Cadherins ; genetics ; Hearing Loss, Sensorineural ; genetics ; pathology ; Humans

Hearing loss is one of the most common sensory disorders and has numerous environmental and genetic factors that influence its onset and development. Hearing loss can be classified by either the affected anatomic or functional lesion of hearing loss, or as conductive or sensorineural hearing loss (SNHL). Genetic factors account for about 50% of congenital SNHL, and are therefore the most common cause. Molecular genetics research has identified more than 100 genes related to hearing and hearing loss, and shown that the risk of hearing loss caused by non-genetic factor is modified by genetic susceptibility. About 30% of genetic hearing loss is syndromic related and has affected phenotypic markers in other organs that make it easier to correctly diagnose the etiology of the hearing loss. In some cases, hearing loss can precede the pathologies of other organs and in these cases, hearing loss acts as a predictor of the syndrome associated pathologies of other organs. Inheritance of nonsyndromic hearing loss follows common inheritance patterns such as autosomal dominant, autosomal recessive, sex chromosome related, and mitochondrial inheritances. The paucity of predominant phenotypes and ethnic specificity of the prevalence and types of mutations may hinder the genetic diagnosis in nonsyndromic hearing loss. However, progress in elucidating the causal mutations is going forward using stratified genetic diagnostic strategies of candidate genes identified by hearing phenotypes and patterns of inheritance.
Diagnosis ; Fibrinogen ; Genetic Predisposition to Disease ; Genetics ; Hearing ; Hearing Loss* ; Hearing Loss, Sensorineural ; Inheritance Patterns ; Molecular Biology ; Pathology ; Phenotype ; Prevalence ; Risk Factors ; Sensation Disorders ; Sensitivity and Specificity ; Sex Chromosomes ; Wills

Although the basic principles for the function of peripheral auditory system have been known for many years, the molecular mechanisms which affect deafness are not clear. In recent years, the study of hereditary deafness associated mouse models has revealed the molecular basis which is related with the formation and function of the hair bundle and the mechanosensory organelle of hair cell. This review focused on the role of protein network, which is formed by the proteins encoded by the Usher syndrome type 1 genes, in hair-bundle development and mechanotransducer channel gating. And the review also showed how the stereocilia rootlets contribute to the hair bundle's mechanical properties and how the hair bundle produces suppressive masking. Finally, the review revealed multiple roles of the tectorial membrane and extracellular matrix in the hair bundles stimulating in the cochlea.
Animals ; Cochlea ; physiopathology ; Disease Models, Animal ; Extracellular Matrix ; physiology ; Hair Cells, Auditory ; pathology ; Hearing Loss, Sensorineural ; genetics ; Humans ; Mechanotransduction, Cellular ; Mice ; Usher Syndromes ; genetics

Objective:To study the frequency of SLC26A4 gene mutation sites in children with enlarged vestibular aqueduct deafness in Yunnan, report the new mutation sites of SLC26A4 gene, further clarify the mutation spectrum of SLC26A4gene, and explore the association between biallelic and monoallelic mutations of SLC26A4 gene and CT phenotype of inner ear, so as to provide basis for clinical and genetic diagnosis of deafness. Methods:Review the results of temporal bone CT examination of 390 children after cochlear implantation in the Department of Otolaryngology, Kunming Children's Hospital from August 2016 to September 2021. Sanger sequencing of SLC26A4 gene was performed in 59 children with enlarged vestibular aqueduct. According to the genetic test results, the children who underwent temporal bone CT examination were divided into two groups: SLC26A4 biallelic mutation group（homozygous mutation and compound heterozygous mutation）, monoallelic mutation group, and the association with inner ear CT phenotype was analyzed, and the new sites were summarized and analyzed. Results:The c.919-2a>g mutation was the most common mutation in children with enlarged vestibular aqueduct with SLC26A4 gene mutation. Three new variants of SLC26A4 gene were found; CT examination combined with genetic testing found that a part of children with enlarged vestibular aqueduct was associated with SLC26A4 monoallelic mutation or no SLC26A4 gene mutation was detected. Further research is needed to investigate the involvement of other pathogenic factors in the pathogenesis of EVA.
Child ; Humans ; Mutation Rate ; Membrane Transport Proteins/genetics* ; China ; Hearing Loss, Sensorineural/diagnosis* ; Mutation ; Vestibular Aqueduct ; Vestibular Diseases/pathology* ; Deafness/genetics*

OBJECTIVETo study the clinical characteristics and diagnosis of the Johanson-Blizzard syndrome.

METHODThe clinical characteristics and diagnosing procedure of 1 case with Johanson-Blizzard syndrome were analyzed, and genetic analysis was made in diagnosing procedure, and 28 cases of Johanson-Blizzard syndrome with detailed clinical data were reviewed and analyzed.

RESULTA one year and nine months old girl, who was initially admitted to the hospital because of fatty diarrhea and increased frequency of defecation. Imperforate anus, and aplastic alae nasi was noticed after birth. On physical examination, short stature, mental retardation, tooth abnormalities and scalp defects were observed. Fat globule was found by routine stool test. Serum biochemistry showed an exocrine and endocrine pancreatic insufficiency, CT scan of the abdomen demonstrated fatty replacement of the pancreas, UBR1 gene analysis showed heterozygous for two missense changes. In all 29 cases, exocrine pancreatic insufficiency (72.4%) and hypoplasia of the alae nasi (93%) were the most common clinical manifestations, and sensorineural hearing loss (59%), scalp defects (69%) and hair thinning or upsweep of the hair (44.8%), hypothyroidism (44.8%), absence of permanent teeth (44.8%) and imperforate anus (21%) were also very common, but did not include consanguineous marriage of parents (10.3%).

