[Genetic analysis of a Chinese pedigree affected with Branchio-oculo-facial syndrome and a literature review].

OBJECTIVE: To explore the genetic etiology of a Chinese pedigree affected with Branchio-oculo-facial syndrome (BOFS) and summarize the prenatal phenotype of BOFS patients. METHODS: A pedigree with BOFS which had presented at the Genetics and Prenatal Diagnosis Center of the First Affiliated Hospital of Zhengzhou University in December 2021 was selected as the study subject. Clinical data of the pedigree was collected. The fetus was subjected to routine prenatal ultrasound scan. Trio-whole exome sequencing (trio-WES) was carried out for the fetus and its parents, and candidate variant was verified by Sanger sequencing. Relevant literature was searched from the database to summarize the prenatal phenotype of BOFS patients. RESULTS: Ultrasound exam suggested the fetus had cleft lip and palate. Its father had presented with high palatal arch, prematurely grayed hair, occult cleft lip, congenital preauricular fistula, red-green color blindness and unilateral renal agenesis. Its grandfather also had high palatal arch, prematurely gray hair, protruding ears, congenital preauricular fistula and hearing disorders. Trio-WES revealed that the fetus and its father had both harbored a heterozygous c.890-1G>A variant of the TFAP2A gene. The same variant was not found in its mother. Sanger sequencing confirmed that its grandfather had also harbored the same variant. Based on the guidelines from the American College of Medical Genetics and Genomics (ACMG), the variant was rated as likely pathogenic (PVS1+PM2_Supporting). Combined with 36 similar cases retrieved from the literature, the prenatal phenotypes of BOFS patients had included growth restriction (25/37), renal abnormalities (10/37), cleft lip and palate (5/37) and oligohydramnios (5/37). CONCLUSION: The c.890-1G>A variant of the TFAP2A gene probably underlay the pathogenesis of BOFS in this pedigree. Discovery of the novel variant has enriched the mutational spectrum of the TFAP2A gene. The common prenatal phenotypes of BOFS have included growth restriction, renal abnormalities, cleft lip and palate and oligohydramnios. Delineation of the intrauterine phenotype of BOFS may facilitate its prenatal diagnosis, clinical diagnosis, treatment and genetic counseling.

Genomic Landscape of Branchio-Oto-Renal Syndrome through Whole-Genome Sequencing: A Single Rare Disease Center Experience in South Korea.

Branchio-oto-renal (BOR) and branchio-otic (BO) syndromes are characterized by anomalies affecting the ears, often accompanied by hearing loss, as well as abnormalities in the branchial arches and renal system. These syndromes exhibit a broad spectrum of phenotypes and a complex genomic landscape, with significant contributions from the EYA1 gene and the SIX gene family, including SIX1 and SIX5. Due to their diverse phenotypic presentations, which can overlap with other genetic syndromes, molecular genetic confirmation is essential. As sequencing technologies advance, whole-genome sequencing (WGS) is increasingly used in rare disease diagnostics. We explored the genomic landscape of 23 unrelated Korean families with typical or atypical BOR/BO syndrome using a stepwise approach: targeted panel sequencing and exome sequencing (Step 1), multiplex ligation-dependent probe amplification (MLPA) with copy number variation screening (Step 2), and WGS (Step 3). Integrating WGS into our diagnostic pipeline detected structure variations, including cryptic inversion and complex genomic rearrangement, eventually enhancing the diagnostic yield to 91%. Our findings expand the genomic architecture of BOR/BO syndrome and highlight the need for WGS to address the genetic diagnosis of clinically heterogeneous rare diseases.

[Clinical phenotypic and genetic analysis of syndrome families with EYA1 gene variants].

Objective:To investigate the clinical phenotype of a family with branchio-oto syndrome （BOS） and to explore the genetic etiology of the syndrome in this family. Methods:Clinical data were collected from a child diagnosed with BOS and his family members. Genomic DNA was extracted from peripheral blood of the proband and his family members. Whole-exome sequencing was performed, and the mutation sites were verified and analyzed by Sanger sequencing. Results:The family consists of two generations with four members, three of whom exhibit the phenotype. Two members have hearing loss and bilateral preauricular fistulas and bilateral branchial cleft fistulas. One member has bilateral preauricular fistulas and bilateral branchial cleft fistulas. All of which were in line with the clinical diagnosis of gill ear syndrome, the inheritance mode of the family was autosomal dominant inheritance, genetic testing showed that all members of the family had c. 1744delC（p. L592Cfs*47） mutation in the EYA1 gene, while unaffected members have the wild-type allele at this locus. This mutation is a frameshift mutation, which results in the early appearance of the stop codon, and has not been reported so far. According to ACMG guidelines, the variant was preliminarily determined to be suspected pathogenic. Conclusion:The newly discovered EYA1c. 1744delC（p. L592Cfs*47） mutation in this family is the pathogenic mutant gene of the patients in this family, which further expands the mutation spectrum of EYA1 gene, gives us a new understanding of the disease, and provides an important reference for clinical diagnosis and genetic counseling.

