Stickler Syndrome: A Review of Clinical Manifestations and the Genetics Evaluation

Pathogenic Gene Variants Identified in Patients Presenting With Perthes or Perthes-like Hip Disorder

AIMS

Legg-Calve-Perthes disease (LCPD) is a diagnosis of exclusion. Various conditions, such as skeletal dysplasias, can closely mimic LCPD and these must be ruled out to provide appropriate treatment, prognosis, and counseling. Traditionally, genetic testing has not been readily available in pediatric orthopaedic practice. Furthermore, the clinical value of genetic testing patients with LCPD is unclear. With the advance of next-generation sequencing (NGS) technology, genetic testing has become clinically available as a lab test. The purposes of this study were to assess the clinical utility of genetic testing in select patients with LCPD and to determine the patient characteristics of those who tested positive for skeletal dysplasia.

METHODS

This is an IRB-approved, retrospective study of 63 consecutive patients who presented with Perthes-like symptoms and/or x-ray findings and who had genetic testing. The reason(s) for genetic testing included bilateral hip disease, family history of LCPD, short stature, suspected skeletal dysplasia, atypical radiographic findings, and/or combinations of these reasons.

RESULTS

Of the 63 patients, 19 patients (30%) were found to have a pathogenic gene variant. In 8 of the 19, a variety of skeletal dysplasia was diagnosed. The remaining 11 patients were found to be carriers of autosomal recessive disorders. All 19 patients were referred for genetic counseling. Of the 8 patients found to have skeletal dysplasia, 3 had bilateral disease, 3 were <10 percentile in height, 1 had a family history of "LCPD," and 3 had atypical x-ray findings. In addition to the pathogenic variants, numerous genetic variants of unknown significance were found with 2 gene variants showing exactly the same variant found in 2 unrelated patients.

CONCLUSIONS

With 30% of the patients showing pathogenic results, genetic testing of select patients with Perthes-like disease is valuable in detecting an underlying genetic disorder or a carrier status of a genetic disorder.

Identification and functional characteristics of a novel splicing heterozygote variant of COL2A1 associated with Stickler syndrome type I

Background

Stickler syndrome type I (STL1) is an autosomal dominant disorder characterized by ocular, auditory, orofacial, and skeletal anomalies. The main causes of STL1 are variants in the COL2A1 gene, which encodes a type II collagen precursor protein. The specific focus of this study was on a newborn from China diagnosed with STL1, with the aim of providing novel insights into the effects of a newly identified intronic variant in the COL2A1 gene on pre-mRNA splicing.

Methods

Trio whole exome sequencing was used to identify the causative variant in the family. The identified variant was validated using Sanger sequencing. Bioinformatics programs were used to predict the pathogenicity of the candidate variant. Additionally, an in vitro minigene assay was used to investigate the effects of the identified variant on RNA splicing.

Results

The proband with STL1 had a novel heterozygous splicing variant in the intron nine acceptor donor site of COL2A1 (c.655-2A>G). This splice junction variant resulted in aberrant COL2A1 mRNA splicing, leading to the skipping of exon 10 and the production of a shorter protein that may lack the last 18 native amino acids.

Conclusion

The c.655-2A>G variant in the COL2A1 gene leads to STL1 through abnormal splicing. By expanding the spectrum of variants in the COL2A1 gene, this finding improves the clinical understanding of STL1 and provides guidance for early diagnosis and disease counseling.

Outcomes of rhegmatogenous retinal detachment surgery in patients with Stickler syndrome

PURPOSE

Despite recent developments in vitrectomy technology and instrumentation, rhegmatogenous retinal detachment in Stickler syndrome (RDS) remains a challenge for surgeons. RDSs are associated with a higher rate of complications and surgical failures than those not associated with Stickler syndrome. This study is a report about anatomic and visual outcomes of RDS surgery and describes the surgical techniques associated with the treatment of this specific condition.

METHODS

This is a retrospective, interventional, consecutive case series of patients with RDS undergoing retinal reattachment surgery from 1990 to 2020 at the Institute of Ocular Microsurgery (IMO) in Barcelona, Spain.

RESULTS

Twenty-four eyes of 18 patients with genetically confirmed Stickler syndrome were included in the study. Ten eyes (41.6%) presented a giant retinal tear. Retinal reattachment was achieved in all cases after an average of 1.21 (range 1-6) surgical interventions. Nineteen eyes (79%) required only one operation to achieve complete retinal reattachment. The most common first surgical procedure was a 4-mm scleral buckle with posterior pars plana vitrectomy and silicone oil endotamponade, performed on 16 (66.6%) of the eyes. The mean follow-up period was 10.2 years. Mean preoperative visual acuity LogMar was 1.10 (Snellen equivalent 20/252), which improved to 0.50 (Snellen equivalent 20/63) at final follow-up (p < 0.05).

CONCLUSION

In most RDS cases, anatomic success and visual acuity improvement can be achieved with the first surgical procedure, using a combination of silicone oil tamponade and a 4-mm scleral encircling band. In some early cases of RDS, other less invasive surgical techniques can be used.

