Apparent cleidocranial dysplasia associated with abnormalities of 8q22 in three individuals

Identification of a Novel Splice Site Mutation in RUNX2 Gene in a Family with Rare Autosomal Dominant Cleidocranial Dysplasia

Background:

Pathogenic variants of RUNX2, a gene that encodes an osteoblast-specific transcription factor, have been shown as the cause of CCD, which is a rare hereditary skeletal and dental disorder with dominant mode of inheritance and a broad range of clinical variability. Due to the relative lack of clinical complications resulting in CCD, the medical diagnosis of this disorder is challenging, which leaves it underdiagnosed.

Methods:

In this study, nine healthy and affected members of an Iranian family were investigated. PCR and sequencing of all exons and exon-intron boundaries of RUNX2 (NM_001024630) gene was performed on proband. Co-segregation analysis was conducted in the other family members for the identified variant. Additionally, a cohort of 100 Iranian ethnicity-matched healthy controls was screened by ARMS-PCR method.

Results:

The novel splice site variant (c.860-2A>G), which was identified in the intron 6 of RUNX2 gene, co-segregated with the disease in the family, and it was absent in healthy controls. Pathogenicity of this variant was determined by several software, including HSF, which predicts the formation or disruption of splice donor sites, splice acceptor sites, exonic splicing silencer sites, and exonic splicing enhancer sites. In silico analysis predicted this novel variant to be disease causing.

Conclusion:

The identified variant is predicted to have an effect on splicing, which leads to exon skipping and producing a truncated protein via introducing a premature stop codon.

Cleidocranial Dysplasia in a 10-year-old Child: A Case Report

Cleidocranial dysplasia is a rare congenital anomaly characterized by multiple skeletal defects of which partial or complete absence of clavicles, delayed closure of fontanels with presence of open sutures and multiple wornian bones forms a striking feature. The oral manifestations are delayed exfoliation, delayed or failing eruption of the permanent dentition with multiple supernumerary teeth, protruding mandible and mid face retrusion. It is also known as Marie and Sainton's disease, mutational dystosis or cleidocranial dysostosis. A 10-year-old female patient reported to the Department of Pedodontics and Preventive Dentistry, Sathyabama University, Dental College and General Hospital, Chennai, Tamil Nadu with the chief complaint of unerupted permanent teeth. Radiological investigations confirmed the diagnosis of cleido cranial dysplasia and various treatment options are discussed in this article.

Cleidocranial dysplasia: Radiological mimic of pyknodysostosis - A case report

Cleidocranial dysplasia (CCD) is a rare autosomal dominant skeletal disorder with predominant membranous bone involvement. It may also occur as a sporadic mutation. The diagnosis of this condition is based on the clinical, radiological and genetic findings. It is characterised by hypoplasia or aplasia of the lateral thirds of the clavicles; craniofacial and dental anomalies; and hypoplastic iliac bones. Pyknodysostosis is a close radiological mimic of this entity. Definite diagnosis is based on the genetic analysis. A 36-year-old short-statured female was referred for computed tomography of the paranasal regions for complaints of a deviated nasal septum and midline depression in her forehead. Skeletal screening demonstrated an open metopic suture, wormian bones, maxillary hypoplasia, maldentition and aplastic lateral thirds of both clavicles. In this article, we report a case of CCD, discuss various overlapping features between CCD and pyknodysostosis and attempt to differentiate them radiologically.

A limb-girdle myopathy phenotype of RUNX2 mutation in a patient with cleidocranial dysplasia: a case study and literature review

Background

Cleidocranial dysplasia (CCD) is a rare hereditary disorder that arises from heterozygous loss of function mutations in the runt-related transcription factor 2 (RUNX2) gene. As RUNX2 is mainly expressed in osteoblasts, CCD typically affects the skeletal and dental systems. Few studies have investigated RUNX2 mutation effects on non-skeletal systems. Here, we describe limb-girdle myopathy, an uncommon phenotype of CCD, in a patient with a heterozygous missense mutation (p.R225Q) in the RUNX2 gene.