Novel likely pathogenic variant in the EYA1 gene causing Branchio oto renal syndrome and the exploration of pathogenic mechanisms.

OBJECTIVE: Branchio-oto-renal syndrome (BOR, OMIM#113,650) is a rare autosomal dominant disorder that presents with a variety of symptoms, including hearing loss (sensorineural, conductive, or mixed), structural abnormalities affecting the outer, middle, and inner ear, branchial fistulas or cysts, as well as renal abnormalities.This study aims to identify the pathogenic variants by performing genetic testing on a family with Branchio-oto-renal /Branchio-otic (BO, OMIM#602,588) syndrome using whole-exome sequencing, and to explore possible pathogenic mechanisms. METHODS: The family spans 4 generations and consists of 9 individuals, including 4 affected by the BOR/BO syndrome. Phenotypic information, including ear malformation and branchial cleft, was collected from family members. Audiological, temporal bone imaging, and renal ultrasound examinations were also performed. Whole-exome sequencing was conducted to identify candidate pathogenic variants and explore the underlying molecular etiology of BOR/BO syndrome by minigene experiments. RESULTS: Intra-familial variability was observed in the clinical phenotypes of BOR/BO syndrome in this family. The severity and nature of hearing loss varied in family members, with mixed or sensorineural hearing loss. The proband, in particular, had profound sensorineural hearing loss on the left and moderate conductive hearing loss on the right. Additionally, the proband exhibited developmental delay, and her mother experienced renal failure during pregnancy and terminated the pregnancy prematurely. Genetic testing revealed a novel heterozygous variant NM_000503.6: c.639 + 3 A > C in the EYA1 gene in affected family members. In vitro minigene experiments demonstrated its effect on splicing. According to the American College of Medical Genetics (ACMG) guidelines, this variant was classified as likely pathogenic. CONCLUSION: This study highlights the phenotypic heterogeneity within the same family, reports the occurrence of renal failure and adverse pregnancy outcomes in a female patient at reproductive age with BOR syndrome, and enriches the mutational spectrum of pathogenic variants in the EYA1 gene.

[Clinical features and temporal CT findings in patients with Branchio-Oto-Renal or Branchio-Oto Syndrome].

Objective: To assess the clinical features and CT diagnostic characteristics of Branchio-Oto-Renal or Branchio-Oto Syndrome. Methods: The temporal CT findings and clinical features observations of 13 patients with Branchio-Oto-Renal Syndrome (BORS) or Branchio-Oto Syndrome(BOS) confirmed by genetic testing were retrospectively analyzed. There were 8 males and 5 females, aged from 1 to 39 years, with a median age of 9 years, in which 3 pairs (6 cases) were parent-child relationship. Results: All of 13 cases had hearing loss and preauricular fistula, 11 cases accompanied by 2nd branchial fistulas. There were 20 ears of mixed hearing loss, 3 ears of sensorineural hearing loss, and 2 ears of conductive hearing loss. The mutation point of gene testing was located in EYA1 in 12 cases and SIX1 in 1 case. Twenty ears showed gradually narrowing of the diameter of basal turn, with hypoplasia in the second turn and aplasia in apical turn. There were irregular wall of vestibule and horizontal semicircular canal in 10 ears,widened vestibular in 7 ears, and vestibular fusion with horizontal semicircular canal in 3 ears. Three ears had an enlarged vestibular aqueduct, 8 ears showed enlargement of internal auditory canal. Seventeen ears had adhesion of malleolus to tympanic cavity. Six ears could not measured the incudostapedial joint angle by reason of tympanic inflammatory cover, 3 ears could not show incudostapedial joint, and 8 ears showed the incudostapedial joint angle more than 122°. Six ears showed poor oval window, and 1 ear had poor round window. Eighteen ears showed distended eustachian tube, and accompanied by tympanic or mastoiditis in 11 ears. Anterolateral shift of tympanum was found in 22 ears, 17 ears had low middle cranial fossa, and 3 ears had stenotic external auditory canal. Conclusions: Cochlear dysplasia, ossicular chain malformation and distended eustachian tube comprise the characteristic CT signs of BOS/BORS, which possesses versatile and complex CT findings. Temporal CT can accurately assess the important structures such as cochlea, ossicles, vestibule, semicircular canal, vestibular aqueduct and internal auditory canal. Combing with the clinical characteristics of bilateral, mixed hearing loss, preauricular fistula and branchial fistula can provide valuable information for early diagnosis and treatment.