The titers of antinuclear antibodies are associated with the degree of inflammation and organ damage in Primary Sjögren's Syndrome

Primary Sjögren's Syndrome (pSS) falls within the category of connective tissue diseases, characterized by the presence of autoantibodies such as antinuclear antibodies (ANA). However, according to the classification criteria for pSS, some patients may exhibit a negative result for autoantibodies. Patients with a negative result for autoantibodies may lack typical features of connective tissue diseases, and the immunological state as well as the extent of organ involvement and damage may differ from those with positive autoantibodies. This study aims to compare the clinical phenotypes of patients with positive and negative autoantibodies, providing insights for disease classification and treatment selection for clinicians. Patients with pSS were grouped based on the presence and titers of their autoantibodies. Subsequently, differences in organ damage and laboratory indicators were compared between these groups, aiming to analyze the value of autoantibody titers in assessing the condition of pSS. (1) Patients with positive ANA exhibited elevated levels of inflammatory indicators, including ESR, IgG levels, lip gland biopsy pathology grade, and overall organ involvement, in comparison with patients with negative ANA (P < 0.05). Furthermore, ANA-positivity correlated with a higher occurrence of multi-organ damage, particularly affecting the skin, mucous membranes, and the hematological system (P < 0.05). (2) As ANA titers increased, patients demonstrated elevated levels of IgG and an escalation in organ involvement (P < 0.05). (3) Patients in the positive autoantibody group (positive for antinuclear antibodies, anti-SSA, or anti-SSB antibodies) had higher IgG levels compared to the negative group (P < 0.05). (4) Patients with positive anti-SSA and anti-SSB antibodies exhibited higher levels of inflammatory indicators and IgG compared to other patients (P < 0.05); however, no significant differences were observed in terms of organ involvement and organ damage. Patients with positive ANA in pSS typically exhibit higher levels of inflammation and an increased likelihood of experiencing multi-organ damage. Furthermore, as the ANA titers increase, both inflammation levels and the risk of multi-organ damage also escalate. Additionally, the presence of anti-SSA and anti-SSB antibodies may contribute to an elevated risk of increased inflammation levels, but does not increase the risk of organ damage.

Nonperfusion of the Far Peripheral Retina in Highly Myopic Stickler Syndrome

Purpose: To describe the clinical course of 3 patients with Stickler syndrome found on fluorescein angiography (FA) to have nonperfusion of the peripheral retina. Methods: Three patients with confirmed Stickler syndrome were examined under anesthesia. Genetic testing and FA were performed. Results: Each patient had characteristic ocular findings of Stickler syndrome, including high myopia with vitreoretinal degeneration. FA was performed on each patient and showed 360 degrees of nonperfusion of the retinal periphery in all eyes, with mild leakage in Case 3. Conclusions: The current series presents evidence of peripheral retinal nonperfusion in 3 consecutive patients with Stickler syndrome. Based on these findings, the authors recommend adopting FA as a standard imaging modality and using laser photocoagulation to treat the areas of retinal nonperfusion for all patients with Stickler syndrome.

Unraveling the genetic collagen connection: clinical and therapeutic insights on genetic connective tissue disorders

Hereditary connective tissue disorders include more than 200 conditions affecting different organs and tissues, compromising the biological role of the extracellular matrix through interference in the synthesis, development, or secretion of collagen and/or its associated proteins. The clinical phenotype includes multiple signs and symptoms, usually nonspecific but of interest to rheumatologists because of musculoskeletal involvement. The patient´s journey to diagnosis is long, and physicians should include these disorders in their differential diagnoses of diseases with systemic involvement. In this review, insights for the diagnosis and treatment of osteogenesis imperfecta, hypermobility spectrum disorder/Ehlers-Danlos syndrome, Marfan, Loeys-Dietz, and Stickler syndromes are presented.

Retinal detachment with multiple macrocysts in Stickler syndrome: case report and review of the literature

Background

Stickler syndrome is a hereditary connective tissue disorder associated with ocular, orofacial, musculoskeletal, and auditory impairments. Its main clinical characteristics include retinal detachment, hearing loss, and midface underdevelopment. In clinical practice, macrocyst is rarely reported in retinal detachment cases with Stickler syndrome.

Case presentation

We report the case of a 7-year-old child who developed a rhegmatogenous retinal detachment (RRD) in the right eye, accompanied by multiple peripheral macrocysts. The detachment was successfully surgically repaired with vitrectomy, retinal laser photocoagulation, cryotherapy and silicone oil tamponade. During the operation, a mini-retinectomy in the outer layer of each macrocyst was made for vesicular drainage and retinal reattachment. Genetic testing identified a pathogenic point mutation variant (c.1693C>T; p.Arg565Cys) in exon 26 of the COL2A1 gene. Six-months after the operation, the retina remained attached with improvement of best corrected visual acuity to 20/200.

Conclusion

Patients with Stickler syndrome may develop RRD of different severity. Macrocyst is rarely reported in previous literature of Stickler syndrome. In this case report, we share our experience in treating with multiple macrocysts in RRD and emphasize the importance of periodic follow-up for patients with Stickler syndrome.