Case presentation

A 58 year-old man presented with progressive back pain and six months of weakness in the proximal parts of all four limbs. Physical examinations showed that he was short in stature (height, 164.4 cm; weight, 79.1 kg) with a dysmorphic face, including hypertelorism, midface hypoplasia, and chin protrusion. At a young age, he had received orthodontic surgery, due to dental abnormalities. Neurological examinations revealed sloping shoulders, weakness, and atrophy in the proximal areas of the arms, shoulder girdle muscles, and legs. The deep tendon reflex and sensory system were normal. Radiological examinations revealed mild scoliosis, shortened clavicles, and a depressed skull bone, which were consistent with a clinical diagnosis of CCD. Electromyography (EMG) studies showed myogenic polyphasic waves in the deltoid, biceps brachii, and rectus femoris muscles. Instead, the EMG findings were normal in the first dorsal interosseous, tibialis anterior and facial muscles. The EMG findings were compatible with a limb-girdle pattern with facial sparing. The patient’s family history showed his father and eldest daughter with similar dysmorphic faces, skeletal disorders and proximal upper extremity weakness. We sequenced the RUNX2 gene and discovered a heterozygous missense mutation (c.G674A, p.R225Q), which altered the C-terminal end of the RUNX2 protein. This mutation was predicted to inactivate the protein and might affect its interactions with other proteins. This mutation co-segregated with the disease phenotypes in the family.

Conclusions

We described limb-girdle myopathy in a patient with CCD that carried a heterozygous RUNX2 missense mutation. This uncommon phenotype expanded the phenotypic spectrum of the RUNX2 p.R225Q mutation. The role of RUNX2 in myogenic development merits future studies. Our findings remind clinicians that myopathic patients with myopathies combined with facial dysmorphism and shortened clavicles should consider the diagnosis of CCD.

Cleidocranial dysplasia with autosomal dominant inheritance pattern

Cleidocranial dysplasia (CCD) is an autosomal dominant disease with a wide range of expression, characterized by clavicular hypoplasia, retarded cranial ossification, delayed bone and teeth development, supernumerary teeth, stomatognathic, craniofacial and skeletal abnormalities. This paper presents a case of CCD in a female with brachycephalic skull, depressed frontal bone and nasal bridge, hypoplastic middle one-third of face with mandibular prognathism and hyper mobility of both shoulders with associated radiographic features. Odontologist is often the first professional who patient of CCD approaches, since there is a delay in the eruption or absence of permanent teeth. The premature diagnosis allows a scope for proper treatment modalities, offering a better life quality for patient.

Hypodontia and delayed dentition as the primary manifestation of cleidocranial dysplasia presenting with a diagnostic dilemma

Cleidocranial dysplasia is a rare autosomal disorder which manifests as partial or complete absence of clavicles, multiple supernumerary teeth, and delayed closure of fontanelle. Classical cases of cleidocranial dysplasia are easily diagnosed very early in the life. However, cases with partial manifestation of the syndrome and noncontributory family history are difficult to diagnose. Here, we report a case of 8.5-year-old girl child who presented with delayed tooth development (without any supernumerary teeth), anterior open fontanelle, and normal clavicles, thus resulting in a diagnostic dilemma.

Cleidocranial dysplasia presenting with retained deciduous teeth in a 15-year-old girl: a case report

Introduction

Cleidocranial dysplasia is a rare congenital defect of autosomal dominant inheritance caused by mutations in the Cbfa1 gene, also called Runx2, located on the short arm of chromosome 6. It primarily affects bones which undergo intramembranous ossification. This condition is of clinical significance to dentistry due to the involvement of the facial bones, altered eruption patterns and multiple supernumerary teeth.

Case presentation

Our patient, a 15-year-old Indian girl, presented with the typical features of prolonged retention of deciduous dentition and delayed eruption of permanent teeth, that is, mandibular prognathism along with other skeletal abnormalities like shrugged shoulder and the absence of clavicles. A multidisciplinary approach was followed, comprising orthodontic, surgical and pedodontic teams for management.

