Microtia: epidemiology and genetics

Whole-Genome Sequencing Identifies Two Novel Rare Mutations in BMP5 and BMP2 in Monozygotic Twins With Microtia

ABSTRACT

Microtia is a rare congenital anomaly of the ear; it is regulated by both genetic and environmental factors. However, the mechanisms underlying its pathogenesis are unknown. In this study, the genomes of 2-year-old twin sisters with right microtia were sequenced using human genome-wide sequencing, an approach useful for identifying mutations in genes responsible for congenital microtia. The phenotypes of the twin sisters included congenital microtia on the right side, abnormal auricle shape in the right external ear, a peanut shape for the residual ear, and complete atresia of the right external auditory canal. In the twin sisters, we identified a previously unknown mutation in BMP5(exon4:c.833- 4C>G), as well as a new mutation (exon2:c.G332T:p.S111I) in BMP2, both of which were confirmed using polymerase chain reaction-based amplification of the corresponding genome regions, followed by first-generation sequencing. The exon4:c.833-4C>G mutation in human BMP5 may be the main cause of microtia in the twin sisters. A pathogenic mutation in human BMP2 (exon2:c.G332T:p.S111I) may be responsible for the facial deformity in the twin sisters. Thus, our study demonstrates the potential of genome-wide sequencing for identifying novel mutations associated with microtia on the whole-genome scale and extends the mutation spectrum of BMP5. Additionally, our data suggest that BMP2 is another pathogenic gene associated with microtia.

Epidemiological Analysis and the Nomogram for Possible Risk Factors for Severe Microtia

BACKGROUND

Microtia is a severe congenital malformation of the external ear. This study aimed to explore the epidemiologic characteristics and the possible risk factors in patients with severe microtia in China, and integrate significant variables into a predictive nomogram.

METHODS

A total of 965 patients with microtia were included. This retrospective case study was conducted from July 2014 to July 2019 at Plastic Surgery Hospital in China. The detailed questionnaires concerning potential risk factors were completed and data were gathered. Chi-Square and Fisher tests were used to analyze the variables, and a multivariate logistic regression model was used to select variables related to severe microtia, and then construct a nomogram. The nomogram model was evaluated by the concordance index (C-index), calibration plot, and receiver operating characteristics (ROCs) curve. Bootstraps with 1000 resamples were applied to these analyses.

RESULTS

Of the 965 microtia patients, 629 (65.2%) were male and 867 (89.8%) were sporadic. The cases were observed more commonly in unilateral (83.1%) and right-sided (52.0%). And multiple malformations were observed in 392 (40.6%) cases. Multivariate logistic regression analysis showed that maternal age, miscarriage frequency, virus infection, anemia, using progesterone, paternal alcohol intake, and topography of living areas were associated with a higher risk of severe microtia. All the significant variables were combined into a predictive nomogram (C-index = 0.755,95% CI = 0.703-0.807). Higher prediction accuracy (adjusted C-index = 0.749) was further verified via bootstrap validation. The calibration plot showed good performance, and the ROCs curve analysis demonstrated high sensitivity and specificity.

CONCLUSIONS

Most microtia patients are male, sporadic, and accompanied by other malformations, which are similar to the phenotypic analysis results of other studies. A nomogram predicting severe microtia was constructed to provide scientific guidance for individualized prevention in clinical practice.

The Utility of Smartphone 3D Scanning, Open-Sourced Computer-aided Design, and Desktop 3D Printing in the Surgical Planning of Microtia Reconstruction: a Step by Step Guide and Concept Assessment

Introduction

Microtia, a congenital anomaly of the auricle with a wide spectrum of presentation with challenging reconstruction. Management depends on its severity with variable reconstructive options. Preoperative planning is crucial to achieve better results and decrease operative time. In this article, we aim to show the utility of an affordable technology with the use of a smartphone, an open-source computer-aided design (CAD) software, and a desktop 3D printer in planning future ear location for unilateral microtia reconstruction in step-by-step fashion.

Methodology

Facial 3D scanning was done using a smartphone that has a three-dimensional capture system. The scan was then used in an open-sourced CAD software. A mirror image mask was created by reflecting normal side anatomic features to the abnormal side. The mask constitutes the desired area for reconstruction given the ear anthropometrics. Finally, the model was 3D printed and fitted to the patient in which incision marking and framework location was planned.

Discussion

Ear reconstruction requires careful assessment and specific technicality in its anthropometric measures. One important aspect in surgical planning resides in future ear location that varies between person to person. This variability makes the reconstructive option more customized based on the patient's needs. The utility of CAD software in the measurement and planning can help predict and optimize postoperative results as possible; however, it has major technical demands and added surgical fees.

Conclusion

Herein, we demonstrate the efficacy of an easy-to-use system beneficial for preoperative planning that is affordable, time-saving, and cost effective.

Immune-Inflammatory Responses of an Acellular Cartilage Matrix Biomimetic Scaffold in a Xenotransplantation Goat Model for Cartilage Tissue Engineering

The rapid development of tissue engineering and regenerative medicine has introduced a new strategy for ear reconstruction, successfully regenerating human-ear-shaped cartilage and achieving the first clinical breakthrough using a polyglycolic acid/polylactic acid (PGA/PLA) scaffold. However, its clinical repair varies greatly among individuals, and the quality of regenerated cartilage is unstable, which seriously limits further clinical application. Acellular cartilage matrix (ACM), with a cartilage-specific microenvironment, good biocompatibility, and potential to promote cell proliferation, has been used to regenerate homogeneous ear-shaped cartilage in immunocompromised nude mice. However, there is no evidence on whether ACM will regenerate homogeneous cartilage tissue in large animals or has the potential for clinical transformation. In this study, xenogeneic ACM assisted with gelatin (GT) with or without autologous chondrocytes was implanted subcutaneously into goats to establish a xenotransplantation model and compared with a PGA/PLA scaffold to evaluate the immune-inflammatory response and quality of regenerated cartilage. The results confirmed the superiority of the ACM/GT, which has the potential capacity to promote cell proliferation and cartilage formation. Although there is a slight immune-inflammatory response in large animals, it does not affect the quality of the regenerated cartilage and forms homogeneous and mature cartilage. The current study provides detailed insights into the immune-inflammatory response of the xenogeneic ACM/GT and also provides scientific evidence for future clinical application of ACM/GT in cartilage tissue engineering.

Auricular reconstruction using Medpor combined with different hearing rehabilitation approaches for microtia

BACKGROUND

Congenital microtia-atresia affects patients in two specific ways: severe conductive hearing loss and difficulty in integrating into social environments due to auricle malformation.

AIMS/OBJECTIVES

To investigate the safety and efficacy of single-stage auricular reconstruction and hearing rehabilitation in children with microtia and external auditory canal atresia.

MATERIAL AND METHODS

From January 2016 to December 2019, we included 32 patients with microtia and external canal atresia who received auricle reconstruction with high-density polyethylene (Medpor) framework and three different hearing rehabilitation approaches at the Ninth People's Hospital affiliated to Shanghai Jiao Tong University School of Medicine. Twenty patients underwent the traditional external auditory canal and middle ear repair (EACR), eight patients were implanted with Bonebridge (BB) devices, and four patients were implanted with bone-anchored hearing aid (BAHA) in one stage. Postoperative changes in auricle morphology and hearing and speech recognition and occurrence of complications were evaluated.

RESULTS

After 6-24 months of follow-up, the auricle shape recovered well in all three groups, and the average score of 14 fine structures in the auricle was 9.43 (EACR), 10.67 (BB), and 9.75 (BAHA) points. The average score of auricle symmetry was 6.83 (EACR), 6.00 (BB), and 6.44 (BAHA) points. No significant differences in auricle shape were observed among the three groups (p > .05). After surgery, the average hearing improvement in the BB group was 43.33 dB, and the average speech recognition threshold declined to 42.28 dB. In the BAHA group, the average hearing improvement was 35 dB, and the average speech recognition threshold declined to 33.5 dB, similar to that of the BB group. However, in the EACR group, the average hearing improvement was only 4.13 dB, and the average speech recognition threshold declined to 11.36 dB. No vertigo, tinnitus, cerebrospinal fluid leakage, facial nerve paralysis, osseointegration failure, and other complications occurred in all the patients. In the EACR group, auricle stent fracture, ear canal restenosis, and canal atresia occurred in one patient each. In the BAHA group, two patients developed local ear infections.

