Search

3D-high efficiency video coding (3D-HEVC) provides great improvements in coding efficiency of multiview texture image and associated depth map. It inherits the prediction mode of HEVC, and several new coding tools for a better representation of the dependent texture and depth video are also employed by the 3D-HEVC encoder. These give a high coding efficiency, but require significantly high runtime due to huge complexity of mode decision. In this paper, we introduce a content-adaptive mode decision to reduce 3D-HEVC coding complexity. The basic idea of this method is to use the temporal-spatial, inter-view and texture-depth correlations to analyze content properties of treeblock, and adaptive skip some unnecessary prediction modes. Experimental results demonstrate that the proposed scheme can drastically save encoding time with no noticeable loss of rate distortion (RD) performance. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the clinical validity of preimplantation genetic testing (PGT) to prevent hereditary hearing loss (HL) in Chinese population. Methods: A PGT procedure combining multiple annealing and looping-based amplification cycles (MALBAC) and single-nucleotide polymorphisms (SNPs) linkage analyses with a single low-depth next-generation sequencing run was implemented. Forty-three couples carried pathogenic variants in autosomal recessive non-syndromic HL genes, GJB2 and SLC26A4, and four couples carried pathogenic variants in rare HL genes: KCNQ4, PTPN11, PAX3, and USH2A were enrolled. Results: Fifty-four in vitro fertilization (IVF) cycles were implemented, 340 blastocysts were cultured, and 303 (89.1%) of these received a definite diagnosis of a disease-causing variant testing, linkage analysis and chromosome screening. A clinical pregnancy of 38 implanted was achieved, and 34 babies were born with normal hearing. The live birth rate was 61.1%. Conclusions and relevance: In both the HL population and in hearing individuals at risk of giving birth to offspring with HL in China, there is a practical need for PGT. The whole genome amplification combined with NGS can simplify the PGT process, and the efficiency of PGT process can be improved by establishing a universal SNP bank of common disease-causing gene in particular regions and nationalities. This PGT procedure was demonstrated to be effective and lead to satisfactory clinical outcomes. [ABSTRACT FROM AUTHOR]

Waardenburg syndrome (WS) is a rare inherited autosomal dominant disorder caused by SOX10, PAX3, MITF, EDNRB, EDN3, and SNAI2. A large burden of pathogenic de novo variants is present in patients with WS, which may be derived from parental mosaicism. Previously, we retrospectively analyzed 90 WS probands with family information. And the frequency of de novo events and parental mosaicism was preliminary investigated in our previous study. In this study, we further explored the occurrence of low-level parental mosaicism in 33 WS families with de novo variants and introduced our procedure of quantifying low-level mosaicism. Mosaic single nucleotide polymorphisms (SNPs) were validated by amplicon-based next-generation sequencing (NGS); copy-number variants (CNVs) were validated by droplet-digital polymerase chain reaction (ddPCR). Molecular validation of low-level mosaicism of WS-causing variants was performed in four families (12.1%, 4/33). These four mosaic variants, comprising three SNVs and one CNV, were identified in SOX10. The rate of parental mosaicism was 25% (4/16) in WS families with de novo SOX10 variants. The lowest allele ratio of a mosaic variant was 2.0% in parental saliva. These de novo WS cases were explained by parental mosaicism conferring an elevated recurrence risk in subsequent pregnancies of parents. Considering its importance in genetic counseling, low-level parental mosaicism should be systematically investigated by personalized sensitive testing. Amplicon-based NGS and ddPCR are recommended to detect and precisely quantify the mosaicism for SNPs and CNVs. [ABSTRACT FROM AUTHOR]

Purpose: To review the resections of endolymphatic sac tumor (ELST) and describe our experience in the surgical management of ELST. Methods: Retrospective investigation of consecutive patients who underwent resection of ELSTs at our hospital between 1999 and 2019. The symptoms, diagnosis, surgical findings, and outcomes were analyzed to develop a tumor staging system and corresponding surgical strategy. Results: Retrospective review revealed the surgical treatment of 22 ELSTs. Based on intraoperative findings of tumor extent and size, ELSTs were classified into two types. Type-I (n = 6) referred to the small tumors that were locally confined with limited invasion of semicircular canals and dura; type-II (n = 16) referred to the large tumors that presented extensive erosion of at least one anatomic structure apart from the semicircular canals and the dura around endolymphatic sac. In this case series, Type-I ELST is amenable to resection through a transmastoidal approach, and subtotal petrosectomy is appropriate for the resection of type-II ELST. Sensorineural hearing loss (SNHL) is the most commonly preoperative symptom in both two types of cases. Five type-II ELSTs experienced recurrence and underwent reoperation, whereas all type-I ELSTs did not. Conclusion: ELST usually results in SNHL (95%) at the time of diagnosis. The surgical strategy and prognosis of ELST resections are different between type-I and type-II: type-I ELST is amenable to transmastoidal approach with the preservation of facial nerve, whereas type-II ELST increase the surgical difficulty and the risk of recurrence, and subtotal petrosectomy is the basic requirement for the resection of type-II ELST. [ABSTRACT FROM AUTHOR]

