Temporal gene expression profiling during early-stage traumatic temporomandibular joint bony ankylosis in a sheep model

BACKGROUND

Investigating the molecular biology underpinning the early-stage of traumatic temporomandibular joint (TMJ) ankylosis is crucial for discovering new ways to prevent the disease. This study aimed to explore the dynamic changes of transcriptome from the intra-articular hematoma or the newly generated ankylosed callus during the onset and early progression of TMJ ankylosis.

METHODS

Based on a well-established sheep model of TMJ bony ankylosis, the genome-wide microarray data were obtained from samples at postoperative Days 1, 4, 7, 9, 11, 14 and 28, with intra-articular hematoma at Day 1 serving as controls. Fold changes in gene expression values were measured, and genes were identified via clustering based on time series analysis and further categorised into three major temporal classes: increased, variable and decreased expression groups. The genes in these three temporal groups were further analysed to reveal pathways and establish their biological significance.

RESULTS

Osteoblastic and angiogenetic genes were found to be significantly expressed in the increased expression group. Genes linked to inflammation and osteoclasts were found in the decreased expression group. The various biological processes and pathways related to each temporal expression group were identified, and the increased expression group comprised genes exclusively involved in the following pathways: Hippo signaling pathway, Wnt signaling pathway and Rap 1 signaling pathway. The decreased expression group comprised genes exclusively involved in immune-related pathways and osteoclast differentiation. The variable expression group consisted of genes associated with DNA replication, DNA repair and DNA recombination. Significant biological pathways and transcription factors expressed at each time point postoperatively were also identified.

CONCLUSIONS

These data, for the first time, presented the temporal gene expression profiling and reveal the important process of molecular biology in the early-stage of traumatic TMJ bony ankylosis. The findings might contributed to identifying potential targets for the treatment of TMJ ankylosis.

Autosomal recessive mental retardation, deafness, ankylosis, and mild hypophosphatemia associated with a novel ANKH mutation in a consanguineous family

CONTEXT

Mutations in ANKH cause the highly divergent conditions familial chondrocalcinosis and craniometaphyseal dysplasia. The gene product ANK is supposed to regulate tissue mineralization by transporting pyrophosphate to the extracellular space.

OBJECTIVE

We evaluated several family members of a large consanguineous family with mental retardation, deafness, and ankylosis. We compared their skeletal, metabolic, and serological parameters to that of the autosomal recessive progressive ankylosis (ank) mouse mutant, caused by a loss-of-function mutation in the murine ortholog Ank.

PARTICIPANTS

The studied patients had painful small joint soft-tissue calcifications, progressive spondylarthropathy, osteopenia, mild hypophosphatemia, mixed hearing loss, and mental retardation.

RESULTS

After mapping the disease gene to 5p15, we identified the novel homozygous ANK missense mutation L244S in all patients. Although L244 is a highly conserved amino acid, the mutated ANK protein was detected at normal levels at the plasma membrane in primary patient fibroblasts. The phenotype was highly congruent with the autosomal recessive progressive ankylosis (ank) mouse mutant. This indicates a loss-of-function effect of the L244S mutation despite normal ANK protein expression. Interestingly, our analyses revealed that the primary step of joint degeneration is fibrosis and mineralization of articular soft tissues. Moreover, heterozygous carriers of the L244S mutation showed mild osteoarthritis without metabolic alterations, pathological calcifications, or central nervous system involvement.

CONCLUSION

Beyond the description of the first human progressive ankylosis phenotype, our results indicate that ANK influences articular soft tissues commonly involved in degenerative joint disorders. Furthermore, this human disorder provides the first direct evidence for a role of ANK in the central nervous system.

A novel dominant-negative mutation in Gdf5 generated by ENU mutagenesis impairs joint formation and causes osteoarthritis in mice

Growth and differentiation factor 5 (GDF5) has been implicated in chondrogenesis and joint formation, and an association of GDF5 and osteoarthritis (OA) has been reported recently. However, the in vivo function of GDF5 remains mostly unclarified. Although various human GDF5 mutations and their phenotypic consequences have been described, only loss-of-function mutations that cause brachypodism (shortening and joint ankylosis of the digits) have been reported in mice. Here, we report a new Gdf5 allele derived from a large-scale N-ethyl-N-nitrosourea mutagenesis screen. This allele carries an amino acid substitution (W408R) in a highly conserved region of the active signaling domain of the GDF5 protein. The mutation is semi-dominant, showing brachypodism and ankylosis in heterozygotes and much more severe brachypodism, ankylosis of the knee joint and malformation with early-onset OA of the elbow joint in homozygotes. The mutant GDF5 protein is secreted and dimerizes normally, but inhibits the function of the wild-type GDF5 protein in a dominant-negative fashion. This study further highlights a critical role of GDF5 in joint formation and the development of OA, and this mouse should serve as a good model for OA.

Osteoprotegerin plasma levels are strongly associated with polymorphisms in human homologue of the mouse progressive ankylosis (ANKH) gene

Osteoprotegerin inhibits osteoclastogenesis and plays an important role in the control of bone resorption. However, the genetic mechanisms underlying regulation of OPG levels are currently not fully elucidated. The aim of the present study was to determine whether the ANKH gene, which plays a central role in bone mineralization, contributes to the genetic regulation of OPG levels. A family-based association study used a sample of 159 ethnically homogeneous nuclear families, comprising 556 apparently healthy individuals. Statistical analyses included family aggregation analysis of OPG variation and four types of transmission disequilibrium tests. Each individual was genotyped for 11 SNPs in the ANKH gene. Four TDTs consistently showed a highly significant association between OPG levels and the intronic SNP rs875525 located between exons 6 and 7. The combined p-value for four tests to reject the null hypothesis of no association was 0.0003. Furthermore, haplotypes generated between rs875525 and two additional neighbouring SNPs (rs2291943 and rs2288474) also revealed a significant association with OPG plasma levels (p < 10(-4)-10(-3)). ANKH genetic polymorphisms in the area between SNP rs2291943 and rs2288474 are strongly associated with OPG plasma levels. The molecular mechanism underlying this association is not obvious, and therefore these results should be regarded cautiously until they are confirmed in independent studies.