Glycosylation Modulates the Structure and Functions of Collagen: A Review

Collagens are fundamental constituents of the extracellular matrix and are the most abundant proteins in mammals. Collagens belong to the family of fibrous or fiber-forming proteins that self-assemble into fibrils that define their mechanical properties and biological functions. Up to now, 28 members of the collagen superfamily have been recognized. Collagen biosynthesis occurs in the endoplasmic reticulum, where specific post-translational modification-glycosylation-is also carried out. The glycosylation of collagens is very specific and adds β-d-galactopyranose and β-d-Glcp-(1→2)-d-Galp disaccharide through β-O-linkage to hydroxylysine. Several glycosyltransferases, namely COLGALT1, COLGALT2, LH3, and PGGHG glucosidase, were associated the with glycosylation of collagens, and recently, the crystal structure of LH3 has been solved. Although not fully understood, it is clear that the glycosylation of collagens influences collagen secretion and the alignment of collagen fibrils. A growing body of evidence also associates the glycosylation of collagen with its functions and various human diseases. Recent progress in understanding collagen glycosylation allows for the exploitation of its therapeutic potential and the discovery of new agents. This review will discuss the relevant contributions to understanding the glycosylation of collagens. Then, glycosyltransferases involved in collagen glycosylation, their structure, and catalytic mechanism will be surveyed. Furthermore, the involvement of glycosylation in collagen functions and collagen glycosylation-related diseases will be discussed.

Multidisciplinary approach to inherited causes of dual sensory impairment

PURPOSE

This article presents a review of the main causes of inherited dual sensory impairment (DSI) with an emphasis on the multidisciplinary approach.

METHODS

A narrative review of English literature published before January 2023 was conducted using PubMed, Medline, and Scopus databases. The different causes of inherited DSI are discussed from a multidisciplinary perspective.

RESULTS

There are a wide range of dual sensory impairment (DSI), commonly referred to as blindness and deafness. While Usher syndrome is the most frequent genetic cause, other genetic syndromes such as Alport syndrome or Stickler syndrome can also lead to DSI. Various retinal phenotypes, including pigmentary retinopathy as seen in Usher syndrome, vitreoretinopathy as in Stickler syndrome, and macular dystrophy as in Alport syndrome, along with type of hearing loss (sensorineural or conductive) and additional systemic symptoms can aid in diagnostic suspicion. A thorough ophthalmologic and otorhinolaryngologic examination can help guide diagnosis, which can then be confirmed with genetic studies, crucial for determining prognosis. Effective hearing rehabilitation measures, such as hearing implants, and visual rehabilitation measures, such as low vision optical devices, are crucial for maintaining social interaction and proper development in these patients.

CONCLUSIONS

While Usher syndrome is the primary cause of inherited dual sensory impairment (DSI), other genetic syndromes can also lead to this condition. A proper diagnostic approach based on retinal phenotypes and types of hearing loss can aid in ruling out alternative causes. Multidisciplinary approaches can assist in reaching a definitive diagnosis, which has significant prognostic implications.

The Incidence of Velopharyngeal Insufficiency in Stickler Syndrome

OBJECTIVE

Stickler Syndrome (SS) is an inherited collagenopathy characterized by heterogenous orofacial, ocular, auditory, and skeletal abnormalities. The orofacial manifestations are variable and some patients present with cleft palate and velopharyngeal insufficiency (VPI). The incidence of VPI in SS is poorly studied and no studies have compared the incidence of VPI between Type I (COL2A1) and Type II (COL11A1) SS. The objective of this study is to compare the incidence of VPI between SS subtypes and discuss the surgical techniques used to treat them.

DESIGN

Single-institution, retrospective chart review.

SETTING

Tertiary pediatric hospital.

PATIENTS/PARTICIPANTS

Forty-three children were diagnosed with SS between January 2003 and December 2018. Genetic testing results, genetics notes, craniofacial clinic notes, and operative reports were reviewed. Patients without genetic testing or craniofacial/otolaryngologic evaluation were excluded. Thirty-one patients met criteria and were included.

MAIN OUTCOME MEASURE

Primary outcome was VPI incidence.

RESULTS

There were 18 patients with Type I SS and 13 with Type II SS. Five (16%) patients had VPI, 2 (11%) with Type I SS compared to 3 (23%) with Type II SS (P > .05). All patients with VPI underwent surgery with either sphincter pharyngoplasty (3) or pharyngeal flap (2). Two patients with Type II SS underwent revision sphincter pharyngoplasty, with one conversion to pharyngeal flap.

CONCLUSION

VPI is common for patients with SS. In this study, there was no significant difference in the incidence of VPI between SS subtypes. Future studies are needed to confirm these findings, which could be important for patient counseling and treatment planning.

Pierre Robin sequence coexisting with ectopic kidney, bilateral developmental hip dysplasia in a child - A rare case report

Pierre Robin sequence is a rare congenital disorder with variable associations. A two-year-old female child was brought in with complaints of an abnormal gait and right lower limb shortening. A comprehensive clinical evaluation unveiled facial characteristics resembling those of Pierre Robin Sequence, including micrognathia, a cleft palate, and glossoptosis. The child also exhibited retrognathia, a low posterior hairline, bilateral developmental dysplasia of the hips, right foot syndactyly, and a left ectopic kidney as confirmed by ultrasonography. Radiological examination showed bilateral developmental dysplastic hips. The connection between Pierre Robin sequence and the presence of bilateral dysplastic hips and an ectopic kidney is an unusual and rare combination.

