Audiological findings in otospondylomegaepiphyseal dysplasia (OSMED) associated with a novel mutation in COL11A2

Autosomal recessive otospondylo-mega-epiphyseal dysplasia: comprehensive clinical review of a pediatric cohort

Autosomal recessive otospondylo-mega-epiphyseal dysplasia (OSMEDB) is characterized by short stature with short limbs, dysmorphic facial features, and hearing loss, which is caused by biallelic, loss-of-function, variants in the COL11A2 gene. Geno-phenotypic data from the medical records of eight affected individuals from five unrelated families was abstracted, recorded in an Excel spreadsheet and analyzed using simple frequency analysis. Either short femora or short extremities with or without other ultrasonographic abnormalities were demonstrated in five patients antenatally. The mean height was -2.29 SDS. Pectus deformity, including either chest asymmetry or pectus excavatum, was present in five patients. Bilateral hearing loss was verified in all patients. Severe speech delay and learning disabilities were present in two patients whose deafness was realized after the age of 12 months. Four novel loss-of-function variants in COL11A2 were found in this cohort. We present novel geno-phenotypic findings in a pediatric cohort with OSMEDB. The age of manifestation of short stature was variable, ranging from birth to middle childhood, and the severity of short stature varied even within the same family. Hearing loss may not be evident in the neonatal period and manifest later in OSMEDB. Intermittent hearing tests should be performed for early intervention of neurolinguistic delay and learning disabilities.

Rheumatoid arthritis in a patient with compound heterozygous variants in the COL11A2 gene and progressive hearing loss: A case report

RATIONALE

Collagen type XI alpha 2 chain is a component of type XI collagen and is expressed in various tissues including articular cartilage and tectorial membrane of the cochlea. Variants in the COL11A2 gene, which encodes collagen type XI alpha 2 chain, has been reported to cause hearing loss and has been associated with osteoarthritis and ossification of the posterior longitudinal ligament of the spine. Despite the importance of type XI collagen in the joints, association of rheumatoid arthritis (RA) with COL11A2 has not been reported.

PATIENT CONCERNS

The patient is a 60-year-old female, born to Japanese parents of no known consanguinity. She had progressive hearing loss since childhood. Her father also had progressive hearing loss before middle age. She developed joint pain in the knees and the hips in her forties. When she was 56, she developed polyarthritis. Rheumatoid factor and anti-CCP antibodies were positive.

DIAGNOSES

She was diagnosed with osteoarthritis and RA. Whole exome analysis detected 2 rare variants, c.4201C>T, p.(Arg1401Trp) and c4265C>T, p.(Pro1422Leu), in the COL11A2 gene (NM_080680.2). Whole genome analysis with a long insert size confirmed 2 variants that are in trans.

INTERVENTIONS AND OUTCOMES

She received a cochlear implant, which improved her hearing. She was treated with methotrexate, golimumab, tocilizumab, and upadacitinib with partial responses for her RA.

LESSONS

We herein report a patient with RA with compound heterozygous variants in the COL11A2 gene. Autoantibodies against type XI collagen are detected in the sera of patients with RA, suggesting the possibility that type XI collagen may be involved in the pathogenesis of RA as an autoantigen. The hearing loss and osteoarthritis in this patient may be due to the compound heterozygous variants in the COL11A2 gene, and the conformational changes induced by the variants may have changed the immunogenicity of type XI collagen, leading to the development of RA.

Otospondylomegaepiphyseal Dysplasia: A Case Report of Clinical and Radiographic Findings

CASE

We present a long-term follow-up on a woman with otospondylomegaepiphyseal dysplasia (OSMED). At the age of 46 years, she is one of the oldest patients with the syndrome in the literature to date. We focus on the musculoskeletal anatomy and orthopaedic interventions over her lifetime.

CONCLUSION

OSMED is a very rare syndrome. Arthritis and joint pains presented in her early adolescence and progressed to the point of requiring joint replacements by her 20s. Early intervention and monitoring improved the quality of life for this patient.

Genetic variant of COL11A2 gene is functionally associated with developmental dysplasia of the hip in Chinese Han population

OBJECTIVES

Developmental dysplasia of the hip (DDH) is a common skeletal disorder. This study was conducted to demonstrate the association between DDH and a polymorphism rs9277935 of COL11A2 gene.

RESULTS

A significant difference in genotype distribution in a recessive model (TT+GT vs. GG) between two groups (P=0.017) was demonstrated. Analysis in female patients showed significantly greater frequency of minor allele G(0.49 vs. 0.43, p=0.024) and significantly higher distribution of GG genotype (p=0.006). DDH patients were found to have significantly lower COL11A2 expression than controls. Moreover, DDH patients with rs9277935 genotype TT have a significantly increased expression of COL11A2 than those with genotype GG. COL11A2 demonstrated chondrogenic properties in vitro.

CONCLUSION

Polymorphism rs9277935 of gene COL11A2 is a functional variant regulating the expression and the chondrogenic properties of COL11A2 in DDH in Chinese Han population.

METHODS

A case-control candidate gene association study was conducted in 945 patients (350 radiologically confirmed DDH patients and 595 healthy controls). Difference of COL11A2 expression in hip joint tissue was compared between the patients and the controls. Allelic difference in Col11a2 expression by rs9277935 was assessed with luciferase activity. Chondrogenic effects of Col11a2 signaling on BMSCs were also determined in vitro.