CONCLUSIONS AND SIGNIFICANCE

The procedure of single-stage auricular reconstruction and hearing rehabilitation for microtia is feasible and effective. The appropriate method of hearing reconstruction should be determined by evaluating the development of the inner and middle ear of the patients. For those patients with poor development of the mastoid and ossicular chain, hearing aid devices are recommended to achieve a stable and significant hearing effect.

Does Prematurity Play a Role in Newborn Microtia-Anotia?

OBJECTIVE

Microtia-anotia (MA) describes a range of external ear anomalies which is commonly associated with various syndromes and malformations of the head and neck. Previous studies have suggested a strong association between MA and male sex, maternal diabetes, and Hispanic race/ethnicity. This study seeks to evaluate the associations between MA and preterm newborns in the United States.

METHODS

Population-based inpatient registry analysis was conducted. Kids' Inpatient Database (2016) was used to identify weighted in-hospital births with diagnosis of prematurity or MA. Demographic information was obtained, and odds ratios (ORs) were used to determine associations between prematurity and MA.

RESULTS

Among patients included in our dataset, 8.655% (326 285) were preterm and 0.016% (523) had MA. 0.003% (109) of patients were preterm and had MA. Preterm infants had 2.19 times the odds (95% C.I. = 1.78-2.69) of having MA when compared to the full-term population. The binary logistic regression model accounting for possible confounding variables produced an aOR of 1.48 (95% C.I. = 1.17-1.87) for the association between prematurity and MA.

CONCLUSION

Infants who are born preterm are more likely to have MA than full term infants. The current results will allow for improved risk stratification, maternal counseling, and interventions in the case of prematurity.

Changes in the Transcriptome and Proteome of Cartilage in Microtia

ABSTRACT

Congenital microtia is a severe physiological defect and is among the most common craniofacial defects. It is characterized by severe auricle dysplasia, external auditory canal atresia or stenosis, and middle ear malformation, though inner ear development is mostly normal with some hearing occurring through bone conduction. Auricular reconstruction is the only treatment for congenital microtia. In this study, the authors integrated messenger ribonucleic acid and mass spectrometry data of cartilage obtained from the affected and unaffected sides of 16 unilateral microtia patients who had undergone ear reconstruction surgery. The authors next performed functional analyses to investigate differences in the proteome of the affected and unaffected ears to elicit molecular pathways involved in microtia pathogenesis. The authors collected 16 pairs samples. Proteomic and transcriptomic analyses identified 47 genes that were differentially expressed in affected and unaffected cartilage. Integrated pathway analysis implicated the involvement of genes related to cell adhesion, extracellular matrix organization, and cell migration in disease progression. Through the integration of gene and protein expression data in human primary chondrocytes, the authors identified molecular markers of microtia progression that were replicated across independent datasets and that have translational potential.

Ear Abnormalities

Congenital ear abnormalities present an aesthetic and psychosocial concern for pediatric patients and their parents. Diagnosis of external ear deformities is based on clinical examination and is facilitated by an understanding of normal ear anatomy. Ear anomalies can be categorized as malformations or deformations. Malformations are characterized by absent anatomical structures of the ear (or absence of the ear itself), as exemplified by microtia and anotia. Ear deformations are characterized by ear anatomical landmarks that are present but are distorted or abnormal, with Stahl ear, constricted ear, and prominent ear being common presentations. Ear malformations will not improve with growth of the patient and uniformly require surgical intervention to recreate an anatomically typical ear. Although a small percentage of ear deformations can self-resolve, most patients with ear deformations will require nonsurgical or surgical reconstruction to achieve a normal or more aesthetic ear. In recent decades the use of nonsurgical ear splinting or molding has been recognized as a highly effective method in correcting a variety of congenital ear deformations when treatment is initiated in the first 8 weeks of life. The urgency in initiating nonsurgical treatment of ear deformations at an early age makes prompt recognition of these ear deformations essential because surgical correction remains the only viable reconstructive option in older infants and children.

Genetic and phenotypic analysis of 101 patients with developmental delay or intellectual disability using whole-exome sequencing

Whole-exome sequencing (WES) enables identification of pathogenic variants, including copy number variants (CNVs). In this study, we performed WES in 101 Japanese patients with unexplained developmental delay (DD) or intellectual disability (ID) (63 males and 38 females), 98 of them with trio-WES. Pathogenic variants were identified in 54 cases (53.5%), including four cases with pathogenic CNVs. In one case, a pathogenic variant was identified by reanalysis of exome data; and in two cases, two molecular diagnoses were identified. Among 58 pathogenic variants, 49 variants occurred de novo in 48 patients, including two somatic variants. The accompanying autism spectrum disorder and external ear anomalies were associated with detection of pathogenic variants with odds ratios of 11.88 (95% confidence interval [CI] 2.52-56.00) and 3.46 (95% CI 1.23-9.73), respectively. These findings revealed the importance of reanalysis of WES data and detection of CNVs and somatic variants in increasing the diagnostic yield for unexplained DD/ID. In addition, genetic testing is recommended when patients suffer from the autism spectrum disorder or external ear anomalies, which potentially suggests the involvement of genetic factors associated with gene expression regulation.

Farm Animals Are Long Away from Natural Behavior: Open Questions and Operative Consequences on Animal Welfare

Simple Summary

Animal welfare is a very important issue. One of the tasks of researchers is to provide explanations and possible solutions to questions arising from non-experts. This work analyzes part of the extensive literature on relationships between selection and domestic, mainly farm, animals’ behavior and deals with some very important themes, such as the role of regulations, domestication, and selection.

Abstract

The concept of welfare applied to farm animals has undergone a remarkable evolution. The growing awareness of citizens pushes farmers to guarantee the highest possible level of welfare to their animals. New perspectives could be opened for animal welfare reasoning around the concept of domestic, especially farm, animals as partial human artifacts. Therefore, it is important to understand how much a particular behavior of a farm animal is far from the natural one of its ancestors. This paper is a contribution to better understand the role of genetics of the farm animals on their behavior. This means that the naïve approach to animal welfare regarding returning animals to their natural state should be challenged and that welfare assessment should be considered.

Bioinformatics analysis of candidate genes involved in ethanol-induced microtia pathogenesis based on a human genome database: GeneCards

OBJECTIVE

Ethanol used by women during pregnancy increases the risk for microtia in the foetus. Traditionally, laboratory experiments and Mouse Genome Informatics (MGI) have been used to explore microtia pathogenesis. The aim of this study was to screen and verify hub genes involved in ethanol-induced microtia and to explore the potential molecular mechanisms.

METHODS

Overlapping genes related to ethanol and microtia were acquired from the GeneCards database and filtered by confidence score. These genes were further analysed via bioinformatics. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis results were visualized with the clusterProfiler R package. A protein-protein interaction (PPI) network was constructed based on data from the Search Tool for the Retrieval of Interacting Genes/Proteins (STRING) database.

RESULTS

Overall, 41 genes related to both ethanol and microtia were identified. The genes most relevant to ethanol-induced microtia pathogenesis included FGFR-2, FGFR-3, FGF-8, TP53, IGF1, SHH, CTNNB1, and PAX6, among others. Most genes were strongly enriched for tissue and organ development in GO analysis. Additionally, many genes were enriched in the Ras, FoxO, MAPK, and PI3K-Akt signalling pathways in KEGG analysis.

CONCLUSIONS

Bioinformatics analysis was conducted on genes currently known to be related to ethanol-induced microtia pathogenesis. We propose that mechanisms involving FGF-family genes, TP53, IGF1 and SHH contribute significantly to ethanol-induced microtia and the accompanying malformation of other structures.

Socioeconomic and clinical factors influencing treatment selection in microtia and aural atresia

OBJECTIVES

Patients with microtia and aural atresia have multiple options for treatment of conductive hearing loss (CHL) and auricle reconstruction; however, little is known about the factors influencing treatment selection. This study aims to review the socioeconomic and clinical data of microtia/atresia patients to evaluate congruency with national data and whether these factors affect treatment decisions.