The genetics and disease mechanisms of rhegmatogenous retinal detachment

Rhegmatogenous retinal detachment (RRD) is a sight threatening condition that warrants immediate surgical intervention. To date, 29 genes have been associated with monogenic disorders involving RRD. In addition, RRD can occur as a multifactorial disease through a combined effect of multiple genetic variants and non-genetic risk factors. In this review, we provide a comprehensive overview of the spectrum of hereditary disorders involving RRD. We discuss genotype-phenotype correlations of these monogenic disorders, and describe genetic variants associated with RRD through multifactorial inheritance. Furthermore, we evaluate our current understanding of the molecular disease mechanisms of RRD-associated genetic variants on collagen proteins, proteoglycan versican, and the TGF-β pathway. Finally, we review the role of genetics in patient management and prevention of RRD. We provide recommendations for genetic testing and prophylaxis of at-risk patients, and hypothesize on novel therapeutic approaches beyond surgical intervention.

Axial length shortening in myopic children with Stickler syndrome after repeated low-level red-light therapy

AIM

To report the myopia-controlling effect of repeated low-level red-light (RLRL) therapy in patients with Stickler syndrome (STL), an inherited collagenic disease typically presenting with early onset myopia.

METHODS

Three STL children, aged 3, 7, and 11y, received RLRL therapy throughout the follow-up period of 17, 3, and 6mo, respectively after exclusion of fundus anomalies. Data on best-corrected visual acuity (BCVA), intraocular pressure, cycloplegic subjective refraction, ocular biometrics, scanning laser ophthalmoscope, optical coherence tomography, genetic testing, systemic disease history, and family history were recorded.

RESULTS

At the initiation of the RLRL therapy, the spherical equivalent (SE) of 6 eyes from 3 patients ranged from -3.75 to -20.38 D, axial length (AL) were from 23.88 to 30.68 mm, and BCVA were from 0.4 to 1.0 (decimal notation). Myopia progression of all six eyes slowed down after RLRL therapy. AL in five out of the six eyes shortened -0.07 to -0.63 mm. No side effects were observed.

CONCLUSION

Three cases of STL whose progression of myopic shift and AL elongation are successfully reduced and even reversed after RLRL therapy.

Inherited causes of combined vision and hearing loss: clinical features and molecular genetics

Combined vision and hearing loss, also known as dual sensory impairment, can occur in several genetic conditions, including ciliopathies such as Usher and Bardet-Biedl syndrome, mitochondrial DNA disorders and systemic diseases, such as CHARGE, Stickler, Waardenburg, Alport and Alstrom syndrome. The retinal phenotype may point to the diagnosis of such disorders. Herein, we aim to provide a comprehensive review of the molecular genetics and clinical features of the most common non-chromosomal inherited disorders to cause dual sensory impairment.

Venous Tortuosity in COL4A2-Associated Gould Syndrome

Mutations in collagen-encoding genes have been linked to numerous systemic diseases. Specifically, pathologic alterations in COL4A2 have been linked to Gould syndrome, a hereditary angiopathy affecting the brain, kidneys, and eyes. However, the ocular phenotype associated with COL4A2-associated disease has yet to be fully characterized. In this report, we describe a novel variant in COL4A2 identified in a 48-year-old woman and her 15-year-old daughter. Funduscopic examination demonstrated significant venous and arteriolar tortuosity. Genetic testing revealed a novel variant, c.2321G>A:p.(Gly774Glu), in COL4A2. This vascular phenotype is similar to the familial retinal arterial tortuosity seen in COL4A2-associated Gould syndrome with additional venous involvement. [Ophthalmic Surg Lasers Imaging Retina 2023;54:536-539.].

Marfan Syndrome: Enhanced Diagnostic Tools and Follow-up Management Strategies

Marfan syndrome (MFS) is a rare inherited autosomic disorder, which encompasses a variety of systemic manifestations caused by mutations in the Fibrillin-1 encoding gene (FBN1). Cardinal clinical phenotypes of MFS are highly variable in terms of severity, and commonly involve cardiovascular, ocular, and musculoskeletal systems with a wide range of manifestations, such as ascending aorta aneurysms and dissection, mitral valve prolapse, ectopia lentis and long bone overgrowth, respectively. Of note, an accurate and prompt diagnosis is pivotal in order to provide the best treatment to the patients as early as possible. To date, the diagnosis of the syndrome has relied upon a systemic score calculation as well as DNA mutation identification. The aim of this review is to summarize the latest MFS evidence regarding the definition, differences and similarities with other connective tissue pathologies with severe systemic phenotypes (e.g., Autosomal dominant Weill-Marchesani syndrome, Loeys-Dietz syndrome, Ehlers-Danlos syndrome) and clinical assessment. In this regard, the management of MFS requires a multidisciplinary team in order to accurately control the evolution of the most severe and potentially life-threatening complications. Based on recent findings in the literature and our clinical experience, we propose a multidisciplinary approach involving specialists in different clinical fields (i.e., cardiologists, surgeons, ophthalmologists, orthopedics, pneumologists, neurologists, endocrinologists, geneticists, and psychologists) to comprehensively characterize, treat, and manage MFS patients with a personalized medicine approach.