Purpose: To demonstrate our experience in the treatment of petrous bone cholesteatoma (PBC). Methods: Data of PBC patients in our hospital from January 2000 to December 2019 were collected. Surgical approaches and facial function were mainly discussed and compared with the literature. The management of 2 giant PBC cases affecting rhinopharynx has been demonstrated. Results: The supralabyrinthine type was the most frequent type followed by the massive type. There were 5 cases with cholesteatoma extending into the clivus (2 cases), sphenoid (1 case) and rhinopharynx (2 cases). The translabyrinthine approach (40%) was our most frequently used approach followed by the middle fossa approach (36%) and the transmastoid approach (11%). There were 10 cases managed with the assistance of endoscope, including 3 cases with cholesteatoma extending into clivus, sphenoid and rhinopharynx separately. Obliteration of the cavity was performed in 70.3% (135/192) cases; 3 of them recurred. For the 2 giant PBC cases affecting rhinopharynx, traditional microscopic surgery assisted with transnasal endoscope was performed. The reduced exposure was beneficial for postoperative recovery, and the approach in the nasal cavity provided a permanent drainage for postoperative examination. Conclusion: Otologic endoscope combined with traditional microscopic surgery could reduce the exposure in surgery. For extremely extended cases of PBC, supplementary transnasal endoscopic approach deserves to be considered for the traditional temporal bone approach. [ABSTRACT FROM AUTHOR]

Deafness and onychodystrophy syndromes are a group of phenotypically overlapping syndromes, which include DDOD syndrome (dominant deafness-onychodystrophy), DOORS syndrome (deafness, onychodystrophy, osteodystrophy, mental retardation and seizures) and Zimmermann–Laband syndrome (gingival hypertrophy, coarse facial features, hypoplasia or aplasia of nails and terminal phalanges, intellectual disability, and hypertrichosis). Pathogenic variants in four genes, ATP6V1B2, TBC1D24, KCNH1 and KCNN3, have been shown to be associated with deafness and onychodystrophy syndromes. ATP6V1B2 encodes a component of the vacuolar H+-ATPase (V-ATPase) and TBC1D24 belongs to GTPase-activating protein, which are all involved in the regulation of membrane trafficking. The overlapping clinical phenotype of TBC1D24- and ATP6V1B2- related diseases and their function with GTPases or ATPases activity indicate that they may have some physiological link. Variants in genes encoding potassium channels KCNH1 or KCNN3, underlying human Zimmermann–Laband syndrome, have only recently been recognized. Although further analysis will be needed, these findings will help to elucidate an understanding of the pathogenesis of these disorders better and will aid in the development of potential therapeutic approaches. In this review, we summarize the latest developments of clinical features and molecular basis that have been reported to be associated with deafness and onychodystrophy disorders and highlight the challenges that may arise in the differential diagnosis. [ABSTRACT FROM AUTHOR]

Pathogenic variations in the OTOF gene are a common cause of hearing loss. To refine the natural history and genotype–phenotype correlations of OTOF-related auditory neuropathy spectrum disorders (ANSD), audiograms and distortion product otoacoustic emissions (DPOAEs) were collected from a diverse cohort of individuals diagnosed with OTOF-related ANSD by comprehensive genetic testing and also reported in the literature. Comparative analysis was undertaken to define genotype–phenotype relationships using a Monte Carlo algorithm. 67 audiograms and 25 DPOAEs from 49 unique individuals positive for OTOF-related ANSD were collected. 51 unique OTOF pathogenic variants were identified of which 21 were missense and 30 were loss of function (LoF; nonsense, splice-site, copy number variants, and indels). There was a statistically significant difference in low, middle, and high frequency hearing thresholds between missense/missense and LoF/missense genotypes as compared to LoF/LoF genotypes (average hearing threshold for low, middle and high frequencies 70.9, 76.0, and 73.4 dB vs 88.5, 95.6, and 94.7 dB) via Tukey's test with age as a co-variate (P = 0.0180, 0.0327, and 0.0347, respectively). Hearing declined during adolescence with missense/missense and LoF/missense genotypes, with an annual mid-frequency threshold deterioration of 0.87 dB/year and 1.87 dB/year, respectively. 8.5% of frequencies measured via DPOAE were lost per year in individuals with serial tests. Audioprofiling of OTOF-related ANSD suggests significantly worse hearing with LoF/LoF genotypes. The unique pattern of variably progressive OTOF-related autosomal recessive ANSD may be amenable to gene therapy in selected clinical scenarios. [ABSTRACT FROM AUTHOR]