A novel mutation in GDF5 causes autosomal dominant symphalangism in two Chinese families

Proximal symphalangism (SYM1) is an autosomal dominant disorder characterized by ankylosis of the proximal interphalangeal joints and fusion of carpal and tarsal bones. We identified and characterized two five-generation Chinese families with SYM1. The two families share some similarities (e.g., osseous fusion of interphalangeal joints of the 2-4 fingers) with SYM1 families with mutations in the NOG gene or the family with mutation R438L recently reported in the GDF5 gene (encoding a bone morphogenetic protein family member). However, they show some unique features including the absence of cuboid bone, the lack of shortness of the first and fifth metacarpal bones, and manifestation of flat feet. Genome-wide linkage analysis of the two families mapped the disease gene to marker D20S112 with a combined LOD score of 4.32. Mutational analysis revealed a novel E491K mutation in the GDF5 gene in both families. The mutation occurs at a highly conserved residue in the TGF-beta domain of GDF5 and represents the second GDF5 mutation identified for SYM1 to date. The E491K mutation co-segregated with the affected individuals in the two families, and did not exist in unaffected family members or 200 normal controls. These results indicate that defects in GDF5 can cause SYM1 in the Chinese population, and expand the spectrum of clinical phenotypes associated with mutant GDF5.

Mineral formation in joints caused by complete or joint-specific loss of ANK function

To reveal the ANK complete loss of function phenotype in mice, we generated conditional and null alleles. Mice homozygous for the null allele exhibited widespread joint mineralization, similar in severity to animals harboring the original ank allele. A delayed yet similar phenotype was observed in mice with joint-specific loss of ANK function.

INTRODUCTION

The ANK pyrophosphate regulator was originally identified and proposed to play a key role in articular cartilage maintenance based on a single spontaneous mouse mutation (ank) that causes severe generalized arthritis. A number of human mutations have subsequently been reported in the human ortholog (ANKH), some of which produce skull and long bone defects with no apparent defects in joints or articular cartilage. None of the currently known mouse or human mutations clearly eliminate the function of the endogenous gene.

MATERIALS AND METHODS

Two new Ank alleles were generated using homologous recombination in mouse embryonic stem (ES) cells. Joint range of motion assays and muCT studies were used to quantitatively assess phenotypic severity in wildtype, heterozygous, and homozygous mice carrying either the null (Anknull) or original (Ankank) allele. A Gdf5-Cre expressing line was crossed to mice harboring the conditional (Ankfloxp) allele to eliminate ANK function specifically in the joints. Histological stains and beta-galactosidase (LACZ) activity were used to determine the correlation between local loss of ANK function and defective joint phenotypes.

RESULTS

Anknull/Anknull mice develop severe ectopic postnatal crystal deposition in almost every joint of the body, leading to eventual joint fusion and loss of mobility. The severity of phenotype in these mice is indistinguishable from that of Ankank/Ankank mice. In addition, despite the widespread expression of Ank in many tissues, the specific deletion of Ank in joints also produces joint mineralization and ankylosis.

CONCLUSIONS

These studies show that ANK function is required locally in joints to inhibit mineral formation and that the Ank gene plays a key role in postnatal maintenance of joint mobility and function.

Stapes ankylosis in a family with a novel NOG mutation: otologic features of the facioaudiosymphalangism syndrome

OBJECTIVE

To report the phenotype-genotype correlation in a Belgian family that was ascertained to have a novel missense mutation in the NOG gene mapping to chromosome 17q22.

STUDY DESIGN

To describe the phenotype, a retrospective case study was performed based on the otologic, audiologic, ophthalmologic, and radiologic data of the mutation carriers of the NOG gene.

SETTING

Tertiary referral center.

PATIENTS

All members of a Belgian kindred who carried the novel missense mutation in the NOG gene (NOG, Trp205Cys [W205C]; 1426G>C).

INTERVENTIONS

Diagnostic otologic and ophthalmologic examination, audiometric analysis, and radiologic imaging.

MAIN OUTCOME MEASURES

Phenotype-genotype correlations.

RESULTS

All five mutation carriers had a typical facies. Bilateral proximal symphalangism and hyperopia were present in 80%. Five of 10 ears also had progressive early-onset conductive hearing loss caused by stapes ankylosis.

CONCLUSIONS

So far, 14 independent NOG mutations have been identified. The autosomal dominant disorder described in the present family was caused by a novel NOG missense mutation (NOG, Trp205Cys [W205C]; 1426G>C). The phenotype correlated well with the facioaudiosymphalangism syndrome. The mutation carriers demonstrated progressive multiple joint fusions, hyperopia, early-onset conductive deafness, and a typical facies.

Genetic characterisation of spontaneous ankylosing arthropathy with unique inheritance from Fas-deficient strains of mice

BACKGROUND

The spontaneous onset of macroscopic arthropathy in the ankle of the particular F1 mice descended from two Fas-deficient strains of mice; a mutant substrain of MRL/Mp.Fas(lpr) (MRL/rpl) and C3H/He.Fas(lpr) (C3H/lpr) was recently observed.

AIM

To histopathologically characterise and genetically interpret the unique inheritance mode of disease in this arthropathy model.

