cochlear bone matrix and causes hearing loss, as seen in human cleidocranial dysplasia. In Runx2+/⁻ mice, inhibition of TGFβ signalling rescues both the material properties of the defective matrix, and hearing. This study elucidates the unknown cause of hearing loss in cleidocranial dysplasia, and demonstrates that a molecular pathway controlling cell differentiation also defines material properties of extracellular matrix. Furthermore, our results suggest that the careful regulation of these properties is essential for healthy tissue function.

Craniofacial and temporal bone CT findings in cleidocranial dysplasia

Cleidocranial dysplasia (CCD) is a multistructural polyostotic genetic disorder that results from mutation of the CBFA1 gene. Hearing loss is a frequent finding in CCD. We describe the CT craniofacial findings in CCD and provide a comprehensive discussion of the CT temporal bone findings in these patients.

Cleidocranial dysplasia - review with an emphasis on otological and audiological manifestations

Cleidocranial dysplasia is a rare developmental abnormality of bone that affects both the skeleton and the temporal bone. It is genetically characterized and the clinical signs and symptoms can be diverse. Aural pathologies may be the presenting symptoms of the disease. We reviewed the up to date literature on the syndrome with an emphasis on the otological and audiological manifestation.

Cleidocranial dysplasia in a mother and her daughter within the scope of neurosurgery

Cleidocranial dysplasia is an autosomal-dominant disorder characterized by late closure or nonclosure of the anterior fontanelle, late ossification of cranial sutures, defective clavicle, and delayed eruption of permanent teeth. In this article, two cases of cleidocranial dysplasia involving a mother and her daughter are reported, and a case management policy is suggested. The 1-year-old daughter was macrocephalic and brachycephalic, and had midface hypoplasia and hypertelorism. Plain radiographs revealed aplasia of the clavicles. Three-dimensional computerized tomography scanning demonstrated a large anterior fontanelle, a patent posterior fontanelle, and bone defects at the pterion and asterion, together with nonfused metopic and sagittal sutures. The mother was 22 years of age. She had an open anterior fontanelle, aplastic clavicles, and unerupted permanent teeth. Although it is a rare disorder, cleidocranial dysplasia should be recognized by neurosurgeons. A protective helmet can be provided in early childhood, and craniofacial remodeling can be undertaken at a later age, when the final size and shape of the skull become apparent.

Cleido cranial dysplasia: report of a family

A family case of Cleidocranial Dysplasia is presented. A mother and two adolescent girls were examined. In all three cases, a radiological series was performed over the entire body. Generalized dysplasia in bones, prolonged retention of primary teeth, and delayed eruption of permanent, as well as supernumerary teeth was diagnosed. The citogenetic study with GTG band showed normal 46, XX. Bilateral audiometry in the mother demonstrated a mild to moderate hypoacustic condition. Radiological findings are presented and the importance of early diagnosis is discussed.