Waardenburg syndrome (WS) is a phenotypically and genetically heterogeneous disorder characterised by hearing loss and pigmentary abnormalities. We clarified the clinical and genetic features in 90 Chinese WS probands. Disease-causing variants were detected in 55 probands, for a molecular diagnosis rate of 61%, including cases related to PAX3 (14.4%), MITF (24.4%), and SOX10 (22.2%). Altogether, 48 variants were identified, including 44 single-nucleotide variants and 4 copy number variants. By parental genotyping, de novo variants were observed in 60% of probands and 15.4% of the de novo variation was associated with mosaicism. Statistical analyses revealed that brown freckles on the skin were more frequently seen in probands with MITF variants; patchy depigmented skin, asymmetric hearing loss, and white forelocks occurred more often in cases with PAX3 variants; and congenital inner ear malformations were more common and cochlear hypoplasia III was exclusively observed in those with SOX10 variants. In addition, we found that ranges of W-index values overlapped between WS probands with different genetic variants, and the use of the W-index as a tool for assessing dystopia canthorum may be problematic in Chinese. Herein, we report the spectrum of a cohort of WS probands and elucidate the relationship between genotype and phenotype. [ABSTRACT FROM AUTHOR]

A letter to the editor is presented in response to the article "De novo mutation in ATP6V1B2 impairs lysosome acidification and causes dominant deafness-onychodystrophy syndrome" in the June 10, 2014 issue.

The myosin VIIA (MYO7A) gene encodes a protein classified as an unconventional myosin. Mutations within MYO7A can lead to both syndromic and non-syndromic hearing impairment in humans. Among different mutations reported in MYO7A, only five led to non-syndromic sensorineural deafness autosomal dominant type 11 (DFNA11). Here, we present the clinical, genetic and molecular characteristics of two large Chinese DFNA11 families with either high- or low-frequency hearing loss. Affected individuals of family DX-J033 have a sloping audiogram at young ages with high frequency are most affected. With increasing age, all test frequencies are affected. Affected members of family HB-S037 present with an ascending audiogram affecting low frequencies at young ages, and then all frequencies are involved with increasing age. Genome-wide linkage analysis mapped the disease loci within the DFNA11 interval in both families. DNA sequencing of MYO7A revealed two novel nucleotide variations, c.652G>A (p.D218N) and c.2011G>A (p.G671S), in the two families. It is for the first time that the mutations identified in MYO7A in the present study are being implicated in DFNA11 in a Chinese population. For the first time, we tested electrocochleography (ECochG) in a DFNA11 family with low-frequency hearing loss. We speculate that the low-frequency sensorineural hearing loss in this DFNA11 family was not associated with endolymphatic hydrops. [ABSTRACT FROM AUTHOR]

Deafness is an etiologically heterogeneous trait with many known genetic, environmental causes or a combination thereof. The identification of more than 120 independent genes for deafness has provided profound new insights into the pathophysiology of hearing. However, recent findings indicate that a large proportion of both syndromic and non-syndromic forms of deafness in the Chinese population are caused by defects in a small number of genes. Studies of the genetic epidemiology and molecular genetic features revealed that there is a clear relevance of genes causing deafness in Chinese deaf patients as well as a unique spectrum of common and rare deafness gene mutations in the Chinese population. This review is focused on the genetic aspects of non-syndromic and mitochondrial deafness, in which unique molecular genetic features of hearing impairment have been identified in the Chinese population. The current China population is approximately 1.3 billion. It is estimated that 30 000 infants are born with congenital sensorineural hearing loss each year. Better understanding of the genetic causes of deafness in the Chinese population is important for accurate genetics counseling and early diagnosis for timely intervention and treatment options.Journal of Human Genetics (2009) 54, 131–140; doi:10.1038/jhg.2009.4; published online 6 February 2009 [ABSTRACT FROM AUTHOR]