METHODS

MRL/rpl, C3H/lpr, (MRL/rpl x C3H/lpr; MC) F1, (C3H/lpr x MRL/rpl; CM) F1 and MCF2 mice were bred under specific pathogen-free conditions. Histopathological grade of arthropathy was determined at 6 months by examination under a light microscope. To search for a linkage locus to the arthropathy, the whole genome of selected 48 male MCF2 mice with 71 polymorphic microsatellite markers was scanned, followed by quantitative trait locus analysis.

RESULTS

The incidence of microscopically defined arthropathy in the male and female MCF1 groups was 100% and 19.4%, respectively. No incidence was observed in the parental strains, MRL/rpl and C3H/lpr, and in CMF1 mice. In the MCF1 mice, the arthropathy mainly affected the ankle joints and was histopathologically characterised by marked entheseal proliferation with chondrocytic differentiation and ossification in the ankle joints, the manifestations similar to ankylosing enthesitis reported previously. An MRL/rpl-derived autosomal dominant susceptibility locus was mapped in the distal of D7Mit68 (60 cM) to the ankylosis onset.

CONCLUSION

The MCF1 mice stably develop spontaneous ankylosing disorders in the ankle, with a male predominance. The unique inheritance mode of ankylosis is possibly interpreted by the genetic interaction between the autosomal dominant locus and a Y-linked locus.

Teunissen-Cremers Syndrome: A Clinical, Surgical, and Genetic Report

OBJECTIVE

To describe clinical and radiologic features, results of ear surgery, and genetic analysis in three families with Teunissen-Cremers syndrome.

DESIGN

Case series.

SETTING

Tertiary referral center.

BACKGROUND

The NOG gene encodes the protein noggin, which has antagonist action in osteogenesis. Malformation of bones and joints may result from defects in noggin. Teunissen-Cremers syndrome is caused by mutations in the NOG gene. Two mutations in this gene were reported previously. The proximal symphalangism-hearing impairment syndrome, also caused by mutations in the NOG gene, is characterized by proximal symphalangism, conductive hearing loss, and occasionally synostoses.

METHODS

We examined nine affected members of three Dutch families. Reconstructive middle ear surgery was performed in five patients (nine ears), and we sequenced the NOG gene in these families.

RESULTS

Affected members had conductive hearing impairment, hyperopia, and broad thumbs and first toes with brachytelephalangia. Surgery manifested stapes ankylosis with additional incudal fixation frequently in the fossa incudis. Air-bone gaps decreased to less than 10 dB in six ears. Genetic analysis revealed three new mutations in the NOG gene.

CONCLUSION

The Teunissen-Cremers syndrome is an entity in its clinical presentation, distinct from other syndromes with proximal symphalangism and hearing impairment. So far, in five families with Teunissen-Cremers syndrome, four truncating mutations and one amino acid substitution were found in the NOG gene. The majority of other mutations found in this gene are missense mutations, which might result in some residual protein activity. Reconstructive middle ear surgery is an option for treatment.

The ANKH gene and familial calcium pyrophosphate dihydrate deposition disease

Familial calcium pyrophosphate dihydrate deposition (CPPD) disease is a chronic condition in which CPPD microcrystals deposit in the joint fluid, cartilage, and periarticular tissues. Two forms of familial CPPD disease have been identified: CCAL1 and CCAL2. The CCAL1 locus is located on the long arm of chromosome 8 and is associated with CPPD and severe osteoarthritis. The CCAL2 locus has been mapped to the short arm of chromosome 5 and identified in families from the Alsace region of France and the United Kingdom. The ANKH protein is involved in pyrophosphate metabolism and, more specifically, in pyrophosphate transport from the intracellular to the extracellular compartment. Numerous ANKH gene mutations cause familial CCAL2; they enhance ANKH protein activity, thereby elevating extracellular pyrophosphate levels and promoting the formation of pyrophosphate crystals, which produce the manifestations of the disease. Recent studies show that growth factors and cytokines can modify the expression of the normal ANKH protein. These results suggest a role for ANKH in sporadic CPPD disease and in CPPD associated with degenerative disease.

Imaging skeletal pathology in mutant mice by microcomputed tomography

OBJECTIVE

We describe the utility of microcomputed tomography ( micro CT) for imaging skeletal abnormalities in rodent model systems. For the purpose of illustration, the progressive ankylosis (ank) mutant was selected. ank mice develop prominent articular and periarticular calcifications at multiple anatomical sites, including paws, elbows, knees, and vertebrae.

METHODS

Forelimbs, hindlimbs, and proximal tail vertebrae of 4-month-old female ank/ank mice were scanned at 15 micro m resolution using a SkyScan 1072 micro CT instrument and images were generated using Analyze 4.0 software.

RESULTS

This technique was able to show, in 3-dimensional images, the abnormal calcification of ank/ank mice, which was readily observed within joint surfaces, on periosteal surfaces, sesamoid bones, menisci, and joint capsules, as well as other periarticular ligamentous structures.

CONCLUSION

As illustrated by the example of the progressive ankylosis mutant, micro CT represents a powerful emerging tool for identifying and monitoring the progression of developmental or acquired skeletal abnormalities within rodent models.

Characterization of a stapes ankylosis family with a NOG mutation

OBJECTIVE

To characterize the otologic phenotype in a family with autosomal dominant stapes ankylosis, hyperopia, and skeletal abnormalities caused by a mutation in the noggin gene (NOG).

STUDY DESIGN

Case series.

SETTING

Academic tertiary care center.

PATIENTS

Eight affected and 3 unaffected family members.

MAIN OUTCOME MEASURES

History, physical and radiologic examination, and surgical outcomes.