METHODS

Retrospective review of patients evaluated in the microtia and atresia multidisciplinary clinic (MDC) at a tertiary academic children's hospital between 2008 and 2018. Outcomes included demographic, socioeconomic and clinical factors associated with hearing surgery and framework surgery.

RESULTS

373 patients were seen in the Microtia MDC: 193 (51.7%) were male, 187 (50.1%) identified as Hispanic and 23 (6.2%) identified as Asian. 267 (75.6%) patients received a nonsurgical bone conduction hearing device (BCHD); fitting at a younger age was associated with better nonsurgical BCHD compliance. Multivariate analysis was performed on the patients that were eligible for surgery based on age and appropriate follow-up. 70 (18.8%) patients had placement of an osseointegrated BCHD; inconsistent compliance with nonsurgical BCHD decreased the odds of proceeding with osseointegrated BCHD placement. 60 (16.1%) patients underwent framework surgery for external reconstruction. Placement of osseointegrated BCHD was the only factor that was associated with proceeding with framework surgery. Other assessed demographic and socioeconomic factors were statistically not associated with selection of surgical intervention.

CONCLUSION

Fitting a nonsurgical BCHD at a younger age is associated with higher likelihood of nonsurgical BCHD compliance, that is in turn associated with patients and families proceeding with osseointegrated BCHD and framework surgery.

Microtia: A Data Linkage Study of Epidemiology and Implications for Service Delivery

Introduction: Previous studies of microtia epidemiology globally have demonstrated significant geographical and ethnic variation, cited broadly as affecting 3-5 in 10,000 live births. The aim of this study was to determine the incidence of microtia in a largely homogeneous ethnic population in the United Kingdom (Wales) and to identify factors, such as distance and socioeconomic status, which may influence the access to surgical intervention. Materials and Methods: A retrospective cohort study was conducted using data linkage to identify patients born between 2000 and 2018 with a diagnosis of microtia. Microtia incidence was calculated using annual and geographic birth rates. Surgical operation codes were used to classify patients into those that had no surgery, autologous reconstruction or prosthetic reconstruction. Sociodemographic attributes were compared using descriptive statistics to determine differences in access to each type of surgical intervention. Results: A total of 101 patients were identified, 64.4% were male and the median age was 12 (8-16). The mean annual incidence was 2.13 microtia cases per 10,000 births over the 19-year study period. Both temporal and geographic variation was noted. The majority of patients undergoing surgery opted for autologous reconstruction (72.9%) at a median age of 9 (7-10) compared to 7 (5-8) for prosthetic reconstruction. Autologous reconstruction had a higher median number of surgeries (2, 1-3) than prosthetic (1.5, 1-2) and a higher median socioeconomic status of 3 (2-4) compared to 2 (1-4) for the prosthetic cohort. There were no statistically significant differences in the distance traveled for surgery. Discussion: This study highlights a role for data linkage in epidemiological analyses and provides a revised incidence of microtia in Wales. Although the majority of patients opted for autologous reconstruction, demographic disparities in socioeconomic status warrant further investigation, emphasizing the importance of striving for equity in accessibility to surgical intervention.

An Essential Requirement for Fgf10 in Pinna Extension Sheds Light on Auricle Defects in LADD Syndrome

The pinna (or auricle) is part of the external ear, acting to capture and funnel sound toward the middle ear. The pinna is defective in a number of craniofacial syndromes, including Lacrimo-auriculo-dento-digital (LADD) syndrome, which is caused by mutations in FGF10 or its receptor FGFR2b. Here we study pinna defects in the Fgf10 knockout mouse. We show that Fgf10 is expressed in both the muscles and forming cartilage of the developing external ear, with loss of signaling leading to a failure in the normal extension of the pinna over the ear canal. Conditional knockout of Fgf10 in the neural crest fails to recapitulate this phenotype, suggesting that the defect is due to loss of Fgf10 from the muscles, or that this source of Fgf10 can compensate for loss in the forming cartilage. The defect in the Fgf10 null mouse is driven by a reduction in proliferation, rather than an increase in cell death, which can be partially phenocopied by inhibiting cell proliferation in explant culture. Overall, we highlight the mechanisms that could lead to the phenotype observed in LADD syndrome patients and potentially explain the formation of similar low-set and cup shaped ears observed in other syndromes.

Identification of a novel CYP26A1 mutation in a Chinese family with congenital microtia

OBJECTIVES

Microtia is defined as a congenital malformation characterized by a small, abnormally shaped auricle, with atresia or stenosis of the auditory canal. This study investigated a mutation of the cytochrome P450, family 26, subfamily A, polypeptide 1(CYP26A1) gene, which is considered important in craniofacial development, in a family affected with microtia.

METHODS

Whole-exome sequencing (WES) was performed on the proband and his family members to identify disease-associated variants. Computational predictions of the altered protein were analyzed using several bioinformatics tools. The wild-type (WT) and mutant forms of CYP26A1 cDNA were transfected into human embryonic kidney cells, and the mRNA and protein levels were compared using quantitative polymerase chain reaction (qPCR) and Western blot analyses.

RESULTS

In this two-generation family, the proband and his mother were diagnosed with unilateral microtia. Unilateral microtia and ipsilateral accessory ear were observed in one of the twins, who were sisters of the proband. The father and the other twin showed no abnormal clinical features. A heterozygous mutation of a C to T in the CYP26A1 gene, which leads to truncation of the CYP26A1 protein, was identified in this family. The nonsense mutation cosegregated with patients and was absent in normal members of the family. The prediction software indicated that it was a possibly pathogenic mutation. The structure of the protein varied significantly between the WT and mutant proteins. Functional analysis showed that this mutation caused a significant decrease in both the mRNA and protein levels.

CONCLUSIONS

Our findings suggest that this mutation of CYP26A1 may be a pathogenic factor leading to the phenotypes of microtia and accessory ear in this family. Further studies are needed to prove the function of this mutation and to explore the possible mechanism by which this variant is involved in the occurrence of microtia.

Concepts Important to Patients With Facial Differences: A Qualitative Study Informing a New Module of the FACE-Q for Children and Young Adults

Objective:

The concepts important to children and young adults who undergo treatments for facial differences are not well-defined. Measurement of treatment outcomes from the patient’s perspective is necessary to ensure goals of treatment are met. We aimed to identify concepts important to children and young adults with facial differences through a qualitative study.

Design:

An interpretive description qualitative approach was followed. Semistructured interviews were conducted, transcribed verbatim, and coded using a line-by-line approach. Qualitative analysis led to the development of a conceptual framework of outcomes important to patients.

Setting:

Interviews were conducted in Canada and the United Kingdom at home, by telephone, or in the hospital.

Participants:

Participants (N = 72) were recruited between May and June 2014 from craniofacial clinics at the Hospital for Sick Children (Toronto) and Great Ormond Street Hospital (London). Participants included anyone with a visible and/or functional facial difference aged 8 to 29 years and fluent in English, excluding patients with a cleft. The sample included 38 females and 34 males, with a mean age of 13.9 years, and included 28 facial conditions (11 facial paralysis, 18 ear anomalies, 26 skeletal conditions, and 17 soft tissue conditions).

Results:

Analysis led to identification of important concepts within 4 overarching domains: facial appearance, facial function, adverse effects of treatment, and health-related quality of life (psychological, social, and school function).

Conclusions:

Our study provides an understanding of concepts important to children and young adults with facial differences.

Imaging of the Fetal Zygomatic Bone: A Key Role in Prenatal Diagnosis of First Branchial Arch Syndrome

OBJECTIVES

First arch syndromes are congenital defects caused by failure of neural crest cells to migrate into the first branchial arch. First arch syndrome is classified into 2 main clinical manifestations: Treacher Collins syndrome, characterized by bilateral underdevelopment of the zygomatic bones; and Pierre Robin sequence. The aim of this study was to describe the feasibility of visualization of the fetal zygomatic bone and assess its application in cases referred for features suggestive of first arch syndrome.