Shared features in ear and kidney development - implications for oto-renal syndromes.

The association between ear and kidney anomalies has long been recognized. However, little is known about the underlying mechanisms. In the last two decades, embryonic development of the inner ear and kidney has been studied extensively. Here, we describe the developmental pathways shared between both organs with particular emphasis on the genes that regulate signalling cross talk and the specification of progenitor cells and specialised cell types. We relate this to the clinical features of oto-renal syndromes and explore links to developmental mechanisms.

Identification and Functional Study of Enhancers of EYA1: The Causative Gene of Branchio-Oto-Renal Syndrome.

INTRODUCTION: Branchio-oto-renal syndrome (BOR syndrome) is a rare genetic disorder with an incidence of 1 in 40,000, affecting the development of multiple organs, including the branchio, ear, and kidney. It is responsible for 2% of childhood deafness. Currently, variants in the coding regions of the main causative genes, such as EYA1, SIX1, and SIX5, explain only half of the disease's etiology. Therefore, there is a need to explore the non-coding regions, which constitute the majority of the genome, especially the regulatory regions, as potential new causative factors. METHOD: In this study, we focused on the EYA1 gene, which accounts for over 40% of BOR syndrome cases, and conducted a screening of candidate enhancers within a 250-kb region upstream and downstream of the gene using comparative genomics. We characterized the enhancer activities of these candidates in zebrafish using the Tol2 transposon system. RESULTS: Our findings revealed that out of the 11 conserved non-coding elements (CNEs) examined, four exhibited enhancer activity. Notably, CNE16.39 and CNE16.45 displayed tissue-specific enhancer activity in the ear. CNE16.39 required the full-length 206 bp sequence for inner-ear-specific expression, while the core functional region of CNE16.45 was identified as 136 bp. Confocal microscopy results demonstrated that both CNE16.39 and CNE16.45 drove the expression of GFP in the sensory region of the crista of the inner ear in zebrafish, consistent with the expression pattern of eya1. CONCLUSION: This study contributes to the understanding of the regulatory network governing EYA1 expression and offers new insights to further clarify the pathogenic role of EYA1 in BOR syndrome.

A new point mutation (D1158N) in histidine kinase Bos1 confers high-level resistance to fludioxonil in field gray mold disease.

Gray mold, caused by the fungus Botrytis cinerea, is one of the most important plant diseases worldwide that is prone to developing resistance to fungicides. Currently, the phenylpyrrole fungicide fludioxonil exhibits excellent efficacy in the control of gray mold in China. In this study, we detected the fludioxonil resistance of gray mold disease in Shouguang City of Shandong Province, where we first found fludioxonil-resistant isolates of B. cinerea in 2014. A total of 87 single spore isolates of B. cinerea were obtained from cucumbers in greenhouse, and 3 of which could grow on PDA plates amended with 50 µg/mL fludioxonil that was defined as high-level resistance, with a resistance frequency of 3.4%. Furthermore, the 3 fludioxonil-resistant isolates also showed high-level resistance to the dicarboximide fungicides iprodione and procymidone. Sequencing comparison revealed that all the 3 fludioxonil-resistant isolates had a point mutation at codon 1158, GAC (Asp) â†’ AAC (Asn) in the histidine kinase Bos1, which was proved to be the reason for fludioxonil resistance. In addition, the fludioxonil-resistant isolates possessed an impaired biological fitness compared to the sensitive isolates based on the results of mycelial growth, conidiation, virulence, and osmotic stress tolerance determination. Taken together, our results indicate that the high-level resistance to fludioxonil caused by the Bos1 point mutation (D1158N) has emerged in the field gray mold disease, and the resistance risk is relatively high, and fludioxonil should be used sparingly.