RESULTS

Although affected members were initially presumed to have typical nonsyndromic otosclerosis, the clinical data were most consistent with an autosomal dominant congenital stapes ankylosis syndrome. Eight of eight affected family members had bilateral low-frequency conductive hearing loss. Six of eight underwent fenestration procedures and/or stapedectomies. All members with initial postoperative closure of the air-bone gap returned to their baseline conductive loss within 2 years. Two affected family members had documented maximal conductive hearing loss by age 4, and two members without previous otologic surgery have not experienced sensorineural hearing loss. High-resolution temporal bone computed tomography showed stapes ankylosis and indistinction of the incudomalleal junction bilaterally and bony regrowth over the stapedotomy for those with stapedectomies. Detailed physical and radiologic examination identified multiple other skeletal abnormalities.

CONCLUSIONS

Although this phenotype may present as classic otosclerosis to the otolaryngologist, detailed investigation revealed a congenital stapes ankylosis syndrome. Because is essential in regulating normal bone development and maturation, mutations in this gene may be associated with excessive bony overgrowth and refixation of the stapes footplate after initial successful surgery. Patients with hereditary conductive hearing loss should be assessed to rule out subtle features of a skeletal syndrome.

Autosomal dominant stapes ankylosis with broad thumbs and toes, hyperopia, and skeletal anomalies is caused by heterozygous nonsense and frameshift mutations in NOG, the gene encoding noggin

Although fixation of the stapes is usually progressive and secondary to otosclerosis, it may present congenitally, with other skeletal manifestations, as an autosomal dominant syndrome-such as proximal symphalangism (SYM1) or multiple-synostoses syndrome (SYNS1), both of which are caused by mutations in NOG, the gene encoding noggin. We describe a family that was ascertained to have nonsyndromic otosclerosis but was subsequently found to have a congenital stapes ankylosis syndrome that included hyperopia, a hemicylindrical nose, broad thumbs and great toes, and other minor skeletal anomalies but lacked symphalangism. A heterozygous nonsense NOG mutation-c.328C-->T (Q110X), predicted to truncate the latter half of the protein-was identified, and a heterozygous insertion in NOG-c.252-253insC, in which the frameshift is predicted to result in 96 novel amino acids before premature truncation-was identified in a previously described second family with a similar phenotype. In contrast to most NOG mutations that have been reported in kindreds with SYM1 and SYNS1, the mutations observed in these families with stapes ankylosis without symphalangism are predicted to disrupt the cysteine-rich C-terminal domain. These clinical and molecular findings suggest that (1) a broader range of conductive hearing-loss phenotypes are associated with NOG mutations than had previously been recognized, (2) patients with sporadic or familial nonsyndromic otosclerosis should be evaluated for mild features of this syndrome, and (3) NOG alterations should be considered in conductive hearing loss with subtle clinical and skeletal features, even in the absence of symphalangism.

Mutations of the NOG gene in individuals with proximal symphalangism and multiple synostosis syndrome

Proximal symphalangism is an autosomal-dominant disorder with ankylosis of the proximal interphalangeal joints, carpal and tarsal bone fusion, and conductive deafness. These symptoms are shared by another disorder of joint morphogenesis, multiple synostoses syndrome. Recently, it was reported that both disorders were caused by heterozygous mutations of the human noggin gene (NOG). To date, seven mutations of NOG have been identified from unrelated families affected with joint morphogenesis. To characterize the molecular lesions of proximal symphalangism, we performed analyses of NOG in three Japanese individuals with proximal symphalangism. We found three novel mutations: g.551G>A (C184Y) in a sporadic case of symphalangism, g.386T>A (L129X) in a familial case of symphalangism, and a g.58delC (frameshift) in a family with multiple synostosis syndrome. Characteristic genotype-phenotype correlations have not been recognized from the mutations in the NOG gene.

Heterozygous mutations in ANKH, the human ortholog of the mouse progressive ankylosis gene, result in craniometaphyseal dysplasia

Craniometaphyseal dysplasia (CMD) is a bone dysplasia characterized by overgrowth and sclerosis of the craniofacial bones and abnormal modeling of the metaphyses of the tubular bones. Hyperostosis and sclerosis of the skull may lead to cranial nerve compressions resulting in hearing loss and facial palsy. An autosomal dominant form of the disorder (MIM 123000) was linked to chromosome 5p15.2-p14.1 (ref. 3) within a region harboring the human homolog (ANKH) of the mouse progressive ankylosis (ank) gene. The ANK protein spans the outer cell membrane and shuttles inorganic pyrophosphate (PPi), a major inhibitor of physiologic and pathologic calcification, bone mineralization and bone resorption. Here we carry out mutation analysis of ANKH, revealing six different mutations in eight of nine families. The mutations predict single amino acid substitutions, deletions or insertions. Using a helix prediction program, we propose for the ANK molecule 12 membrane-spanning helices with an alternate inside/out orientation and a central channel permitting the passage of PPi. The mutations occur at highly conserved amino acid residues presumed to be located in the cytosolic portion of the protein. Our results link the PPi channel ANK with bone formation and remodeling.

HLA-B27 has no effect on the phenotypic expression of progressive ankylosis in ank/ank mice

OBJECTIVE

To investigate whether HLA-B27 influences the expression of murine progressive ankylosis (MPA), a single-gene autosomal recessive mouse model of ankylosing spondylitis that arises in mice homozygous for the ank gene.

METHODS

Mice transgenic for HLA-B27 were bred with ank/ank mice, and the phenotypes of the F1 and F2 progeny were observed.

RESULTS

ank/+ mice showed no abnormalities, and ank/ank mice showed the typical phenotype of MPA, irrespective of B27 status.