METHODS

A prospective cohort study was conducted. The feasibility of visualization of the zygomatic bone was performed in 50 sequential fetuses with a normal anatomic scan between 12 and 24 weeks' gestation using 3-dimensional sonography. Following this, cases referred for targeted scans for suspected first branchial arch syndrome were assessed for the presence or absence of the zygomatic bones.

RESULTS

Visualization of the fetal zygomatic bone was feasible in all low-risk cases. Cases referred for targeted scans included 11 isolated cases of micrognathia or retrognathia, 3 cases of microtia, and 3 cases of auricular or facial vestiges. Within this group, the zygomatic bones were visualized in all but 2 cases. No associated extrafacial malformations were detected; therefore, this phenotype was consistent with Treacher Collins syndrome.

CONCLUSIONS

Prenatal imaging of the zygomatic bones offers a clinically based sonographic approach to cases referred for features suggestive of first arch syndrome and enables differentiation between the 2 main clinical manifestations: Treacher Collins syndrome and Pierre Robin sequence.

Whole-Exome Sequencing of Discordant Monozygotic Twin Families for Identification of Candidate Genes for Microtia-Atresia

Objective

We used data from twins and their families to probe the genetic factors contributing to microtia-atresia, in particular, early post-twinning variations that potentially account for the discordant phenotypes of monozygotic twin pairs.

Methods

Six families of monozygotic twins discordant for congenital microtia-atresia were recruited for study. The six patients shared a consistent clinical phenotype of unilateral microtia-atresia. Whole-exome sequencing (WES) was performed for all six twin pairs and their parents. Family segregation and multiple bioinformatics methods were applied to identify suspicious mutations in all families. Recurring mutations commonly detected in at least two families were highlighted. All variants were validated via Sanger sequencing. Gene Ontology (GO) analysis was performed to identify candidate gene sets and related pathways. Copy number variation (CNV), linkage analysis, association analysis and machine learning methods were additionally applied to isolate candidate mutations, and comparative genomics and structural modeling tools used to evaluate their potential roles in onset of microtia-atresia.

Results

Our analyses revealed 61 genes with suspected mutations associated with microtia-atresia. Five (HOXA4, MUC6, CHST15, TBX10, and AMER1) contained 7 de novo mutations that appeared in at least two families, which have been previously reported as pathogenic for other diseases. Among these, HOXA4 (c.920A>C, p.H307P) was determined as the most likely pathogenic variant for microtia-atresia. GO analysis revealed four gene sets involving 11 pathways potentially related to underlying pathogenesis of the disease. CNVs in three genes (UGT2B17, OVOS, and KATNAL2) were detected in at least two families. Linkage analysis disclosed 13 extra markers for the disease, of which two (FGFR1 and EYA1) were validated via machine learning analysis as plausible candidate genes for the disease.

Conclusion

Based on comprehensive genetic and bioinformatic analyses of WES data from six families of discordant monozygotic twins with microtia-atresia, we identified multiple candidate genes that may function in post-twinning onset of the disease. The collective findings provide novel insights into the pathogenesis of congenital microtia-atresia.

Protein profile of ear auricle cartilage and the important role of ITGB1/PTK2 in microtia

BACKGROUND

Microtia is a congenital malformation of the external ear that involves anything from a small reduction in size to a complete absence. The external ear is composed of elastic cartilage which is also the important skeleton of the outer ear. However no previous study explored the difference between abnormal elastic cartilage and normal cartilage in the molecular level.

METHODS

Microtia cartilage and normal cartilage tissue samples from patients subjected to autologous costal cartilage reconstruction were obtained in surgery. Total proteins were extracted and purified, and then proteomic analyzed via LC-MS/MS using DDA/DIA data collection methods. Proteins were also isolated with lysis beads and then analyzed via antibody chip. Differentially expressed proteins were identified in both experiments and further analyzed with functional enrichment analysis and KEGG pathway analysis. Valuable regulatory gene expression level was verified by RT-PCR.

RESULTS

A total of 4178 protein types were identified in the DDA experiment. A total of 2154 proteins were quantified, 172 of which were significantly upregulated and 82 downregulated in the microtia group (P < 0.05). Antibody chip detection allowed identification of 584 protein phosphorylation sites with 102 upregulation sites and 9 downregulation sites (P < 0.05). Differentially altered proteins were annotated to 143 KEGG pathways, while differentiated phosphate site-associated genes were annotated into 21 KEGG pathways. Two intersecting pathways, the PI3K/AKT/mTOR pathway and the focal adhesion pathway, may paly important role on ear auricle cartilage development. One item is significant in both differential protein expression and phosphorylation. Integrin beta-1, that is downregulated in protein quantification of the microtia group. The mean ITGB1 mRNA level of the microtia patient group was significantly lower than in the healthy control group (P = 0.0007 < 0.05). And the gene expression of downstream gene PTK2 was also decreased. (P = 0.0288 < 0.05).

CONCLUSION

The research locates the key protein Integrin Beta-1, and verified it at the mRNA level. The increasing level of ITGB1 and decreasing of PTK2 may play an important role in congenital ear deformity. This research will inspire more otolaryngologists and orthopedics doctors to pay attention to the etiology and mechanism of microtia.

Cross-Sectional Imaging Evaluation of Congenital Temporal Bone Anomalies: What Each Radiologist Should Know

Hearing loss in pediatric age group is associated with many congenital temporal bone disorders. Aberrant development of various ear structures leads into either conductive or sensorineural hearing loss. Knowledge of the embryology and anatomical details of various compartments of the ear help better understanding of such disorders. In general, abnormalities of external and middle ears result in conductive hearing loss. Whereas abnormalities of inner ear structures lead into sensorineural hearing loss. These abnormalities could occur as isolated or part of syndromes. Temporal bone disorders are a significant cause of morbidity and developmental delays in children. Imaging evaluation of children presented with hearing loss is paramount in early diagnosis and proper management planning. Our aim is to briefly discuss embryology and anatomy of the pediatric petrous temporal bones. The characteristic imaging features of commonly encountered congenital temporal bone disorders and their associated syndromes will be discussed.

Outcomes for School-Aged Children with Aural Atresia

This study compared the language, reading, classroom, and quality of life outcomes of primary school-aged children with aural atresia (AA) to matched controls. Participants included 10 children with AA (eight unilateral) and 10 children with typical hearing matched by chronological and mental age. All children with AA had been fitted with an amplification device. Outcome measures included standardized tests of language, reading, and functional communication questionnaires of children's classroom performance and hearing quality of life. The children with AA recorded significantly reduced hearing quality of life. The two groups did not differ on any other measures. The present preliminary findings suggest that children with AA who receive early amplification have similar language, communication, reading, and classroom outcomes as their typically hearing peers. Despite these promising outcomes, however, the children's quality of life is significantly reduced. Further research is needed to further elucidate these findings.

The effect of anatomical variables and use of the Lifts system on hearing outcomes after implantation of an active transcutaneous bone conduction device in bilateral congenital conductive hearing loss

Background

Malformations of the temporal bone present different challenges to the implantation of a transcutaneous active bone conduction device, such as Bonebridge (Med-el, Innsbruck, Austria). This study aims to describe the benefits of high-resolution computed tomography (HRCT) in preoperative assessment and to analyze whether characteristics of the mastoid process, intraoperative compression of the dura or sigmoid sinus, and the use of the Lifts system, lead to differences in audiological performance after implantation.

Methods

We examined 110 cases of congenital microtia. The structure of the temporal bone was examined using HRCT and a 3D simulation software program. The mean anteroposterior mastoid bone thickness from the external auditory canal to the sigmoid sinus was measured (a measurement referred to as “AP”, hereafter). Sound field threshold (SFT), speech reception threshold (SRT) in noise, and word recognition score (WRS) in quiet, before and after implantation, were also measured. Independent variables were recorded in all patients: mastoid type (well pneumatized or poorly pneumatized), the presence of dural or sigmoid sinus compression, and the use of the Lifts system.

Results

We found that the mean AP in the non-compression group was 16.2 ± 2.3 mm and in the compression group, 13.1 ± 2.9 mm (p < 0.001). We analyzed the hearing improvement of patients grouped by mastoid development, dural or sigmoid sinus compression, and use of the Lifts system, and found that these factors did not interact and that they had no influence on the hearing outcomes (p > 0.05).