A neonatal case report of branchiooculofacial syndrome caused by a novel mutation in the TFAP2A gene and literature review.

RATIONALE: Branchiooculofacial syndrome (BOFS) is a rare autosomal dominant disorder with a diverse clinical phenotype. To summarise the clinical characteristics and genetic variations of neonatal-onset BOFS through a case study and literature review. PATIENT CONCERNS: A preterm neonate with a very low birth weight, born at a gestational age of 29+3 weeks, exhibited cosmetic abnormalities at a postmenstrual age of 34+6 weeks, including microcleft lip, high arched palate, curved upper lip, low ear position, and ocular hypertelorism. Hence, a genetic test on peripheral blood was carried out. DIAGNOSES: The genetic testing showed a heterozygous variant of c.724G > A (p.Glu242Lys) in the exon 4 region of the TFAP2A (transcription factor AP-2-α) gene in the short arm of chromosome 6. BOFS was confirmed based on clinical appearance and the genetic result. INTERVENTIONS: The patient underwent solely cleft lip repair at the age of 6 months with no further intervention. OUTCOMES: The infant shows normal growth and development at 1 year of age and subsequent follow-up. LESSONS: The characteristic facial features, branchial skin defects, and ocular anomalies are the main clinical manifestations of BOFS with neonatal onset, but the diverse clinical phenotype and variable genetic variants pose certain challenges for clinical diagnosis.

A Novel Truncating Mutation in PAX1 Gene Causes Otofaciocervical Syndrome Without Immunodeficiency.

Otofaciocervical syndrome (OTFCS) is a rare genetic disorder of both autosomal recessive and autosomal dominant patterns of inheritance. It is caused by biallelic or monoallelic mutations in PAX1 or EYA1 genes, respectively. Here, we report an OTFCS2 female patient of 1st consanguineous healthy parents. She manifested facial dysmorphism, hearing loss, intellectual disability (ID), and delayed language development (DLD) as the main clinical phenotype. The novel homozygous variant c.1212dup (p.Gly405Argfs*51) in the PAX1 gene was identified by whole exome sequencing (WES), and family segregation confirmed the heterozygous status of the mutation in the parents using the Sanger sequencing. The study recorded a novel PAX1 variant representing the sixth report of OTFCS2 worldwide and the first Egyptian study expanding the geographic area where the disorder was confined.

Misdiagnosed Branchio-Oto-Renal syndrome presenting as proteinuria and renal insufficiency with insidious signs since early childhood: a report of three cases.

BACKGROUND: Branchio-oto-renal (BOR) syndrome is an inherited multi-systemic disorder. Auricular and branchial signs are highly suggestive of BOR syndrome but often develop insidiously, leading to a remarkable misdiagnosis rate. Unlike severe morphological abnormalities of kidneys, knowledge of glomerular involvement in BOR syndrome were limited. CASE PRESENTATION: Three cases, aged 8 ~ 9 years, visited pediatric nephrology department mainly for proteinuria and renal insufficiency, with 24-h proteinuria of 23.8 ~ 68.9 mg/kg and estimated glomerular filtration rate of 8.9 ~ 36.0 mL/min/1.73m2. Moderate-to-severe albuminuria was detected in case 1, while mixed proteinuria was detected in case 2 and 3. Insidious auricular and branchial fistulas were noticed, all developing since early childhood but being neglected previously. EYA1 variants were confirmed by genetic testing in all cases. Delay in diagnosis was 8 ~ 9 years since extra-renal appearances, and 0 ~ 6 years since renal abnormalities. In case 1, therapy of glucocorticoid and immunosuppressive agents to accompanying immune-complex mediated glomerulonephritis was unsatisfying. CONCLUSIONS: BOR syndrome is a rare cause of proteinuria and abnormal kidney function and easily missed, thus requiring more awareness. Careful medical history taking and physical examination are essential to early diagnosis. Massive proteinuria was occasionally seen in BOR syndrome, which might be related to immune complex deposits. A novel pathogenic variant (NM_000503.6 (EYA1): c.1171delT p.Ser391fs*9) was firstly reported.

Phenotypic and molecular basis of SIX1 variants linked to non-syndromic deafness and atypical branchio-otic syndrome in South Korea.