CONCLUSION

HLA-B27 and the ank/ank genotype both predispose to diseases involving progressive bony ankylosis. These findings suggest that these disease processes are distinct and noninteractive, and they provide no support for the hypothesis that the human homolog of the ank locus participates in the pathogenesis of ankylosing spondylitis.

Evidence for digenic inheritance in some cases of Antley-Bixler syndrome?

The Antley-Bixler syndrome has been thought to be caused by an autosomal recessive gene. However, patients with this phenotype have been reported with a new dominant mutation at the FGFR2 locus as well as in the offspring of mothers taking the antifungal agent fluconazole during early pregnancy. In addition to the craniosynostosis and joint ankylosis which are the clinical hallmarks of the condition, many patients, especially females, have genital abnormalities. We now report abnormalities of steroid biogenesis in seven of 16 patients with an Antley-Bixler phenotype. Additionally, we identify FGFR2 mutations in seven of these 16 patients, including one patient with abnormal steroidogenesis. These findings, suggesting that some cases of Antley-Bixler syndrome are the outcome of two distinct genetic events, allow a hypothesis to be formulated under which we may explain all the differing and seemingly contradictory circumstances in which the Antley-Bixler phenotype has been recognised.

Symphalangism in children. Case report and review of the literature

Symphalangism is an uncommon syndrome characterized by fusion of the interphalangeal joints of the hands and feet. The fusion can involve the proximal or the distal joints; however, involvement of the proximal interphalangeal joints is more common. Symphalangism often is associated with several other skeletal and nonskeletal abnormalities. Analysis of the pedigrees of affected families reveals this trait to be autosomal dominant. The authors present the case of a 9-year-old boy with bilateral symphalangism of the proximal interphalangeal joints in the fingers and toes. His father is affected similarly. A comparison of these cases with those published in the literature indicates that although the radiologic appearance of symphalangism appears disabling, the fused phalanges seldom cause disability or loss of function of the hand. Surgical intervention is not required in most patients. The father and son reported also had capitellar hypoplasia and subluxation of the radial head associated with limitation of elbow flexion and extension.

A recessive mutation leading to vertebral ankylosis in zebrafish is associated with amino acid alterations in the homologue of the human membrane-associated guanylate kinase DLG3

We describe the characterization of the zebrafish homologue of the human gene DLG3. The zebrafish dlg3 gene encodes a membrane-associated guanylate kinase containing a single PDZ domain. This gene was cloned using a gene-trap construct inserted in the gene's first intron. The insertion co-segregates with a viable mutation called humpback (hmp), which leads to formation of ankylotic vertebrae in adult fishes. Insertion and mutation have both been mapped to chromosome 12, in a segment which is syntenic with region p12 to q12 of human chromosome 17. The hmp mutant phenotype, however, appears to be due to two point mutations in the guanylate kinase domain rather than to the transgene insertion itself. The results of this study are discussed in the light of the possible function of the guanylate kinase domain.

Proximal symphalangism and congenital conductive hearing loss: otologic aspects

OBJECTIVE

Results of stapedectomy are reported in a Belgian 26-year-old woman and two Dutch brothers having the proximal symphalangism syndrome (McKusick 18580).

STUDY DESIGN

Case reports are presented. A review of the results of ear surgery for congenital conductive hearing loss in this syndrome is given.

SETTING

The Belgian patient was treated in a general hospital. The Dutch patients were treated in a university hospital, which was a tertiary referral center.

PATIENTS

Patients were referred to have an evaluation of their hearing impairment.

INTERVENTION

Based on the syndromal diagnosis and based on routine audiometric tests, a congenital ossicular fixation was considered to be the cause of the hearing loss. By exploratory tympanotomies, this was confirmed. Reconstructive procedures including stapedotomy were performed.

MAIN OUTCOME MEASURES/RESULTS

Long-term audiometric data are presented to evaluate the outcome of the surgical interventions.

CONCLUSIONS

Congenital stapes ankylosis eventually combined with a congenital fixation of the short process of the incus in the fossa incudis, causing the congenital conductive hearing loss. Surgical intervention is very successful in most reported cases, but negative side effects are incidentally found as well.

Congenital stapes ankylosis, broad thumbs, and hyperopia: report of a family and refinement of a syndrome

We report on a family with conductive hearing loss due to congenital stapes ankylosis, and with hyperopia, broad thumbs, and broad first toes. Neither of the studied relatives had symphalangism, possibly distinguishing this syndrome as an entity separate from the facio-audio-symphalangism and proximal symphalangism syndromes. An alternative possibility is that this family falls within the spectrum of the facioaudio-symphalangism and proximal symphalangism syndromes. Visualization of the ossicular chain, and ophthalmologic and radiologic studies are important in the evaluation of families with congenital conductive hearing loss. A characteristic physiognomy in our patients is present; this autosomal dominant syndrome was first described by Teunissen and Cremers [1990: Laryngoscope 100:380-384].

Histopathology of murine ankylosing enthesopathy

Ankylosing enthesopathy is a spontaneously occurring progressive stiffening of the ankle and/or tarsal joints in mice of C57Black background. In C57BL/10 mice and mice of the same genetic background that had been made transgenic for HLA-B27, the start of the disease was detected by weekly testing for decreased mobility in the ankle/tarsus region. Ankylosing enthesopathy was found to begin with a short phase of proliferative inflammation of the joints and adjacent tissues, with some fibrinous exsudation, some leucocytic infiltration and slight bone erosion. This inflammation is soon accompanied and followed by proliferation of cartilaginous cells at the bone insertions of joint capsule ligaments (entheses). Ossification of the cartilage proliferations and some desmal ossification lead to large osteophytes that inhibit mobility. Fusion of osteophytes occasionally leads to marginal ankylosis. The histopathology of the successive stages of murine ankylosing enthesopathy and the preponderance in males and HLA-B27 transgenic mice are reminiscent of ankylosing spondylitis in man. The spine, however, was not affected.