Variants of LRP2, encoding a multifunctional cell-surface endocytic receptor, associated with hearing loss and retinal dystrophy

Hereditary deafness and retinal dystrophy are each genetically heterogenous and clinically variable. Three small unrelated families segregating the combination of deafness and retinal dystrophy were studied by exome sequencing (ES). The proband of Family 1 was found to be compound heterozygous for NM_004525.3: LRP2: c.5005A > G, p.(Asn1669Asp) and c.149C > G, p.(Thr50Ser). In Family 2, two sisters were found to be compound heterozygous for LRP2 variants, p.(Tyr3933Cys) and an experimentally confirmed c.7715 + 3A > T consensus splice-altering variant. In Family 3, the proband is compound heterozygous for a consensus donor splice site variant LRP2: c.8452_8452 + 1del and p.(Cys3150Tyr). In mouse cochlea, Lrp2 is expressed abundantly in the stria vascularis marginal cells demonstrated by smFISH, single-cell and single-nucleus RNAseq, suggesting that a deficiency of LRP2 may compromise the endocochlear potential, which is required for hearing. LRP2 variants have been associated with Donnai-Barrow syndrome and other multisystem pleiotropic phenotypes different from the phenotypes of the four cases reported herein. Our data expand the phenotypic spectrum associated with pathogenic variants in LRP2 warranting their consideration in individuals with a combination of hereditary hearing loss and retinal dystrophy.

Streptococcal pyomyositis in asplenia and underlying connective tissue disease

Pyomyositis is an infection of skeletal muscles, commonly affecting deep longitudinal muscles of the lower extremities. Primary pyomyositis is uncommon in the United States. Staphylococcus aureus is the most common cause of pyomyositis, but Streptococcus pneumoniae is the most common cause of life-threatening bacterial infection in asplenic patients. Most cases of S. pneumoniae pyomyositis occur in immunocompromised patients. We describe a 31-year-old man with S. pneumoniae pyomyositis whose diagnosis and hospital course were complicated by an immunocompromised state from asplenia and an underlying connective tissue disease, Stickler syndrome. Underlying connective tissue diseases such as systemic lupus erythematosus and polymyositis can predispose patients to infection, but susceptibility with Stickler syndrome is less known. While pyomyositis is only seen in up to 0.2% of US hospital admissions, it remains a pertinent differential for patients with asplenia and connective tissue disease.

Characteristics of a Three-Generation Family with Stickler Syndrome Type I Carrying Two Different COL2A1 Mutations

Stickler Syndrome is typically characterized by ophthalmic manifestations including vitreous degeneration and axial lengthening that predispose to retinal detachment. Systemic findings consist of micrognathia, cleft palate, sensorineural hearing loss, and joint abnormalities. COL2A1 mutations are the most common, however, there is a lack of genotype-phenotype correlations. Retrospective, single-center case series of a three-generation family. Clinical features, surgical requirements, systemic manifestations, and genetic evaluations were collected. Eight individuals clinically displayed Stickler Syndrome, seven of whom had genetic confirmation, and two different COL2A1 mutations (c.3641delC and c.3853G>T) were identified. Both mutations affect exon 51, but display distinct phenotypes. The c.3641delC frameshift mutation resulted in high myopia and associated vitreous and retinal findings. Individuals with the c.3853G>T missense mutation exhibited joint abnormalities, but mild ocular manifestations. One individual in the third generation was biallelic heterozygous for both COL2A1 mutations and showed ocular and joint findings in addition to autism and severe developmental delay. These COL2A1 mutations exhibited distinct eye vs. joint manifestations. The molecular basis for these phenotypic differences remains unknown and demonstrates the need for deep phenotyping in patients with Stickler syndrome to correlate COL2A1 gene function and expression with ocular and systemic findings.

Progressive degeneration of the retina in Loxl3 mutant mouse model of Stickler syndrome

Stickler syndrome is a multisystem collagenopathy with affected individuals exhibiting a high rate of ocular complications. Lysyl oxidase-like 3 (LOXL3) is a human disease gene candidate with a critical role in catalyzing collagen crosslinking. A homozygous missense variant of LOXL3 was reported in Stickler syndrome with severe myopia. However, the underlying mechanisms of the LOXL3 missense mutation that causes Stickler syndrome are unknown. In this study, a mouse model of Stickler syndrome induced by LOXL3 mutation (c.2027G ​> ​A, p.Cys676Try) was obtained using CRISPR/Cas9 gene editing techniques. The Loxl3 mutant mice exhibited perinatal death, spinal deformity, and cleft palate, and Loxl3 mutation also induced skeletal dysplasia and progressive visual degeneration. Furthermore, we observed the damage of the bruch's membrane (BrM) and an increase in the levels of glial fibrillary acidic protein (GFAP) and Rpe65 in the Loxl3 mutant mice. Thus, we provided the critical in vivo evidence that Loxl3 possibly has a pivotal role in maintaining the eye function.