Conclusion

Successful treatment of such a case lies in a holistic approach that takes care of all aspects, including the primary pathology, the deformity itself and even the psychological angle.

RUNX2 mutations in Taiwanese patients with cleidocranial dysplasia

Cleidocranial dysplasia (CCD) is an autosomal dominant human skeletal disorder comprising hypoplastic clavicles, wide cranial sutures, supernumerary teeth, short stature, and other skeletal abnormalities. It is known that mutations in the human RUNX2 gene mapped at 6p21 are responsible for CCD. We analyzed the mutation patterns of the RUNX2 gene by direct sequencing in six Taiwanese index cases with typical CCD. One of the patients was a familial case and the others were sporadic cases. Sequencing identified four mutations. Three were caused by single nucleotide substitutions, which created a nonsense (p.R391X), two were missense mutations (p.R190W, p.R225Q), and the forth was a novel mutation (c.1119delC), a one-base deletion. Real time quantitative PCR adapted to determine copy numbers of the promoter, all exons and the 3’UTR region of the RUNX2 gene detected the deletion of a single allele in a sporadic case. The results extend the spectrum of RUNX2 mutations in CCD patients and indicate that complete deletions of the RUNX2 gene should be considered in those CCD patients lacking a point mutation detected by direct sequencing.

Severe cleidocranial dysplasia and hypophosphatasia in a child with microdeletion of the C-terminal region of RUNX2

Cleidocranial dysplasia (CCD) is a rare autosomal dominant skeletal dysplasia due to mutations causing haploinsufficiency of RUNX2, an osteoblast transcription factor specific for bone and cartilage. The classic form of CCD is characterized by delayed closure of the fontanels, hypoplastic or aplastic clavicles and dental anomalies. Clinical reports suggest that a subset of patients with CCD have skeletal changes which mimic hypophosphatasia (HPP). Mutations in RUNX2 are detected in approximately 65% of cases of CCD, and microdeletions occur in 13%. We present clinical and radiological features in a 6-year-old child with severe CCD manifested by absence of the clavicles marked calvarial hypomineralization, osteoporosis and progressive kyphoscoliosis. HPP features included Bowdler spurs, severe osteopenia, and low alkaline phosphatase. Following negative mutation analysis of RUNX2, comparative genomic hybridization (CGH) microarray was performed. The result revealed a microdeletion in RUNX2, disrupting the C-terminal part of the gene.

Clinical spectrum of cleidocranial dysplasia: a case report

Background

Cleidocranial dysplasia is a developmental anomaly of the skeleton and the teeth. This condition may be inherited, be transmitted as dominant characteristics in either sex, or even may appear spontaneously. It presents with skeletal defects of several bones, like partial or complete absence of clavicles, late closure of the fontanels, presence of open skull sutures and multiple wormian bones.

Case presentation

In this case report, we describe an otherwise healthy 30 year-old male with a chief complaint of missing anterior maxillary and Mandibular teeth.

Conclusion

Cleidocranial dysplasia is very rare in occurrence, incidence being 1: 1,000,000. Since early diagnosis of cleidocranial dysplasia is essential for initiating the appropriate treatment approach, clinicians should be aware of the characteristic features. We report a case of cleidocranial dysplasia because of its rarity.

Hypogonadotropic hypogonadism associated with cleidocranial dysostosis

BACKGROUND

Cleidocranial dysostosis (CCD) is a rare autosomal dominant disease with high penetrance and extremely variable expression. Some of the clinical manifestations include large, broad and short cranium with frontal and parietal bossing and a supraglabellar depression, facial part of the cranium relatively small with hypertelorism, absent or poorly defined superior and inferior clavicular depressions.

PATIENT REPORT

A 17 year-old girl with CCD was referred to the pediatric endocrinology and metabolism clinic because she failed to reach any signs of puberty.