Branchio-oto-renal (BOR)/branchio-otic (BO) syndrome is a rare disorder and exhibits clinically heterogenous phenotypes, marked by abnormalities in the ear, branchial arch, and renal system. Sporadic cases of atypical BOR/BO syndrome have been recently reported; however, evidence on genotype-phenotype correlations and molecular mechanisms of those cases is lacking. We herein identified five SIX1 heterozygous variants (c.307dupC:p.Leu103Profs*51, c.373G>A:p.Glu125Lys, c.386_391del:p.Tyr129_Cys130del, c.397_399del:p.Glu133del, and c.501G>C:p.Gln167His), including three novel variants, through whole-exome sequencing in five unrelated Korean families. All eight affected individuals with SIX1 variants displayed non-syndromic hearing loss (DFNA23) or atypical BO syndrome. The prevalence of major and minor criteria for BOR/BO syndrome was significantly reduced among individuals with SIX1 variants, compared to 15 BOR/BO syndrome families with EYA1 variants. All SIX1 variants interacted with the EYA1 wild-type; their complexes were localized in the nucleus except for the p.Leu103Profs*51 variant. All mutants also showed obvious but varying degrees of reduction in DNA binding affinity, leading to a significant decrease in transcriptional activity. This study presents the first report of SIX1 variants in South Korea, expanding the genotypic and phenotypic spectrum of SIX1 variants, characterized by DFNA23 or atypical BO syndrome, and refines the diverse molecular aspects of SIX1 variants according to the EYA1-SIX1-DNA complex theory.

Molecular Genetic Etiology and Revisiting the Middle Ear Surgery Outcomes of Branchio-Oto-Renal Syndrome: Experience in a Tertiary Referral Center.

OBJECTIVES: To explore the phenotypes and genotypes of patients with branchio-oto-renal (BOR) and branchio-otic (BO) syndrome, and to analyze the middle ear surgery outcomes qualitatively and quantitatively, proposing a factor usefully prognostic of surgical outcomes. STUDY DESIGN: Retrospective cohort study. SETTING: Tertiary referral center. PATIENTS: Eighteen patients with BOR/BO syndrome in 12 unrelated Korean families. INTERVENTION: Middle ear surgery, including either stapes surgery or ossicular reconstruction. MAIN OUTCOME MEASURE: Clinical phenotypes, genotypes, and middle ear surgery outcomes. RESULTS: Eight probands (66.7%) were confirmed genetically; the condition segregated as a dominant or de novo trait. Six EYA1 heterozygous variants were identified by exome sequencing and multiplex ligation-dependent probe amplification. All variants were pathogenic or likely pathogenic based on the ACMG/AMP guidelines. Two novel EYA1 frameshift variants (p.His373Phefs*4 and p.Gln543Asnfs*90) truncating a highly conserved C-terminal Eya domain were identified, expanding the genotypic spectrum of EYA1 in BOR/BO syndrome. Remarkably, middle ear surgery was individualized to ensure optimal audiological outcomes and afforded significant audiological improvements, especially in BOR/BO patients without enlarged vestibular aqueducts (EVAs). A significant difference in air-bone gap closure after middle ear surgery was noted between the two groups even after adjusting for confounders: -20.5 dB in ears without EVAs (improvement) but 0.8 dB in ears with EVAs (no change or deterioration). Furthermore, the success rate was significantly associated with the absence of EVA. CONCLUSIONS: The results of this study were against the notion that middle ear surgery is always contraindicated in patients with BOR/BO syndrome, and an EVA could be a negative prognostic indicator of middle ear surgery in BOR/BO patients. This may aid to determine the strategy of audiological rehabilitation in patients with BOR/BO syndrome.

Dysfunction of programmed embryo senescence is linked to genetic developmental defects.

Developmental senescence is a form of programmed senescence that contributes to morphogenesis during embryonic development. We showed recently that the SIX1 homeoprotein, an essential regulator of organogenesis, is also a repressor of adult cellular senescence. Alterations in the SIX/EYA pathway are linked to the human branchio-oto-renal (BOR) syndrome, a rare congenital disorder associated with defects in the ears, kidneys and branchial arches. Here, we have used Six1-deficient mice, an animal model of the BOR syndrome, to investigate whether dysfunction of senescence underpins the developmental defects associated with SIX1 deficiency. We have focused on the developing inner ear, an organ with physiological developmental senescence that is severely affected in Six1-deficient mice and BOR patients. We show aberrant levels and distribution of senescence markers in Six1-deficient inner ears concomitant with defective morphogenesis of senescent structures. Transcriptomic analysis and ex vivo assays support a link between aberrant senescence and altered morphogenesis in this model, associated with deregulation of the TGFß/BMP pathway. Our results show that misregulation of embryo senescence may lead to genetic developmental disorders, significantly expanding the connection between senescence and disease.