The role of MHC class I heterodimer expression in mouse ankylosing enthesopathy

Ankylosing enthesopathy (ANKENT) is a spontaneous mouse joint disease with strikingly similar pathology to human HLA-B27-associated enthesopathies such as ankylosing spondylitis. In C57Bl/10 mice, transgenic HLA-B*2702 as well as H2 genes have been shown to be relative risk factors for ANKENT. To investigate the role of major histocompatibility complex (MHC) class I expression in disease pathogenesis, ANKENT occurrence was compared among beta2-microglobulin (beta2m) knockout littermates with or without transgenes for HLA-B*2702 and human beta2m. In the knockout phenotype lacking beta2m, ANKENT occurrence is significantly reduced (P = 0.016). In the absence of beta2m, B*2702 is not detected on the cell membrane, nor does it increase the risk for ANKENT. This means that the previous finding that HLA-B*2702 increases susceptibility to ANKENT in C57Bl/10 mice cannot be ascribed to a transgene insertion effect. Rather, in order to increase disease susceptibility, B*2702 must be coexpressed with mouse beta2m (mo-beta2m). In contrast, when HLA-B*2702 is expressed with beta2m of human origin, disease susceptibility is not affected. Thus, both H2(b)-derived class I heterodimers and HLA-B*2702/mo-beta2m heterodimers contribute to ANKENT susceptibility.

Murine progressive ankylosis is not immunologically mediated

OBJECTIVE

Murine progressive ankylosis is an autosomal recessive disorder in mice similar to the human spondyloarthropathies. The gene responsible for progressive ankylosis, ank, has not been identified and its product is unknown. We investigated whether the immune system plays a role in the pathogenesis of progressive ankylosis.

METHODS

Reciprocal transfers of spleen or bone marrow cells or serum between ank/ank and normal mice were performed. CD4 T cells were depleted in vivo by injection with monoclonal antibody. Ank/ank; nu/nu mice were bred from double heterozygote offspring of homozygote parents.

RESULTS

Disease was neither ameliorated nor induced by these immune system manipulations.

CONCLUSION

We conclude that progressive ankylosis is not immune mediated. The similarities between ankylosing spondylitis and murine progressive ankylosis may be due to mechanisms producing osteogenesis in nonosseous tissues.

Impairment of tooth eruption. Pathogenetic aspects

The genetically determined impairment of tooth eruption in 4 generations is analysed on the basis of an examination of 1 family, and the variability of the characteristic "tooth infraposition" is described. Starting with a 72-year-old female patient with 1 unerupted incisor, infrapositions of primary and permanent teeth in the descendants were diagnosed. We assume hereditary susceptibility resulting from a multifactorial genetic system to be the cause.

Etiopathogenesis of skeletal hyperostosis. A study of a European population that lived 7700 years ago

The prevalence of hyperostosis meeting the criteria developed by Arlet and Mazières in skeletons from two of the oldest European necropolises of neolithic farmers was about 10%, i.e., similar to that in a medieval population of comparable demographic structure. This similarity over a greater than 6600-year period suggests that hyperostosis is related to genetic factors.

Solitary caging protects mice from ankylosing enthesopathy

Murine ankylosing enthesopathy (ANKENT) is a spontaneous joint disease with numerous parallels to the human seronegative spondylarthropathies at the level of disease distribution, genetics and pathology. Although several genetic susceptibility factors have been identified previously, there is variation in disease susceptibility among genetically identical individuals, living in a stable environment. Preliminary observations indicate that males housed together with females rarely develop the disease, in contrast to males housed with other males (p < 0.25, p < 0.05, and p < 0.01). Furthermore, males caged under solitary conditions developed no ANKENT, whereas the disease did develop among individuals housed in groups of 4 (p < 0.01). The mechanism through which grouped caging induces a risk for ANKENT requires further study.

Localization of the gene (SYM1) for proximal symphalangism to human chromosome 17q21-q22

Proximal symphalangism, or Cushing symphalangism (MIM 185800), is an autosomal dominant disorder characterized by ankylosis of the proximal interphalangeal joints. Conductive deafness and reduced flexibility of the ankles have also been observed in affected individuals. We have used polymorphic markers throughout the genome to perform genetic linkage analysis in subsequent generations of the family originally described by Harvey Cushing. We have established linkage for this disorder to markers on chromosome 17 (17q21-q22), with Zmax = 6.98 at theta = 0.05 with marker D17S790.

Arthritis and ankylosis in twy mice with hereditary multiple osteochondral lesions: with special reference to calcium deposition

A murine autosomal recessive mutant named twy (tiptoe walking-Yoshimura) mouse showing multiple osteochondral lesions including ankylosis of the vertebral column and limb joints underwent sequential histopathological analysis of posterior limb joint lesions and intervertebral disc lesions. In the articular cartilage, a decrease in alcian blue-positive extracellular matrix and the presence of degenerated collagen fibers were found at the age of around 4-8 weeks. Calcium deposits in the articular cartilage were found at that time and later in the articular space and synovial tissue. Calcium deposits were also found in the intervertebral discs at 4 weeks. Using electron microscopy, some of the crystals were seen inside small vesicles. In both joints, degeneration of, and calcium deposition in, the articular cartilage progressed with age, finally producing bony ankylosis. These histological observations suggest that calcification and degeneration of the articular cartilage are the major factors in the pathogenesis of joint disorders in the twy mouse, and this mutant mouse provides a good model for studying the process and mechanism of osteoarthritic lesions, destructive arthritis and ankylosis.