Conclusions

The AP dimension in the non-compression group was significantly larger than that in the compression group. This finding combined with the ROC curve analysis revealed the AP dimension was a high-accuracy predictor of potential surgical complications involving the dura and sigmoid sinus compression. Further analysis revealed that there was no interaction between the chosen variables: mastoid type, dural or sigmoid sinus compression, and the use of the Lifts system, and that all of these factors had no significant impact on hearing performance. Bonebridge was shown to produce effective and stable bone conduction and to improve patients’ hearing performance.

Modeling Normal and Pathological Ear Cartilage in vitro Using Somatic Stem Cells in Three-Dimensional Culture

Microtia (underdeveloped ear) is a rare congenital dysmorphology affecting the development of the outer ear. Although human microtic cartilage has not been fully characterized, chondrogenic cells derived from this tissue have been proposed as a suitable source for autologous auricular reconstruction. The aim of this study was to further characterize native microtic cartilage and investigate the properties of cartilage stem/progenitor cells (CSPCs) derived from it. Two-dimensional (2D) systems are most commonly used to assess the chondrogenic potential of somatic stem cells in vitro, but limit cell interactions and differentiation. Hence here we investigated the behavior of microtic CSPCs in three-dimensional spheroid cultures. Remarkable similarities between human microtic cartilages from five patients, as compared to normal cartilage, were observed notwithstanding possibly different etiologies of the disease. Native microtic cartilage displayed poorly defined perichondrium and hyper-cellularity, an immature phenotype that resembled that of the normal developing human auricular cartilage we studied in parallel. Crucially, our analysis of microtic ears revealed for the first time that, unlike normal cartilage, microtic cartilages are vascularized. Importantly, CSPCs isolated from human microtic and normal ear cartilages were found to recapitulate many characteristics of pathological and healthy tissues, respectively, when allowed to differentiate as spheroids, but not in monolayer cultures. Noteworthily, starting from initially homogeneous cell pellets, CSPC spheroids spontaneously underwent a maturation process in culture, and formed two regions (inner and outer region) separated by a boundary, with distinct cell types that differed in chondrogenic commitment as indicated by expression of chondrogenic markers. Compared to normal ear-derived spheroids, microtic spheroids were asymmetric, hyper-cellularized and the inner and outer regions did not develop properly. Hence, their organization resembled that of native microtic cartilage. Together, our results identify novel features of microtic ears and highlight the importance of 3D self-organizing in vitro systems for better understanding somatic stem cell behavior and disease modeling. Our observations of ear-derived chondrogenic stem cell behavior have implications for choice of cells for tissue engineered reconstructive purposes and for modeling the etiopathogenesis of microtia.

High-resolution computed tomography evaluation of congenital aural atresia - how useful is this?

OBJECTIVE

To depict various temporal bone abnormalities on high-resolution computed tomography in congenital aural atresia patients, and correlate these findings with auditory function test results and microtia subgroup.

METHODS

Forty patients (56 ears) with congenital malformation of the auricle and/or external auditory canal were evaluated. Auricles were graded according to Marx's classification, divided into subgroups of minor (grades I and II) and major (III and IV) microtia. Other associated anomalies of the external auditory canal, tympanic cavity, ossicular status, oval and round windows, facial nerve, and inner ear were evaluated.

RESULTS

Minor and major microtia were observed in 53.6 and 46.4 per cent of ears respectively. Mean hearing levels were 62.47 and 62.37 dB respectively (p = 0.98). The malleus was the most commonly dysplastic ossicle (73.3 vs 80.8 per cent of ears respectively, p = 0.53). Facial nerve (mastoid segment) abnormalities were associated (p = 0.04) with microtia subgroup (80 vs 100 per cent in minor vs major subgroups).

CONCLUSION

Microtia grade was not significantly associated with mean hearing levels or other ear malformations, except for external auditory canal and facial nerve (mastoid segment) anomalies. High-resolution computed tomography is essential in congenital aural atresia, before management strategy is decided.

Exploring the Experiences of Adults With Microtia: A Qualitative Study

OBJECTIVE

Microtia is a medically complex condition, with the option of surgery to address hearing and reconstruct the ear. The current study explored adults' experiences of microtia, with a particular focus on the psychosocial impact and experiences of ear reconstruction. The ultimate aim was to identify areas for support and future research that could improve patient care.

DESIGN

Fifteen adults (12 females) aged between 20 and 62 years took part in semi-structured interviews. Interviews were audio-recorded, transcribed verbatim, and analyzed using inductive thematic analysis.

RESULTS

Three main themes were identified in the data: microtia as an invisible difference, surgery as a welcome opportunity, and living well with microtia. Participants had incorporated microtia into their self-concept and did not report a lasting negative impact on their lives. However, some psychosocial challenges were reported, including anxiety about showing their ears (even after reconstruction), disclosing their diagnosis to romantic partners, surgical decision-making, and feeling unsupported in the work environment.

CONCLUSION

Individuals with microtia may benefit from psychosocial interventions to increase confidence, access to support for treatment decision-making, and guidance around disclosing microtia to employers.

An analytical study of neocartilage from microtia and otoplasty surgical remnants: A possible application for BMP7 in microtia development and regeneration

To investigate auricular reconstruction by tissue engineering means, this study compared cartilage regenerated from human chondrocytes obtained from either microtia or normal (conchal) tissues discarded from otoplasties. Isolated cells were expanded in vitro, seeded onto nanopolyglycolic acid (nanoPGA) sheets with or without addition of bone morphogenetic protein-7 (BMP7), and implanted in nude mice for 10 weeks. On specimen harvest, cartilage development was assessed by gross morphology, histology, and RT-qPCR and microarray analyses. Neocartilages from normal and microtia surgical tissues were found equivalent in their dimensions, qualitative degree of proteoglycan and elastic fiber staining, and quantitative gene expression levels of types II and III collagen, elastin, and SOX5. Microarray analysis, applied for the first time for normal and microtia neocartilage comparison, yielded no genes that were statistically significantly different in expression between these two sample groups. These results support use of microtia tissue as a cell source for normal auricular reconstruction. Comparison of normal and microtia cells, each seeded on nanoPGA and supplemented with BMP7 in a slow-release hydrogel, showed statistically significant differences in certain genes identified by microarray analysis. Such differences were also noted in several analyses comparing counterpart seeded cells without BMP7. Summary data suggest a possible application for BMP7 in microtia cartilage regeneration and encourage further studies to elucidate whether such genotypic differences translate to phenotypic characteristics of the human microtic ear. The present work advances understanding relevant to the potential clinical use of microtia surgical remnants as a suitable cell source for tissue engineering of the pinna.

Duplications involving the long range HMX1 enhancer are associated with human isolated bilateral concha-type microtia

Background

Microtia is a congenital anomaly of ear that ranges in severity from mild structural abnormalities to complete absence of the outer ears. Concha-type microtia is considered to be a mild form. The H6 family homeobox 1 transcription factor gene (HMX1) plays an important role in craniofacial structures development. Copy number variations (CNVs) of a downstream evolutionarily conserved enhancer region (ECR) of Hmx1 associated with ear and eye abnormalities have been reported in different animals, but not yet in human. To date, no genetic defects responsible for isolated human microtia has been reported except for mutations in HOXA2. Here we recruited five Chinese families with isolated bilateral concha-type microtia, and attempt to identify the underlying genetic causes.

Methods

Single Nucleotide polymorphism (SNP) array was performed to map the disease locus and detect CNVs on a genome scale primarily in the largest family (F1). Whole genome sequencing was performed to screen all SNVs and CNVs in the candidate disease locus. Array comparative genomic hybridization (aCGH) was then performed to detect CNVs in the other four families, F2-F5. Quantitative real-time polymerase chain reaction (qPCR) was used to validate and determine the extent of identified CNVs containing HMX1-ECR region. Precise breakpoints in F1 and F2 were identified by gap-PCR and sanger sequencing. Dual-luciferase assays were used to detect the enhancer function. qPCR assays were also used to detect HMX1-ECR CNVs in 61 patients with other types mictrotia.