UNC45A-related osteo-oto-hepato-enteric syndrome in a Chinese neonate.

Unexplained diarrhea and cholestasis are common clinical phenotypes in newborns, indicating there is only a little common genetic basis for these conditions. However, it has been reported that defects in the UNC45A gene can lead to osteo-oto-hepato-enteric syndrome. However, to date, only 10 patients with this syndrome have been reported in 2 studies; therefore, there is still a lack of analysis regarding the correlation between disease phenotype and genotype. Trio-whole exome sequencing was conducted using DNA samples from a newborn with congenital diarrhea and cholestasis from a Chinese Han family. The UNC45A variants were verified using Sanger sequencing. In addition, we applied a crystal structure model to analyze the potential hazards associated with the variants. The plasmids were constructed in vitro and transfected into human 293T cells for Western blot (WB) analysis. After the mutant protein was fused with the Green Fluorescent Protein label, intracellular localization was observed using laser confocal microscopy. The gene detection results showed that the UNC45A gene of the newborn examined in the present study harbored the compound heterozygous variants p.Arg819Ter, and p.Leu237Pro; this was confirmed via Sanger sequencing. Analysis of the Leu237Pro crystal structure model suggested that this variant may decrease local structural stability and affect protein function. The Western blot and laser confocal microscopy observation results suggested that the Leu237Pro mutation leads to reduced protein expression, while the Arg819Ter mutation completely inhibits the expression of the protein. The compound heterozygous variants of UNC45A (p.Arg819Ter and p.Leu237Pro) may be pathogenic factors of congenital diarrhea and cholestasis in this neonatal patient. Therefore, UNC45A deficiency should be considered when intractable diarrhea and cholestasis occur in newborns.

An infant with congenital heart defects and proteinuria: a case report.

BACKGROUND: Branchio-Oto-Renal (BOR) Syndrome is a rare autosomal disorder with a wide variety of clinical manifestations and a high degree of heterogeneity. Typical clinical manifestations of BOR syndrome include deafness, preauricular fistula, abnormal gill slits, and renal malformations. However, atypical phenotypes such as congenital hip dysplasia, congenital heart anomaly or facial nerve paresis are rare in BOR syndrome, and this might be easily misdiagnosed with other congenital disorders. CASE PRESENTATION: We report a 5-month-old boy of BOR syndrome with "congenital heart defects and proteinuria" as clinical features. Initially, as this case mainly presented with symptoms of recurrent respiratory infections and was found to be with congenital heart disease and proteinuria at the local hospital, but he only was diagnosed with congenital heart disease combined with pulmonary infection and anti-infective and supportive treatment was given. Subsequently, during the physical examination at our hospital, left side preauricular pit and branchial fistulae on the right neck were found. Subsequent evaluation of auditory brainstem response and distortion product otoacoustic emission were revealed sensorineural hearing impairment. Results of renal ultrasonography showed small kidneys. Genetic analysis revealed a microdeletion at chromosome 8q13.2-q13.3 encompassing EYA1 gene, this patient was finally diagnosed with BOR syndrome. Then, this patient received transcatheter patent ductus arteriosus closure and hearing aid treatment. Proteinuria, renal function and hearing ability are monitoring by nephrologist and otologist. The patient is currently being followed up until 3 months after discharge and his condition is stable. CONCLUSION: Careful physical examination, detailed history and the implementation of diagnostic laboratory tests can reduce the incidence of misdiagnosis. Genetic sequencing analysis of patients is a key guide to the differential diagnosis of BOR syndrome.

Prenatal diagnosis and genetic analysis of a fetus with Branchio-oto-renal syndrome: A case report.