Dual Diagnosis of Ellis-van Creveld Syndrome and Hearing Loss in a Consanguineous Family

Multilocus analysis of rare or genetically heterogeneous diseases is a distinct advantage of next-generation sequencing (NGS) over conventional single-gene investigations. Recent studies have begun to uncover an under-recognized prevalence of dual molecular diagnoses in patients with a "blended" phenotype that is the result of 2 clinical diagnoses involving 2 separate genetic loci. This blended phenotype could be mistakenly interpreted as a novel clinical extension of a single-gene disorder. In this study, we ascertained a proband from a large consanguineous Iranian family who manifests postlingual, progressive, moderate hearing loss in addition to suspected Ellis-van Creveld syndrome phenotype. NGS with a customized skeletal dysplasia panel containing over 370 genes and subsequent bioinformatics analysis disclosed 2 homozygous mutations in EVC2 (c.2653C>T; p.Arg885*) and COL11A2 (c.966dup; p.Thr323Hisfs*19), respectively. This study highlights a dual molecular diagnosis in a patient with a blending of 2 distinct phenotypes and illustrates the advantage and importance of this staple technology to facilitate rapid and comprehensive genetic dissection of a heterogeneous phenotype. The differentiation between phenotypic expansion of a genetic disorder and a blended phenotype that is due to more than one distinct genetic aberration is essential in order to reduce the diagnostic odyssey endured by patients.

Molecular genetics of the COL2A1-related disorders

Type II collagen, comprised of three identical alpha-1(II) chains, is the major collagen synthesized by chondrocytes, and is found in articular cartilage, vitreous humour, inner ear and nucleus pulposus. Mutations in the collagen type II alpha-1 gene (COL2A1) have been reported to be responsible for a series of abnormalities, known as type II collagenopathies. To date, 16 definite disorders, inherited in an autosomal dominant or recessive pattern, have been described to be associated with the COL2A1 mutations, and at least 405 mutations ranging from point mutations to complex rearrangements have been reported, though the underlying pathogenesis remains unclear. Significant clinical heterogeneity has been reported in COL2A1-associated type II collagenopathies. In this review, we highlight current knowledge of known mutations in the COL2A1 gene for these disorders, as well as genetic animal models related to the COL2A1 gene, which may help us understand the nature of complex phenotypes and underlying pathogenesis of these conditions.

Non-ocular Stickler syndrome with a novel mutation in COL11A2 diagnosed by massively parallel sequencing in Japanese hearing loss patients

OBJECTIVES

This study aims to document the clinical features of patients with COL11A2 mutations and to describe the usefulness of massively parallel sequencing.

METHODS

One thousand one hundred twenty (1120) Japanese hearing loss patients from 53 ENT departments nationwide participated in this study. Massively parallel sequencing of 63 genes implicated in hearing loss was performed to identify the genetic causes in the Japanese hearing loss patients.

RESULTS

A novel mutation in COL11A2 (c.3937_3948delCCCCCAGGGCCA) was detected in an affected family, and it was segregated in all hearing loss individuals. The clinical findings of this family were compatible with non-ocular Stickler syndrome. Orofacial features of mid-facial hypoplasia and slowly progressive mild to moderate hearing loss were also presented. Audiological examinations showed favorable auditory performance with hearing aid(s).

CONCLUSION

This is the first case report of the genetic diagnosis of a non-ocular Stickler syndrome family in the Japanese population. We suggest that it is important to take both genetic analysis data and clinical symptoms into consideration to make an accurate diagnosis.

Novel mutations confirm that COL11A2 is responsible for autosomal recessive non-syndromic hearing loss DFNB53

Hearing loss (HL) is a major public health issue. It is clinically and genetically heterogeneous.The identification of the causal mutation is important for early diagnosis, clinical follow-up, and genetic counseling. HL due to mutations in COL11A2, encoding collagen type XI alpha-2, can be non-syndromic autosomal-dominant or autosomal-recessive, and also syndromic as in Otospondylomegaepiphyseal Dysplasia, Stickler syndrome type III, and Weissenbacher-Zweymuller syndrome. However, thus far only one mutation co-segregating with autosomal recessive non-syndromic hearing loss (ARNSHL) in a single family has been reported. In this study, whole exome sequencing of two consanguineous families with ARNSHL from Tunisia and Turkey revealed two novel causative COL11A2 mutations, c.109G > T (p.Ala37Ser) and c.2662C > A (p.Pro888Thr). The variants identified co-segregated with deafness in both families. All homozygous individuals in those families had early onset profound hearing loss across all frequencies without syndromic findings. The variants are predicted to be damaging the protein function. The p.Pro888Thr mutation affects a -Gly-X-Y- triplet repeat motif. The novel p.Ala37Ser is the first missense mutation located in the NC4 domain of the COL11A2 protein. Structural model suggests that this mutation will likely obliterate, or at least partially compromise, the ability of NC4 domain to interact with its cognate ligands. In conclusion, we confirm that COL11A2 mutations cause ARNSHL and broaden the mutation spectrum that may shed new light on genotype-phenotype correlation for the associated phenotypes and clinical follow-up.