Results

Linkage and haplotype analysis in F1 mapped the disease locus to a 1.9 Mb interval on 4p16.1 containing HMX1 and its downstream ECR region. Whole genome sequencing detected no potential pathogenic SNVs in coding regions of HMX1 or other genes within the candidate disease locus, but it detected a 94.6 Kb duplication in an intergenic region between HMX1 and CPZ. aCGH and qPCRs also revealed co-segregated duplications in intergenic region downstream of HMX1 in the other four families. The 21.8 Kb minimal overlapping region encompassing the core sequences consensus with mouse ECR of Hmx1. Luciferase assays confirmed the enhancer function in human sequences, and proved that HOXA2 could increase its enhancer activity. No CNVs were detected in HMX1-ECR regions in 61 patients with other type of microtia.

Conclusion

Duplications involving long range HMX1 enhancers are associated with human isolated bilateral concha-type microtia. We add to evidences in human that copy number variations in HMX1-ECR associates with ear malformations, as in other species. This study also provides an additional example of functional conserved non-coding elements (CNEs) in humans.

Long-term Outcomes of Clip Coupler Implantation in Patients with Unilateral Congenital Aural Atresia

OBJECTIVE

To evaluate the long-term safety and efficacy of the Clip coupler attached to the stapes head in patients with unilateral congenital aural atresia (CAA).

METHODS

This single-center retrospective study included 16 Mandarin-speaking patients who had unilateral microtia accompanied by CAA. All patients were divided into two groups: the short-term follow-up group (n = 9) and the long-term follow-up group (n = 7). The floating mass transducer of the Vibrant Soundbridge (VSB) was positioned in the stapes head by the Clip coupler. The safety of the VSB was investigated by comparing preoperative and postoperative bone-conduction (BC) thresholds as well as by complications. The effectiveness was evaluated by functional gain (FG), word recognition score (WRS), speech reception threshold (SRT) and signal-to-noise ratio (SNR).

RESULTS

Pre- and post-operative BC thresholds were no different in all patients. And no complications developed. VSB-aided thresholds in the free-field had improved significantly in both short- and long-term follow-up groups. The improvements of WRS were observed in two groups. The monosyllabic VSB-aided WRS in the long-term follow-up group was significantly higher than that in the short-term follow-up group. When speech was from the impaired ear and noise presented to the side of normal ear (S_VSBN_CL), lower SNRs were found in two groups after VSB implantation. However, there was no statistical difference in aided SNR between the two groups at S_VSBN_CL status.

CONCLUSIONS

Our results show that the FMT connected to the stapes head is a secure and useful device for patients with unilateral CHL/MHL, not only in terms of improved hearing thresholds, but also improved speech intelligibility in quiet and noisy environments.

Renal anomalies and microtia: Determining the clinical utility of screening affected children

OBJECTIVES

Microtia is a congenital ear anomaly that hinders quality of life. Microtia patients, both syndromic and in isolation, may be at-risk for significant renal anomalies that can go undetected at the time of birth. The goal of this study was to characterize the prevalence of renal anomalies among microtia patients at our institution in order to guide optimal patient management. Current guidelines suggest performing a renal ultrasound when there is presence of preauricular pits and ear anomalies in association with dysmorphic features, but not in cases of isolated microtia and atresia.

DESIGN

A retrospective review of 237 children with microtia was conducted from 2001 through 2018 at our tertiary-care pediatric institution, of which 98 also had a documented renal ultrasound. Patients were identified as syndromic or non-syndromic. Data endpoints included renal ultrasounds performed, structural anomalies found, and follow-up.

RESULTS

Among the 237 patients, 98 had received renal ultrasounds. 12% of the total cohort was found to be syndromic, the most common being Goldenhar. Structural anomalies were detected in 24% of the 98 patients that underwent ultrasound and included disorders such as pelviectasis, renal ectopia, duplicated collecting systems, and renal agenesis. A third of patients with anomalies required follow-up with nephrology for chronic kidney disease or renal failure. Of note, 21% of non-syndromic patients and 43% of syndromic patients screened had an abnormality on ultrasonography.

CONCLUSIONS

Children with microtia are at a significant risk of structural renal abnormalities, even when isolated outside of a genetic syndrome. We recommend the strong consideration of performing a screening renal ultrasound in all patients with microtia. Prospective data would be helpful in developing future clinical guidelines regarding the utility of screening ultrasonography.

Duplication in ECR Near HMX1 and a SNP in GATA6 Genes Regulate Microtia in Awassi Sheep

Microtia and anotia are hereditary traits characterized by an underdevelopment or complete absence of the outer ear. These congenital malformations observed in many species can exist as part of various syndromes or as an isolated trait as seen in the fat-tailed Awassi sheep breed. Our study aims to identify the genetic mutations causing microtia in Awassi sheep by DNA sequencing. DNA was extracted from blood samples randomly collected from 84 Awassi sheep (16 earless, 41 short ear and 27 normal ear) across different farms. GATA6 exons 1, 2, 4, 6 and 7, CLRN1 intron 3, DCC intron 2, ECR near HMX1 and the intergenic region between GATA6 and MIB1 genes were screened, amplified and sequenced. Allele and genotype frequencies were calculated by direct counting. Association was performed using chi-squared test for goodness-of-fit. Results showed mutations in only two genes significantly associated with microtia in Awassi: duplication in part of ECR near HMX1 (6:114293121-6:114293196) and a SNP at GATA6 exon 7 (23:34498242). Association results revealed that the ECR locus accounts for the microtia phenotype, while GATA6 exon 7 acts as a modifier gene. Genetic screening for these loci can be used to improve selection against microtia in Awassi sheep.

Sound-localisation performance in patients with congenital unilateral microtia and atresia fitted with an active middle ear implant

OBJECTIVE

This study assessed the safety and sound-localisation ability of the Vibrant Soundbridge (VSB) (Med-EL, Innsbruck, Austria) in patients with unilateral microtia and atresia (MA).

METHODS

This was a single-centre retrospective research study. Twelve subjects with unilateral conductive hearing loss (UCHL) caused by ipsilateral MA were recruited, each of whom underwent VSB implantation and auricular reconstruction. The bone-conduction (BC) threshold was measured postoperatively, and the accuracy of sound localisation was evaluated at least 6 months after surgery. Horizontal sound-localisation performance was investigated with the VSB activated and inactivated, at varying sound stimuli levels (65, 70 and 75 dB SPL). Localisation benefit was analysed via the mean absolute error (MAE).

RESULTS

There was no statistical difference in mean BC threshold of impaired ears measured preoperatively and postoperatively. When compared with VSB-inactivated condition, the MAE increased significantly in unilateral MA patients in the VSB-activated condition. Besides, sound-localisation performance worsened remarkably when sound was presented at 70 dB SPL and 75 dB SPL. Regarding the side of signal location, the average MAE with the VSB device was much higher than that without the VSB when sound was from the normal-hearing ear. However, no significant difference was observed when sound was located from the impaired ear.

CONCLUSION

This study demonstrates that in patients with unilateral MA, the VSB device does not affect inner-ear function. Sound-localisation ability is not improved, but deteriorated at follow-up. Our results suggest that the VSB-aided localisation abilities may be related to the thresholds between the ears, plasticity of auditory system and duration of use of VSB.

Biocompatible implant mimicking cartilage: A new horizon for reconstructive facial field

Cartilage is avascular with limited to no regenerative capacity, so its loss could be a challenge for reconstructive surgery. Current treatment options for damaged cartilage are also limited. In this aspect there is a tremendous need to develop an ideal cartilage-mimicking biomaterial that could repair maxillofacial defects. Considering this fact in this study we have prepared twelve silicone-based materials (using Silicone 40, 60, and 80) reinforced with hydroxyapatite, tri-calcium phosphate, and titanium dioxide which itself has proven their efficacy in several studies and able to complement the shortcomings of using silicones. Among the mechanical properties (Young's modulus, tensile strength, percent elongation, and hardness), hardness of Silicone-40 showed similarities with goat ear (P > .05). Silicone peaks have been detected in FTIR. Both AFM morphology and SEM images of the samples confirmed more roughed surfaces. All the materials were nonhemolytic in hemocompatibility tests, but among the twelve materials S2, S3, S5, and S6 showed the least hemolysis. For all tested bacterial strains, adherence was lower on each material than that grown on the plain industrial silicone material which was used as a positive control. S2, S3, S5, and S6 samples were selected as the best based on mechanical characterizations, surface characterizations, in vitro hemocompatibility tests and bacterial adherence activity. So, outcomes of this present study would be promising when developing ideal cartilage-mimicking biocomposites and their emerging applications to treat maxillofacial defects due to cartilage damage.