Retinal Detachment Prophylaxis for Patients With Stickler Syndrome: A Survey of Pediatric Retinal Specialist Treatment Preferences

BACKGROUND AND OBJECTIVE

Stickler syndrome is the most common inherited cause of pediatric rhegmatogenous retinal detachment. The purpose of this study was to survey pediatric retinal surgeon preferences for prophylactic treatment of Stickler syndrome patients.

STUDY DESIGN

A voluntary, anonymous 27-question survey was developed by RedCap and distributed to the Association of Pediatric Retinal Surgeons. The survey was distributed on March 17, 2021. Results were tabulated on April 12, 2021 in Microsoft Excel. All surveys returned were included.

RESULTS

Thirty-four (76% response rate) respondents completed the survey. Twenty-six (76%) reported primarily using prophylactic laser retinopexy, four (12%) preferred use of cryotherapy, and 12% reported using prophylactic scleral buckle.

CONCLUSIONS

The majority of the United States. and international pediatric retinal surgeons use laser retinopexy as the primary method of prophylactic treatment. These results may serve as a benchmark for retinal surgeons less familiar with prophylactic treatment approaches. [Ophthalmic Surg Lasers Imaging Retina 2023;54:102-107.].

Long-term anatomical and functional outcomes of surgical treatment of retinal complications in children and adolescents with Stickler syndrome between 2004 and 2021

BACKGROUND

Stickler syndrome (STL) is an inherited progressive connective tissue collagen disorder. STL is the most common hereditary cause of retinal complications, retinal tears, and the development of retinal detachment (RD) in childhood. The aim of the study was to evaluate the long-term anatomical and functional results of surgical treatment of retinal complications in children and adolescents affected by STL.

METHODS

A retrospective, single-center study was performed a cohort of children with STL who underwent retinal surgery between 2004 and 2021.

RESULTS

The study group consisted of nine children; the mean age at the time of the retinal tear with/without retinal detachment was 7.2 (2-10) years, and the mean follow-up period was 9.6 (5-16) years. Pathogenic variants COL2A1 (5 children) and COL11A1 (3 children) were confirmed in our cohort. In total, we operated on 13 eyes, 11 eyes with complicated RD and two eyes with multiple retinal defects, but without RD. At the end of the follow-up period, an attached retina was achieved 77% (10 eyes) with or without silicone oil tamponade: cryopexy alone was successful in one eye (10%), scleral buckling (EB) in five eyes (50%), and vitrectomy with silicone oil tamponade combined with EB in four eyes (40%). The mean number of surgeries was 2.3 per eye. The resulting best corrected visual acuity ranged from 0.03 to 0.1 in one eye, from 0.16 to 0.4 in two eyes, and from 0.5 to 1.0 in 7 eyes.

CONCLUSION

Repair of retinal tears with/without retinal detachment in patients with Stickler syndrome often requires multiple surgeries with combinations of cryopexy, scleral buckling, and/or vitrectomy with silicone oil tamponade. Treatment of the ocular complications arising from STL requires long-term comprehensive care.

Multimodal Retinal Imaging Findings in Two Cousins With VCAN-Related Vitreoretinopathy or Wagner Disease

Wagner disease is a rare, nonsyndromic vitreoretinopathy caused by autosomal dominant variants in the versican (VCAN) gene. It is associated with abnormalities of the vitreoretinal interface that can lead to peripheral traction and retinal detachments, which also occur in other vitreoretinopathies such as X-linked retinoschisis (XLRS), familial exudative vitreoretinopathy (FEVR) and Stickler syndrome. There is variability in the clinical phenotype in Wagner disease potentially due to variants in VCAN gene variants. In this article, we report a family harboring the VCAN c.9265+1G>C variant and describe the clinical and retinal findings in two members. [Ophthalmic Surg Lasers Imaging Retina 2022;53:639-643.].

Disrupted tenogenesis in masseter as a potential cause of micrognathia

Micrognathia is a severe craniofacial deformity affecting appearance and survival. Previous studies revealed that multiple factors involved in the osteogenesis of mandibular bone have contributed to micrognathia, but concerned little on factors other than osteogenesis. In the current study, we found that ectopic activation of Fgf8 by Osr2-cre in the presumptive mesenchyme for masseter tendon in mice led to micrognathia, masseter regression, and the disrupted patterning and differentiation of masseter tendon. Since Myf5-cre;Rosa26R-Fgf8 mice exhibited the normal masseter and mandibular bone, the possibility that the micrognathia and masseter regression resulted directly from the over-expressed Fgf8 was excluded. Further investigation disclosed that a series of chondrogenic markers were ectopically activated in the developing Osr2-cre;Rosa26R-Fgf8 masseter tendon, while the mechanical sensing in the masseter and mandibular bone was obviously reduced. Thus, it suggested that the micrognathia in Osr2-cre;Rosa26R-Fgf8 mice resulted secondarily from the reduced mechanical force transmitted to mandibular bone. Consistently, when tenogenic or myogenic components were deleted from the developing mandibles, both the micrognathia and masseter degeneration took place with the decreased mechanical sensing in mandibular bone, which verified that the loss of mechanical force transmitted by masseter tendon could result in micrognathia. Furthermore, it appeared that the micrognathia resulting from the disrupted tenogenesis was attributed to the impaired osteogenic specification, instead of the differentiation in the periosteal progenitors. Our findings disclose a novel mechanism for mandibular morphogenesis, and shed light on the prevention and treatment for micrognathia.