BACKGROUND: Branchio-oto-renal (BOR) syndrome is an autosomal-dominant disorder characterized by branchial arch anomalies, hearing loss, and kidney defects. Mutations in the human EYA1 gene have been reported associated with BOR syndrome. Here we identified that a novel variant, EYA1: NM_000503.4: c.827-1G > C (Intron 8, shear mutation) was associated with BOR in a fetus of a Chinese family. CASE PRESENTATION: Prenatal ultrasound examination showed that both kidneys of the fetus were small and the echo of both kidneys was enhanced. The amount of amniotic fluid was normal, and no other structural abnormalities of the fetus were found. Fetal umbilical cord blood puncture was performed. No abnormality was found in karyotyping and chromosomal microarray analysis (CMA) results. Thus, we performed a trio-based whole exome sequencing (WES), and found that the fetus carried a novel homozygous variant, EYA1: NM_000503.4: c.827-1G > C (Intron 8, shear mutation), but the parents do not have this mutation. The variation sites of fetus and parents were verified by Sanger sequencing to clarify the source of pathogenic variation. CONCLUSION: Combined with fetal imaging examination, the novel variation of EYA1: NM_000503.4: c.827-1G > C is the cause of fetal renal dysplasia. This case report indicates that the early use of appropriate technology can clarify the etiology of fetal disease and guide prognosis consultation.

From clinical to molecular diagnosis: relevance of diagnostic strategy in two cases of branchio-oto-renal syndrome - case report.

BACKGROUND: Branchio-oto-renal syndrome (BOR) is an autosomal dominant disorder characterized by deafness, branchiogenic malformations and renal abnormalities. Pathogenic variants in EYA1, SIX1 and SIX5 genes cause almost half of cases; copy number variants (CNV) and complex genomic rearrangements have been revealed in about 20% of patients, but they are not routinely and commonly included in the diagnostic work-up. CASE PRESENTATION: We report two unrelated patients with BOR syndrome clinical features, negative sequencing for BOR genes and the identification of a 2.65 Mb 8q13.2-13.3 microdeletion. CONCLUSIONS: We highlight the value of CNV analyses in high level of suspicion for BOR syndrome but negative sequencing for BOR genes and we propose an innovative diagnostic flow-chart to increase current detection rate. Our report confirms a mechanism of non-allelic homologous recombination as causing this recurrent 8q13.2-13.3 microdeletion. Moreover, considering the role of PRDM14 and NCOA2 genes, both involved in regulation of fertility and deleted in our patients, we suggest the necessity of a longer follow-up to monitor fertility issues or additional clinical findings.

The Cochlea in Branchio-Oto-Renal Syndrome: An Objective Method for the Diagnosis of Offset Cochlear Turns.

BACKGROUND AND PURPOSE: An "unwound" or "offset" cochlea has been described as a characteristic imaging feature in patients with branchio-oto-renal syndrome, and recently recognized to be associated in particular to those with EYA1 gene mutations. Determination of this feature has traditionally relied on subjective visual assessment. Our aim was to establish an objective assessment method for cochlear offset (the cochlear turn alignment ratio) and determine an optimal cutoff turn alignment ratio value that separates individuals with EYA1-branchio-oto-renal syndrome from those with SIX1-branchio-oto-renal syndrome and healthy controls. MATERIALS AND METHODS: Temporal bone CT or MR imaging from 40 individuals with branchio-oto-renal syndrome and 40 controls was retrospectively reviewed. Cochlear offset was determined visually by 2 independent blinded readers and then quantitatively via a standardized technique yielding the cochlear turn alignment ratio. The turn alignment ratio values were compared between cochleae qualitatively assessed as "not offset" and "offset." Receiver operating characteristic analysis was used to determine the ability of the turn alignment ratio to differentiate between these populations and an optimal cutoff turn alignment ratio value. Cochlear offset and turn alignment ratio values were analyzed for each branchio-oto-renal syndrome genotype subpopulation and for controls. RESULTS: The turn alignment ratio can accurately differentiate between cochleae with and without an offset (P < .001). The optimal cutoff value separating these populations was 0.476 (sensitivity = 1, specificity = 0.986, J = 0.986). All except 1 cochlea among the EYA1-branchio-oto-renal syndrome subset and all with unknown genotype branchio-oto-renal syndrome had a cochlear offset and a turn alignment ratio of <0.476. All except 1 cochlea among the SIX1-branchio-oto-renal syndrome subset and all controls had no offset and a turn alignment ratio of >0.476. CONCLUSIONS: There is a statistically significant difference in turn alignment ratios between offset and nonoffset cochleae, with an optimal cutoff of 0.476. This cutoff value allows excellent separation of EYA1-branchio-oto-renal syndrome from SIX1-branchio-oto-renal syndrome and from individuals without branchio-oto-renal syndrome or sensorineural hearing loss. The turn alignment ratio is a reliable and objective metric that can aid in the imaging evaluation of branchio-oto-renal syndrome.