Ear malformations: what do radiologists need to know?

Ear malformations represent 50% of ear, nose and throat malformations. Ear malformations cause conductive hearing loss (CHL) and/or sensorineural hearing loss (SNHL) with a significant childhood disability worldwide. Early accurate diagnosis and treatment are mandatory to enhance language and speech development. Understanding the embryology of the ear explains the outcome of ototoxic prenatal insult according to the affected gestational age and the incidence of association among inner, middle, and external ear malformations. Computed tomography (CT) and magnetic resonance imaging (MRI) examinations of the temporal bone are used in the evaluation of ear malformations. In this review article, the spectrum of ear malformations is discussed in detail with hints on the ear embryology, the ear radiological anatomy, and radiological determinant factors of operative reconstruction of ear anomalies.

Characteristics of 43 multiple auricular deformity case families and auricle morphology in 463 microtia patients in South China

Background

Earlier studies have suggested that microtia is a genetic disease with a worldwide incidence of microtia is between 0.83/10,000 and 17.40/10,000. For microtia, auricle morphology is the most crucial characteristic. However, no studies have been performed to characterize the genetic similarity of microtia and auricle morphology similarity. For the sporadic patients, the relationship between the gestational age of parents and the incidence of microtia is unclear. To obtain the characteristics of auricular deformity multiple case family (AD-MCF) and clarify the relationship between genetic similarity and auricle morphology similarity in AD-MCF.

Methods

This study included 463 AD patients who were diagnosed by Sun Yat-sen Memorial Hospital, Sun Yat-sen University, from 2013 to 2019. Among these patients, 116 are from 43 MCF and the other 347 patients are sporadic. For the patients from families, the disease status of the four generations of immediate family members and the family tree map were collected to analyze the similarity of auricle shape in family members. A score evaluated the similarity of auricle shape according to the structure of the residual ear and the similarity in the morphology of each auricle. Moreover, the population distribution of AD and the gestational age of patients were further analyzed.

Results

From 2013 to 2019, a total of 463 patients were diagnosed as microtia in our hospital. There were 427 patients with unilateral disease and 36 patients with bilateral disease. Among them, 116 patients were from 34 families and 9 de novo families. The total scores of patients in different genetic difference levels were compared and were found significantly different (P<0.001). Moreover, 58.14% of families were consistent with the law of chromosomal recessive genetic diseases. Importantly, we found that the gestational age of father in microtia de novo families is 30.94±0.75, and mother in de novo is 28.39±0.73 that is significantly higher than the gestational ages of parents from microtia families with P value =0.0001.

Conclusions

The auricle similarity between family members is positively related to the genetic distance between family members. The microtia patients are potentially associated with the gestational ages of parents.

3D printing for tissue engineering in otolaryngology

Airway and other head and neck disorders affect hundreds of thousands of patients each year and most require surgical intervention. Among these, congenital deformity that affects newborns is particularly serious and can be life-threatening. In these cases, reconstructive surgery is resolutive but bears significant limitations, including the donor site morbidity and limited available tissue. In this context, tissue engineering represents a promising alternative approach for the surgical treatment of otolaryngologic disorders. In particular, 3D printing coupled with advanced imaging technologies offers the unique opportunity to reproduce the complex anatomy of native ear, nose, and throat, with its import in terms of functionality as well as aesthetics and the associated patient well-being. In this review, we provide a general overview of the main ear, nose and throat disorders and focus on the most recent scientific literature on 3D printing and bioprinting for their treatment.

Review of Preferential Suspicious Genes in Microtia Patients Through Various Approaches

Recently, an increasing trend of the birth prevalence of anotia/microtia is observed in China, contributed by changes of social environment and lifestyle. There seems to be no major breakthroughs in exact pathogenesis of microtia, though the research results related to molecular genetics unceasingly appear. In this review, the authors focus on the results of various research methods which the authors regard as the preferential suspicious gene pool to facilitate the exploration of the pathogenic genes of microtia, knowing that the mechanism of microtia is very complicated. The advantages and limitations of these various approaches will also be systematically delineated. The authors believe that this review will give a deep insight in the genetic research of microtia and help plastic surgeons manage congenital microtia more effectively.

Genome-wide association study shows that microtia in Altay sheep is caused by a 76 bp duplication of HMX1

Microtia is a congenital malformation of the external ear that can be observed in many species including sheep. However, the genetic basis of microtia still remains unclear. Here, a GWAS was conducted to investigate the genetic basis underlying microtia. A total of 55 samples from 26 microtia and 29 normal animals were genotyped with Illumina OvineHD BeadChip. The strongest significant SNP was identified on OAR6, approximating the evolutionarily conserved region of the HMX1 gene, which is related to congenital malformations of the external ear in other species such as cattle and rats. Sequencing an evolutionarily conserved region surrounding HMX1 revealed a duplication of 76 bp, which is concordant with microtia, suggesting a dominant inheritance mode. Identification of this causal mutation in the HMX1 gene indicates the role of this particular gene in the development of the external ear and provides a genetic marker for selection against microtia.

Risk factors associated with congenital defects that alter hearing or vision in children born in the city of Bogotá between 2002 and 2016

INTRODUCTION

Congenital defects affecting the auditory and visual capacity of newborns represent a public health problem as they result in substantial disability, directly impacting the quality of life of newborns and their families.

OBJECTIVE

To evaluate risk factors associated with congenital defects that alter hearing or vision in newborns in the city of Bogotá between 2002 and 2016.

METHOD

Data from the Bogotá Birth Defects Surveillance and Follow-up Program was used, which consolidated data regarding 167 ECLAMC study (Estudio Colaborativo Latino Americano de Malformaciones Congénitas, in spanish) variables in a case-control design to identify risk factors for birth defects after parents provided signed informed consent. Cases were defined as any newborn (alive or stillborn) with a weight greater than 500 g with any visual or hearing abnormality. Controls were defined as newborn in the same hospital and month with no birth defects. Groups were formed according to the case presentation as follows: isolated eye anomaly, isolated ear anomaly, polymalformative, syndromic, and teratogenic.

RESULTS

In total, 402,657 births were reviewed, of which 968 cases had some congenital defects that alter hearing or vision. An association was found between the presence of defects and prematurity, as well as between syndromic cases and increasing maternal age. When comparing cases and controls with the risk of having a birth defect, multiparity had an odds ratio (OR) of 1.47 (95% CI: 1.27-1.71), acute respiratory infection had an OR of 2.41 (95% CI: 1.04-5.58), low maternal education level had an OR of 1.34 (95% CI:1.10-1.62), low paternal education had an OR of 1.42, (95% CI:1.17-1.73), manual labor in the maternal occupation had an OR of 1.31 (95% CI:1.03-1.67), and a history of congenital anomalies in the family had an OR of 1.55 (95% CI:1.19-2.00).

CONCLUSION

This research allowed the identification of epidemiological data and significant risk factors for congenital defects that alter hearing or vision in the population of Bogotá.

Tissue Engineering Auricular Cartilage Using Late Passage Human Auricular Chondrocytes

PURPOSE

The significant shortcomings associated with current autologous reconstructive options for auricular deformities have inspired great interest in a tissue engineering solution. A major obstacle in the engineering of human auricular cartilage is the availability of sufficient autologous human chondrocytes. A clinically obtainable amount of auricular cartilage tissue (ie, 1 g) only yields approximately 10 million cells, where 25 times this amount is needed for the fabrication of a full-scale pediatric ear. It is thought that repeated passaging of chondrocytes leads to dedifferentiation and loss of the chondrogenic potential. However, little to no data exist regarding the ideal number of times that human auricular chondrocytes (HAuCs) can be passaged in a manner that maximizes the cellular expansion while minimizing dedifferentiation.