Zebrafish Model of Stickler Syndrome Suggests a Role for Col2a1a in the Neural Crest during Early Eye Development

Most cases of Stickler syndrome are due to autosomal-dominant COL2A1 gene mutations leading to abnormal type II collagen. Ocular findings include axial eye lengthening with vitreal degeneration and early-onset glaucoma, which can result in vision loss. Although COL2A1 is a major player in cartilage and bone formation, its specific role in eye development remains elusive. We investigated the role of Col2a1a in neural crest migration and differentiation during early zebrafish eye development. In situ hybridization, immunofluorescence, live imaging, exogenous treatments [10 μM diethylaminobenzaldehyde (DEAB), 100 nM all-trans retinoic acid (RA) and 1-3% ethanol (ETOH)] and morpholino oligonucleotide (MO) injections were used to analyze wildtype Casper (roy-/-;nacre-/-), TgBAC(col2a1a::EGFP), Tg(sox10::EGFP) and Tg(foxd3::EGFP) embryos. Col2a1a colocalized with Foxd3- and Sox10-positive cells in the anterior segment and neural crest-derived jaw. Col2a1a expression was regulated by RA and inhibited by 3% ETOH. Furthermore, MO knockdown of Col2a1a delayed jaw formation and disrupted the ocular anterior segment neural crest migration of Sox10-positive cells. Interestingly, human COL2A1 protein rescued the MO effects. Altogether, these results suggest that Col2a1a is a downstream target of RA in the cranial neural crest and is required for both craniofacial and eye development.

HODD: A Manually Curated Database of Human Ophthalmic Diseases with Symptom Characteristics and Genetic Variants Towards Facilitating Quick and Definite Diagnosis

Ophthalmic diseases are disorders that affect the eyes. Hundreds of causal genes and biological pathways have been reported to be closely correlated with ophthalmic diseases. However, these information are scattered across various resources, which has hindered a thorough and deep understanding of ophthalmic diseases. In the present work, we proposed the Human Ophthalmic Diseases Database (HODD), which currently deposits 730 ophthalmic diseases and 653 related genes and is available at http://bio-bigdata.cn/HODD/ . The disease-related information and genes related to ophthalmic diseases were collected from the several well-known databases. To comprehensively understand the ophthalmic diseases, the basic information was provided for each disease, including disease description, related genes, gene location, ocular and extraocular effect of the disease, protein-protein interaction and disease-associated pathways. All these data were reorganized and made accessible through multiple entrances. We hope that HODD will facilitate studies on ophthalmic diseases. The workflow for the construction of the HODD (Human Ophthalmic Diseases Database, http://bio-bigdata.cn/HODD/ ) database.

Into the Tissues: Extracellular Matrix and Its Artificial Substitutes: Cell Signalling Mechanisms

The existence of orderly structures, such as tissues and organs is made possible by cell adhesion, i.e., the process by which cells attach to neighbouring cells and a supporting substance in the form of the extracellular matrix. The extracellular matrix is a three-dimensional structure composed of collagens, elastin, and various proteoglycans and glycoproteins. It is a storehouse for multiple signalling factors. Cells are informed of their correct connection to the matrix via receptors. Tissue disruption often prevents the natural reconstitution of the matrix. The use of appropriate implants is then required. This review is a compilation of crucial information on the structural and functional features of the extracellular matrix and the complex mechanisms of cell–cell connectivity. The possibilities of regenerating damaged tissues using an artificial matrix substitute are described, detailing the host response to the implant. An important issue is the surface properties of such an implant and the possibilities of their modification.

Compendium of causative genes and their encoded proteins for common monogenic disorders

A compendium is presented of inherited monogenic disorders that have a prevalence of >1:20,000 in the human population, along with their causative genes and encoded proteins. "Simple" monogenic diseases are those for which the clinical features are caused by mutations impacting a single gene, usually in a manner that alters the sequence of the encoded protein. Of course, for a given "monogenic disorder", there is sometimes more than one potential disease gene, mutations in any one of which is sufficient to cause phenotypes of that disorder. Disease-causing mutations for monogenic disorders are usually passed on from generation to generation in a Mendelian fashion, and originate from spontaneous (de novo) germline founder mutations. In the past monogenic disorders have often been written off as targets for drug discovery because they sometimes are assumed to be rare disorders, for which the meager projected financial payoff of drug discovery and development has discouraged investment. However, not all monogenic diseases are rare. Here, we report that that currently available data identifies 72 disorders with a prevalence of at least 1 in 20,000 humans. For each, we tabulate the gene(s) for which mutations cause the spectrum of phenotypes associated with that disorder. We also identify the gene and protein that most commonly causes each disease. 34 of these disorders are caused exclusively by mutations in only a single gene and encoded protein.