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.

Prenatal diagnosis of a cleidocranial dysplasia-like phenotype associated with a de novo balanced t(2q;6q)(q36;q16) translocation

Cleidocranial dysplasia (CCD) is a congenital disorder of bone development characterized by persistently open or delayed closure of cranial sutures and wormian bones, hypoplastic and/or aplastic clavicles, wide pubic symphysis, dental anomalies and short stature. The condition is inherited as an autosomal-dominant trait and the human CBFA1 gene has been identified as the CCD gene. We describe a prenatal form of the skeletal disorder that included clavicular hypoplasia, absence of ossification of the cranial parietal bones and very poor ossification of the frontal and pubic bones. Growth restriction affecting only the long bones was also noted. The fetal karyotype revealed an apparently de novo balanced t(2q;6q)(q36;q16) translocation. This particular form of skeletal disorder associated with the absence of family history and an apparently de novo balanced translocation led the parents to opt for termination of the pregnancy.

Mutations in the RUNX2 gene in patients with cleidocranial dysplasia

Cleidocranial dysplasia (CCD) is a autosomal dominant disorder characterized by skeletal anomalies such as patent fontanels, late closure of cranial sutures with Wormian bones, late erupting secondary dentition, rudimentary clavicles, and short stature. The locus for this disease was mapped to chromosome 6p21. RUNX2 is a member of the runt family of transcription factors and its expression is restricted to developing osteoblasts and a subset of chondrocytes. Mutations in the RUNX2 gene have been shown to cause CCD. Chromosomal translocations, deletions, insertions, nonsense and splice-site mutations, as well as missense mutations of the RUNX2 gene have been described in CCD patients. Although there is a wide spectrum in phenotypic variability ranging from primary dental anomalies to all CCD features plus osteoporosis, no clear phenotype-genotype correlation has been established. However analysis of the three-dimensional structure of the DNA binding runt domain of the RUNX proteins and its interaction with DNA, as well as the cofactor CBFB, start to provide an insight into how missense mutations affect RUNX2 function.

Clavicular hypoplasia, zygomatic arch hypoplasia, and micrognathia: a newly defined syndrome

We report on a 6-year-old boy with a previously undefined syndrome of clavicular hypoplasia, frontonasal malformation, zygomatic arch hypoplasia, micrognathia, and normal intelligence. His condition differs from similar syndromes on the basis of unique facial findings such as microcornea, stellate irises, and a midline maxillary cleft. We present his case, a review of the literature, and propose the acronym CHZAM, for clavicular hypoplasia, zygomatic arch, and micrognathia, to represent this syndrome.

Dihydropyrimidinase deficiency: structural organization, chromosomal localization, and mutation analysis of the human dihydropyrimidinase gene

Dihydropyrimidinase (DHP) deficiency (MIM 222748) is characterized by dihydropyrimidinuria and is associated with a variable clinical phenotype. This disease might be associated with a risk of 5-fluorouracil toxicity, although no cases have been reported. We present here both the molecular characterization of the human DHP gene and, for the first time, the mutations causing DHP deficiency. The human DHP gene spans >80 kb and consists of 10 exons. It has been assigned to 8q22, by FISH. We performed mutation analysis of genomic DNA in one symptomatic and five asymptomatic individuals presenting with dihydropyrimidinuria. We identified one frameshift mutation and five missense mutations. Two related Japanese adult subjects were homozygous for the Q334R substitution, whereas two other, unrelated Japanese infant subjects were heterozygous for the same mutation, but this mutation is not common in the Japanese population. A Caucasian pediatric patient exhibiting epileptic attacks, dysmorphic features, and severe developmental delay was homozygous for W360R. Using a eukaryotic expression system, we showed that all mutations reduced enzyme activity significantly, indicating that these are crucial DHP deficiency-causing mutations. There was no significant difference, in residual activity, between mutations observed in the symptomatic and those observed in the asymptomatic individuals.