METHODS

Human auricular chondrocytes were isolated from discarded otoplasty specimens. The HAuCs were then expanded, and cells from passages 3, 4, and 5 were encapsulated into discs 8 mm in diameter made from type I collagen hydrogels with a cell density of 25 million cells/mL. The constructs were implanted subcutaneously in the dorsa of nude mice and harvested after 1 and 3 months for analysis.

RESULTS

Constructs containing passages 3, 4, and 5 chondrocytes all maintained their original cylindrical geometry. After 3 months in vivo, the diameters of the P3, P4, and P5 discs were 69 ± 9%, 67 ± 10%, and 73 ± 15% of their initial diameter, respectively. Regardless of the passage number, all constructs developed a glossy white cartilaginous appearance, similar to native auricular cartilage. Histologic analysis demonstrated development of an organized perichondrium composed of collagen, a rich proteoglycan matrix, cellular lacunae, and a dense elastin fibrin network by Safranin-O and Verhoeff stain. Biochemical analysis confirmed similar amounts of proteoglycan and hydroxyproline content in late passage constructs when compared with native auricular cartilage.

CONCLUSIONS

These data indicate that late passage HAuCs (up to passage 5) form elastic cartilage that is histologically, biochemically, and biomechanically similar to native human elastic cartilage and have the potential to be used for auricular cartilage engineering.

Reconstruction of Congenital Microtia and Anotia: Analysis of Practitioner Epidemiology and Postoperative Outcomes

BACKGROUND

Microtia refers to a congenital malformation of the external ear that is associated with a range of functional, psychosocial, aesthetic, and financial burdens. The aim of this study was to analyze the epidemiology and postoperative complication profile of microtia reconstruction.

METHODS

A retrospective review was conducted using data from the 2012-2017 the American College of Surgeons National Quality Improvement Program Pediatric databases. Patients with a diagnosis of microtia or anotia were identified using International Classification of Diseases codes. Demographics and postoperative complications were analyzed using Chi-square and t tests for categorical and continuous variables, respectively. Multivariable regression was performed to control for confounding variables.

RESULTS

A total of 466 cases were analyzed, of which 290 (62.2%) were performed by plastic surgeons and 176 (37.8%) by otolaryngologists (ear, nose, and throat physicians [ENT]). Autologous reconstruction was the predominant approach [76.2% of cases (n = 355)] in this cohort. ENT physicians operated on a significantly younger patient population (mean age 8.4 ± 3.2 years versus 10.0 ± 3.2 years, P< 0.001) and had higher rates of concurrent atresia/middle ear repair [21.0% (n = 37) versus 3.7% (n = 17)] compared with plastic surgeons. The rate of all-cause complications was 5.9% (n = 17) in the plastic surgery cohort and 4.0% (n = 7) in the ENT cohort (P= 0.372). Multivariable regression did not reveal any statistically significant predictors for all-cause complications.

CONCLUSIONS

Reconstruction of the external ear for patients with microtia/anotia is a safe procedure, with low rates of postoperative complications, readmissions, and reoperations. Autologous reconstruction remains the preferred modality for repair of the external ear and simultaneous atresiaplasty/middle ear repair does not increase the risk of complications.

Fetal microtia and FGFR2 polymorphism

Association of the single-nucleotide polymorphism (SNP) of rs3135718 site in fibroblast growth factor receptor 2 (FGFR2) gene with congenital microtia was investigated. A total of 193 patients with congenital microtia (observation group) and 150 normal and healthy fetuses (control group) treated in Maternity and Child Health Care of Zaozhuang from January 2010 to October 2017 were randomly selected. The gene and genotype of the rs3135718 site of FGFR2 gene SNP were detected via quantitative polymerase chain reaction (qPCR). The association between rs3135718 site SNP and congenital microtia was analyzed. No statistically significant difference in the prevalence of congenital microtia was observed in the rs3135718 genotype (AG) between the observation and control group (P>0.05). The GG and G genotypes in rs3135718 were closely related to fetal microtia (P<0.05). Results revealed that the rs3135718-GG mutation was more correlated with the risk of microtia in male (P<0.05), but not correlated with the risk of microtia in female (P>0.05). Moreover, there was a statistically significant difference in the distribution of rs3135718-G allele frequency in male between the two groups (P<0.05). The rs3135718-G gene in FGFR2 has a certain association with the incidence of congenital microtia with high prevalence and risk.

Auricular Reconstructive Surgery Improvement to the Firmin Technique for Placing an Earring

Microtia has an incidence of 1 in 7000 to 8000 births. Ear reconstruction has 2 main aims: reconstructive and aesthetic, and a considerable number of patients ask for an earring at the end of their treatment. Herein, we explain our team's modification to the Firmin technique, perforating the lowest part of the autologous cartilage framework (Parri's modification). The orifice is cartilaginous and the skin covering both sides is easily perforable without contacting the rest of the framework. In conclusion, our modification for placing an earring is simple; it does not increase the surgical time and contributes to approach the perfection of auricular reconstructive surgery.

Identification of sequence variants associated with severe microtia-astresia by targeted sequencing

Background

Microtia-atresia is characterized by abnormalities of the auricle (microtia) and aplasia or hypoplasia of the external auditory canal, often associated with middle ear abnormalities. To date, no causal genetic mutations or genes have been identified in microtia-atresia patients.

Methods

We designed a panel of 131 genes associated with external/middle or inner ear deformity. Targeted genomic capturing combined with next-generation sequencing (NGS) was utilized to screen for mutations in 40 severe microtia-atresia patients. Mutations detected by NGS were filtered and validated. And then mutations were divided into three categories—rare or novel variants, low-frequency variants and common variants—based on their frequency in the public database. The rare or novel mutations were prioritized by pathogenicity analysis. For the low-frequency variants and common variants, we used association studies to explore risk factors of severe microtia-atresia.

Results

Sixty-five rare heterozygous mutations of 42 genes were identified in 27 (67.5%) severe microtia-atresia patients. Association studies to determine genes that were potentially pathogenic found that PLEC, USH2A, FREM2, DCHS1, GLI3, POMT1 and GBA genes were significantly associated with severe microtia-atresia. Of these, DCHS1 was strongly suggested to cause severe microtia-atresia as it was identified by both low-frequency and common variants association studies. A rare mutation (c.481C > T, p.R161C) in DCHS1 identified in one individual may be deleterious and may cause severe microtia-atresia.

Conclusion

We identified several genes that were significantly associated with severe microtia-atresia. The findings provide new insights into genetic background of external ear deformities.

Electronic supplementary material

The online version of this article (10.1186/s12920-019-0475-x) contains supplementary material, which is available to authorized users.

Different suturing techniques in thoracic incision: protocol for a feasibility randomised controlled trial

INTRODUCTION

Based on the principles of the ideal skin closure technique, we previously described a suture technique (wedge-shaped excision and modified buried vertical mattress suture (WE-MBVMS)) that could provide excellent outcomes for the most demanding surfaces. However, adequate clinical comparative evidence supporting improved outcomes is lacking. Thus, the purpose of this protocol is to establish the feasibility of conducting a fully randomised controlled trial (RCT) comparing the clinical effectiveness of WE-MBVMS with a buried intradermal suture (BIS) in closing thoracic incision.

METHODS AND ANALYSIS

This study is a feasibility RCT of WE-MBVMS and BIS in patients undergoing surgery for costal cartilage harvesting. Seventy-eight participants are expected to participate in the study and will be randomised in a ratio of 1:1 to WE-MBVMS or BIS. Trial feasibility will be assessed by the number of participants assessed for eligibility, recruitment rates, reasons for ineligibility or non-participation, time for interventions, withdrawal and retention at all follow-up points (3, 6 and 12 months), follow-up rates and reasons for withdrawing from the trial. In addition, clinical data regarding the cosmetic results of scars will be collected to inform the sample size for a fully powered RCT.

ETHICS AND DISSEMINATION

This study has been approved by The First Affiliated Hospital of Xi'an Jiaotong University Institutional Review Board (XJTU1AF2017LSK-120). The findings will be published in peer-reviewed journals.

TRIAL REGISTRATION NUMBER

ChiCTR-INR-17013335; Pre-results.