Risk and Prevention of Retinal Detachments in Patients with Stickler Syndrome

BACKGROUND AND OBJECTIVE

To report the impact of prophylactic laser retinopexy in the prevention of retinal detachments (RDs) in patients with Stickler syndrome.

PATIENTS AND METHODS

This was a retrospective, comparative case series of patients with Stickler syndrome from the year 2000 to 2019. We compared the rate of RDs between individuals who did and did not receive prophylactic laser therapy. In patients with an RD, we compared the rate of RD in the fellow eye with and without prophylactic laser treatment.

RESULTS

A total of 95 eyes were identified. Fifty-four percent of the overall population was female. The RD rate was 26.7% among eyes without previous prophylactic laser retinopexy and 4.6% among eyes with previous prophylactic laser retinopexy. A Cox proportional model revealed that laser prophylaxis treatment had a statistically significant effect on the risk of RD or retinal tear during the 25-year survival period from birth (P = .034). Eyes receiving treatment were 70% less likely to experience RD or retinal tear (hazard ratio, 0.297; 95% CI, 0.097 to 0.913).

CONCLUSIONS

This study's results suggest a potential role for prophylactic laser retinopexy in the prevention of rhegmatogenous RD among patients with a clinical diagnosis of Stickler syndrome. [Ophthalmic Surg Lasers Imaging Retina. 2022;53:7-11.].

Controversy and Consideration of Refractive Surgery in Patients with Heritable Disorders of Connective Tissue

Heritable Disorders of Connective Tissue (HDCTs) are syndromes that disrupt connective tissue integrity. They include Osteogenesis Imperfecta (OI), Ehlers Danlos Syndrome (EDS), Marfan Syndrome (MFS), Loeys-Dietz Syndrome (LDS), Epidermolysis Bullosa (EB), Stickler Syndrome (STL), Wagner Syndrome, and Pseudoxanthoma Elasticum (PXE). Because many patients with HDCTs have ocular symptoms, commonly myopia, they will often present to the clinic seeking refractive surgery. Currently, corrective measures are limited, as the FDA contraindicates laser-assisted in-situ keratomileusis (LASIK) in EDS and discourages the procedure in OI and MFS due to a theoretically increased risk of post-LASIK ectasia, poor wound healing, poor refractive predictability, underlying keratoconus, and globe rupture. While these disorders present with a wide range of ocular manifestations that are associated with an increased risk of post-LASIK complications (e.g., thinned corneas, ocular fragility, keratoconus, glaucoma, ectopia lentis, retinal detachment, angioid streaks, and ocular surface disease), their occurrence and severity are highly variable among patients. Therefore, an HDCT diagnosis should not warrant an immediate disqualification for refractive surgery. Patients with minimal ocular manifestations can consider LASIK. In contrast, those with preoperative signs of corneal thinning and ocular fragility may find the combination of collagen cross-linking (CXL) with either photorefractive keratotomy (PRK), small incision lenticule extraction (SMILE) or a phakic intraocular lens (pIOL) implant to be more suitable options. However, evidence of refractive surgery performed on patients with HDCTs is limited, and surgeons must fully inform patients of the unknown risks and complications before proceeding. This paper serves as a guideline for future studies to evaluate refractive surgery outcomes in patients with HDCTs.

Benefits of Exome Sequencing in Children with Suspected Isolated Hearing Loss

Purpose: Hearing loss is characterized by an extensive genetic heterogeneity and remains a common disorder in children. Molecular diagnosis is of particular benefit in children, and permits the early identification of clinically-unrecognized hearing loss syndromes, which permits effective clinical management and follow-up, including genetic counselling. Methods: We performed whole-exome sequencing with the analysis of a panel of 189 genes associated with hearing loss in a prospective cohort of 61 children and 9 adults presenting mainly with isolated hearing loss. Results: The overall diagnostic rate using exome sequencing was 47.2% (52.5% in children; 22% in adults). In children with confirmed molecular results, 17/32 (53.2%) showed autosomal recessive inheritance patterns, 14/32 (43.75%) showed an autosomal dominant condition, and one case had X-linked hearing loss. In adults, the two patients showed an autosomal dominant inheritance pattern. Among the 32 children, 17 (53.1%) had nonsyndromic hearing loss and 15 (46.7%) had syndromic hearing loss. One adult was diagnosed with syndromic hearing loss and one with nonsyndromic hearing loss. The most common causative genes were STRC (5 cases), GJB2 (3 cases), COL11A1 (3 cases), and ACTG1 (3 cases). Conclusions: Exome sequencing has a high diagnostic yield in children with hearing loss and can reveal a syndromic hearing loss form before other organs/systems become involved, allowing the surveillance of unrecognized present and/or future complications associated with these syndromes.

Pleiotropy of a Stickler syndrome genotype

PURPOSE

To report a case of pleiotropy in the COL2A1 gene typically associated with Stickler Syndrome Type 1.

OBSERVATIONS

A patient with a confirmed mutation of the COL2A1 gene presented with an isolated retinitis pigmentosa phenotype.

CONCLUSIONS

The mutated COL2A1 gene in Stickler Syndrome Type 1 represents a site of pleiotropy, highlighting a change in phenotype across the same genotype potentially due to tissue alternative splicing.