Cleidocranial dysplasia with neonatal death due to central nervous system injury in utero: case report and literature review

Cleidocranial dysplasia (CCD), an uncommon disorder involving membranous bones, is rarely lethal in early life. The calvaria is defective and wormian bones are present. Abnormalities of the clavicles vary in severity from a minor unilateral defect to bilateral absence. This report concerns pre- and postmortem anatomical and radiological findings in a 15-day-old female neonate with CCD. Her postnatal course was characterized by seizures and recognition of hydrocephalus during the first day of life. The calvaria was hypoplastic with numerous wormian bones. A pseudofracture of the right clavicle was present. Hydrocephalus was present in the brachycephalic brain which had a severely thinned cerebral cortex. Hemosiderin in the ventricular lining and marked subependymal gliosis were interpreted as evidence of old intraventricular hemorrhage that had occurred in utero. A CCD-related condition, Yunis-Varon syndrome (YVS), is noted for early lethality and for developmental and secondary abnormalities of the central nervous system. The present case only partially matches the phenotype of YVS and might represent a part of a spectrum of phenotypic variants ranging from viable CCD to lethal YVS.

Mapping of the gene for cleidocranial dysplasia in the historical Cape Town (Arnold) kindred and evidence for locus homogeneity

Cleidocranial dysplasia (CCD) is an autosomal dominant disorder, features of which include a patient anterior fontanelle, a bulging calvarium, hypoplasia or aplasia of the clavicles, a wide public symphysis, dental anomalies, vertebral malformation, and short stature. The Cape Town kindred which is under our genetic management was originally described more than four decades ago and now consists of more than 1000 people. Following reports of rearrangements on chromosomes 6 and 8 in people with CCD, we have carried out linkage analyses between highly information microsatellite dinucleotide repeat markers in the rearranged regions and the disorder in a branch of this South African CCD kindred, consisting of 38 subjects, 18 of whom are affected. Maximum lod scores (at theta = 0.00) of 7.14 (for marker D6S459), 4.32 (TCTE), 4.99 (D6S452), 5.97 (D6S269), and 3.95 (D6S465) confirm linkage of the disorder to the short arm of chromosome 6. Our data indicate that the CCD gene is located within a minimal region of approximately 10 cM flanked by the marker D6S451 distally and D6S466 proximally. This information is vital towards isolating and characterising the gene for CCD, and is being used to construct a physical map of 6p21.1-6p21.3. More importantly, mapping of the locus in the South African kindred of mixed ancestry, in which the "founder" of the disorder was of Chinese origin, suggests that a single locus is responsible for classic CCD.

Genetic mapping of the cleidocranial dysplasia (CCD) locus on chromosome band 6p21 to include a microdeletion

Cleidocranial dysplasia (CCD) is a generalized skeletal dysplasia with autosomal dominant inheritance. Recently, the CCD disease locus was localized to 23 [Mundlos et al., 1995] and 17 cM regions [Feldman et al., 1995], of chromosome band 6p21 by linkage studies of seven affected families. Of note, the 23 cM region contained a microdeletion detected in one family at D6S459, an interval that was excluded in the 17 cM overlapping region. Here, linkage of CCD to 6p21 was independently confirmed with a maximal two-point LOD score of Z = 5.12 with marker D6S452 at theta = 0.00. Recombinant events in two affected individuals defined a CCD region of 7 cM from D6S465 to D6S282, which overlapped with the CCD region containing the microdeletion but did not overlap with the 17 cM critical region from D6S282 to D6S291. These results suggest the refined localization of the CCD region to 6 cM spanning markers D6S438 to D6S282, thereby reviving the possibility that the CCD gene lies within the microdeletion at D6S459.

Pericentric inversion of chromosome 6 in a patient with cleidocranial dysplasia

We describe a male patient with a pericentric inversion of chromosome 6 and classic cleidocranial dysplasia (CCD), mild to moderate mental retardation, hearing deficiency, and unusual facial appearance. We conclude that there is a causal relationship between the chromosomal disorder and the CCD.