Neuropathology of infant with Pena-Shokeir I syndrome

In an infant with clinical features of Pena-Shokeir I syndrome, who survived for 182 days, neuropathologic examination revealed little myelination in peripheral nerves with group atrophy of muscle fibers, dysplasia of inferior olivary and dentate nuclei, and leptomeningeal heterotopia. Congenital peripheral neuropathy associated with minor brain anomalies is characteristic in this patient, and may cause absence of fetal movements leading to ankylosis of multiple joints, absence of breathing in association with pulmonary hypoplasia, absence of swallowing causing polyhydramnios, and absence of movements of facial muscles causing craniofacial anomalies.

Secondary retention of permanent molars: a report of five families

The aetiopathogenesis of secondary retention is not fully understood, but heredity is involved in at least some cases. In this study first-degree relatives of 52 patients with secondary retention of permanent molars were screened for the presence of the same phenomenon in their dentition. Familial occurrence could be shown in five families. The pedigrees are compatible with autosomal dominant inheritance. HLA phenotypes and blood groups ABO, rhesus and P1 were studied in two families. The lod scores for linkage with secondary retention were added to previously reported information. The lod score for linkage for blood group system P increased from +0.940 to +1.475 at a recombination fraction of 5 per cent. It is concluded that secondary retention of permanent molars is an aetiologically heterogeneous condition in which some cases are caused by the presence of an abnormal autosomal dominant gene.

Distal symphalangism: a report of two families

This study describes distal symphalangism in 36 individuals in two families, one of which is the largest pedigree of this rare defect yet documented. Distal symphalangism is ankylosis or rigidity of the distal interphalangeal joints of the hands and/or feet. The findings of this report substantiate the mutation as an autosomal dominant phenotype. Several manifestations of distal symphalangism were observed, including the lack of cutaneous creases over affected joints, brachydactyly, fourth-finger hypophalangism, absent nails, and rudimentary nails. Variability ranged from just toes affected, to a single finger affected, to all fingers and all lesser toes affected. The most common expression of the mutant gene was rigid index fingers. Craniosynostosis, premature closure of the sutures of the skull, was encountered twice in the larger of the two families. It is a possible pleiotropic effect of distal symphalangism.

Congenital prearticular temporo-mandibular ankylosis in two siblings

A report of congenital ankylosis of the temporo-mandibular joint has only very rarely been published. The existence of this entity has been met with great scepticism and therefore believed to be due to perinatal trauma and subsequent development of the ankylosis. However, publications are now available of observations at birth after an uneventful pregnancy and spontaneous delivery. Our cases are the first publication of congenital TMJ ankylosis in two siblings, although there are hints in the histories in two other papers that a sibling may have suffered from the same condition. We discuss the hypothesis that the potential to ankylose in the temporomandibular area is a congenital disorder as in our cases, and that even later in life trauma or infection are only supervening initiating factors.

Progressive ankylosis (ank/ank) in mice: an animal model of spondyloarthropathy. III. Proliferative spleen cell response to T cell mitogens

Murine progressive ankylosis is a spontaneous disorder of mice resulting from a homozygous recessive genetic defect (ank/ank) which produces an inflammatory arthritis of peripheral and axial joints eventually resulting in ankylosis of these joints. This disorder resembles the human spondyloarthropathies clinically, radiographically and histologically. Various studies in humans with spondyloarthropathies have described defects of cellular immunity but these results are conflicting. We measured the spleen cell response to mitogen in ank/ank mice and in normal littermates. The spleen cell response to the T cell mitogens phytohaemagglutinin and concanavalin A was decreased in ank/ank mice compared with their normal littermates. The response to the B cell mitogen lypopolysaccharide was normal in both ank/ank mice and normal littermates. Serum from ank/ank mice did not inhibit spleen cell responses to mitogen. Ank/ank spleen cells were not inhibitory of normal spleen cell responses to mitogens. Addition of irradiated normal spleen cells to ank/ank spleen cells did not restore the mitogen responses to normal. It is possible that the ank/ank gene results in the phenotypic expression of an abnormal or decreased cell product involved in T cell proliferation. Several recently described cytokines could be potential candidates for this product.

Progressive ankylosis (ank/ank) in mice: an animal model of spondyloarthropathy. II. Light and electron microscopic findings

Murine progressive ankylosis was studied by light and electron microscopy (EM). By light microscopy, the earliest synovial lesion was inflammatory followed by synovial proliferation and cartilage erosions. Later changes included progressive joint ankylosis by fibrosis and ossification of articular and periarticular tissues and new bone proliferation. By EM, synovial cell proliferation and hypertrophy with collagen deposition was seen before the appearance of intracellular and extracellular hydroxyapatite crystals. These pathologic changes are the same as those found in the human spondyloarthropathies. Our EM findings demonstrate that hydroxyapatite crystals appear in the joints of ank/ank mice after the initial inflammatory phase.

Distal symphalangism with involvement of the thumbs and great toes

A family is presented in which five individuals in four generations have shown variable expression of distal symphalangism in hands and feet. The mode of inheritance is autosomal dominant. Two individuals show involvement of the thumbs and halluces; this has not been noted previously in true distal symphalangism.

Ankylosis in monozygotic twins

In this case report, Twin A had four teeth ankylosed and Twin B had five teeth involved; there was a nearly identical pattern of distribution and severity of ankylosis.

Hereditary joint disorder in progressive ankylosis (ank/ank) mice. II. Effect of high-dose hydrocortisone treatment on inflammation and intraarticular calcium hydroxyapatite deposits

Mice homozygous for the progressive ankylosis trait develop an inflammatory joint disorder associated with the intraarticular deposition of calcium hydroxyapatite. When affected (ank/ank) mice were treated with high doses of hydrocortisone, synovitis receded, development of cartilaginous and bony osteophytes halted, and calcium hydroxyapatite accumulated in and distended the synovial spaces. No changes, however, occurred in the joint morphology of hydrocortisone-treated normal (ank/+) mice. Since inhibition of inflammation by hydrocortisone treatment did not block apatite accumulation, intraarticular deposition of hydroxyapatite occurs independent of inflammation in progressive ankylosis.

[Intubation with the new ultra thin flexible fiberoptic scope in small children with congenital ankylosis of the temporomandibular joints]

Management of anaesthesia and intubation using a flexible endoscope of the ultra-thin generation (external diameter on the distal end 2.7 mm) of brother and sister with congenital ankylosis of the temporomandibular joint is described. Sedation was provided with ketamine while maintaining spontaneous breathing. Alternative methods to overcome difficult intubation in infants and small children with consideration of their specific anatomical conditions are discussed. Insertion of a fiberoptic endoscope through the endotracheal tube in the age group reported here was not possible hitherto. The new ultra-thin generation of flexible fiberscopes now makes it possible to perform direct fiberoptic intubation of infants and small children.

Proximal symphalangia and stapes ankylosis

A father and his two sons had an autosomal-dominant syndrome of proximal symphalangia and conductive hearing loss. Exploratory tympanotomy revealed a congenitally fixed stapes and incus in the oldest boy. Surgical intervention resulted in normal hearing. To our knowledge, this is the first such histologic report of a stapes in this syndrome.

Bilateral symphalangism of the index fingers

True symphalangism is a rigid digit of normal length. Fusion at the proximal interphalangeal joint is most common, and the index finger is the least likely to be affected. I report the second instance of true symphalangism involving fusion of the distal interphalangeal joints of both index fingers without symphalangism of any other digits. This is the first case reported in a black and was inherited as a simple Mendelian dominant trait.

Syndrome of camptodactyly, ankyloses, facial anomalies, and pulmonary hypoplasia (Pena-Shokeir syndrome): obstetric and ultrasound aspects

Two siblings with Pena-Shokeir syndrome are described. This syndrome consists of polyhydramnios, intrauterine growth retardation, short umbilical cord, perinatal death, facial abnormalities, limb abnormalities including arthrogryposis, and lethal pulmonary hypoplasia. The mode of inheritance is most likely autosomal recessive. Prenatal diagnosis was made in the second pregnancy with ultrasound performed at 26 weeks' gestation. The roles of fetal akinesia and fetal apnea in the production of the various manifestations of the syndrome are detailed, and the possibility of early prenatal diagnosis is considered.

Hereditary joint disorder in progressive ankylosis (ank/ank) mice. I. Association of calcium hydroxyapatite deposition with inflammatory arthropathy

Progressive ankylosis (ank), a murine autosomal recessive mutation, produces an inflammatory joint disorder associated with intraarticular calcium hydroxyapatite deposition and culminates in fusion of the joints. Joints in the feet become stiffened and swollen with milky white fluid containing polymorphonuclear leukocytes, large mononuclear macrophage-like cells, and calcium hydroxyapatite. The joints develop a proliferative synovitis, sometimes associated with marginal erosions of the articular cartilage and periosteal bone. Subsequently, cartilaginous osteophytes, extending outward from the subchondral bone, bridge the margins of the joint and undergo ossification. The progressive ankylosis mutation provides a useful system for investigating calcium hydroxyapatite-associated arthropathies.

The Pena-Shokeir syndrome: report of five cases and further delineation of the syndrome

We report on five cases of lethal Pena-Shokeir syndrome from three families with affected sibs. In addition to multiple anklyoses, camptodactyly, facial anomalies, and pulmonary hypoplasia, one fetus had pterygia of the neck and axillae and cardiac hypoplasia. Radiographic changes are nonspecific and probably are related to a lack of intrauterine movement. Our data and review of the literature suggest that pterygium formation is one of the manifestations of the Pena-Shokeir syndrome. A recently described lethal form of the recessively inherited multiple pterygium syndrome may represent a severe form of the Pena-Shokeir syndrome.

[Regular dominance of thumb ankylosis with mental retardation transmitted over 3 generations]

A young girl 12 old, sent to us for obesity, and coxa-epiphysiolysis showed signs of mental retardation and bilateral thumb ankylosis. The fact that the mother was also affected by both of these signs, led to a more detailed genetic research. The latter revealed that not only the daughter, the mother, but also their own mother and may be, the sister, the grand-mother and the great-aunt of the patient had a retardation, a slight dysmorphia, a type A brachydactylia, signs of obesity and an identical ankylosis of both thumbs. This vertical inheritance, affecting apparently females only, but not associated with a high rate of miscarriage, has, it seems, never been reported. The characteristics of this family are being considered and discussed.

Progressive ankylosis, a new skeletal mutation in the mouse

Progressive ankylosis, ank, a new recessive skeletal mutation causing a noninflammatory joint disease in mice is described. Preliminary observations suggest that three abnormal processes are involved: increased calcification of calcified cartilage and of joint tissues, hyperplasia of the cells and tissues of the joints, and degeneration within and around the tissues, tendons, and ligaments of the joints. The new mutation is closely linked, with about 4 percent recombination, to underwhite on chr 15.

[Subvalvular aortic stenosis, dysmorphic familial syndrome and peripheral muscular disease]

Two related cases are reported, those of two sisters aged 7 and 13, who had an aortic subvalvular stenosis in the form of a fibro-muscular channel, associated with mitral incompetence, a triangular facies with a pointed chin, pinched lips, a divergent squint, hypertelorism, a mask-like face, normal intelligence, and a peripheral muscular disorder with arthrogriposis. The description of such a combination of malformations is original, and this is discussed.