CONCLUSIONJohanson-Blizzard syndrome is a rare autosomal recessive multisystem disorder, it is characterized by the association of congenital exocrine pancreatic insufficiency and hypoplasia or aplasia of the nasal wings, and can be diagnosed by clinical characteristics and UBR1 gene analysis.

Anus, Imperforate ; Deafness ; diagnosis ; genetics ; pathology ; Ectodermal Dysplasia ; diagnosis ; genetics ; pathology ; Female ; Growth Disorders ; Hearing Loss, Sensorineural ; Humans ; Hypothyroidism ; diagnosis ; genetics ; pathology ; Infant ; Intellectual Disability ; Nose ; abnormalities ; pathology ; Pancreatic Diseases ; diagnosis ; genetics ; pathology ; Ubiquitin-Protein Ligases ; genetics

OBJECTIVETo detect potential mutations of gap junction protein beta 2 (GJB2) and loricrin (LOR) genes in two patients with Vohwinkel syndrome.

METHODSPolymerase chain reaction and DNA sequencing were used for detecting potential mutations in the GJB2 and LOR genes. Parents of one patient and 50 healthy individuals were used as controls.

RESULTSA novel homozygous missense mutation (c.A796G) of LOR gene was detected in one patient. The same mutation was not found in the other patient, their relatives and the 50 healthy controls.

CONCLUSIONA missence mutation of LOR gene was detected in a patient with Vohwinkel syndrome.

Abnormalities, Multiple ; genetics ; pathology ; Adult ; Child, Preschool ; Connexin 26 ; Connexins ; genetics ; Female ; Hand Deformities, Congenital ; genetics ; pathology ; Hearing Loss, Sensorineural ; genetics ; pathology ; Humans ; Keratoderma, Palmoplantar ; genetics ; pathology ; Male ; Membrane Proteins ; genetics ; Mutation, Missense ; Sequence Analysis, DNA

Hypoparathyroidism, deafness, and renal dysplasia (HDR) syndrome is a rare condition inherited as autosomal dominant trait and characterized by hypoparathyroidism, sensorineural deafness, and renal dysplasia. HDR syndrome is caused by haploinsufficiency of the GATA3 gene located on chromosome 10p15. Here, we report the case of a 32-day-old Korean male with HDR syndrome. He was presented due to repeated seizures over previous 3 days. The patient was born after 40 weeks of gestation with birth weight of 2930 g, and was the first-born baby of healthy Korean parents. Hypoparathyroidism was first noticed due to seizure. A multicystic left dysplastic kidney and vesicoureteral reflux were detected by ultrasound after birth. Auditory brainstem response (ABR) testing revealed that the patient had moderate sensorineural deafness, with hearing losses of 80 dB at the mid and higher frequencies for both ears. Echocardiography finding revealed secundum atrial septal deftect. Based on biochemical results and clinical findings, a presumptive diagnosis of HDR syndrome was made. GATA3 mutation analysis identified a heterozygous deletion, c.153del (p.Phe51Leufs*144) in exon 1 causing a frameshift mutation, which is a novel de novo mutation. Therefore, we suggest that HDR syndrome should be considered in the differential diagnosis in symptomatic or asymptomatic patients with hypoparathyroidism, and that renal ultrasound or ABR testing be performed to prevent a missed diagnosis. This is the first report on Korean patient with confirmed HDR syndrome with novel mutation.
Base Sequence ; DNA Mutational Analysis ; GATA3 Transcription Factor/genetics ; Hearing Loss, Sensorineural/*genetics/*pathology ; Heterozygote ; Humans ; Hypoparathyroidism/*genetics/*pathology ; Infant, Newborn ; Kidney/abnormalities/ultrasonography ; Male ; Molecular Sequence Data ; Nephrosis/*genetics/*pathology ; Reproducibility of Results ; Republic of Korea ; Sequence Deletion

OBJECTIVETo investigate the whole sequence of the SLC26A4 gene in moderate to profound sensorineural hearing loss (SNHL) patients with IVS7-2A to G mutation of the gene in China.

METHODSWhole SLC26A4 gene sequence was analyzed by direct sequencing in 80 SLC26A4 gene IVS7-2A to G mutation carriers for the occurrence of a second mutation in the gene.

RESULTSForty-seven out of the 80 patients were found to have a second heterozygous mutation, whereas a single IVS7-2A to G mutation could be responsible for SNHL in the remaining 33 patients. Three novel mutations, 5+ 2T to A, 14-2A to G and 1825del G, were identified. The five most common mutations include H723R (20%), T410M(5%), C.1705+ 5G to A (15+ 5G to A)(5%), L676Q(5%), and N392Y (3.75%). Exon 17 harbored the most types of compound heterozygosity with the IVS7-2A to G mutation.

CONCLUSIONA Chinese specific SLC26A4 diversity was found, and comparable SLC26A4 contributing to deafness. This study suggested that if a heterozygous SLC26A4 mutation is found in a patient with deafness, other exons of the SLC26A4 gene should be analyzed. Furthermore, double heterozygosity of the SLC26A4 gene may also account for some of the disease phenotype.

Adolescent ; Amino Acid Sequence ; Animals ; Base Sequence ; Child ; Child, Preschool ; DNA Mutational Analysis ; methods ; Female ; Hearing Loss, Sensorineural ; genetics ; pathology ; Humans ; Male ; Membrane Transport Proteins ; chemistry ; genetics ; Mice ; Molecular Sequence Data ; Polymorphism, Single Nucleotide ; genetics ; Rats ; Young Adult

Stickler syndrome is a genetically heterogeneous disorder that affects the ocular, auditory, and musculoskeletal systems. Ocular-only variant of Stickler syndrome type 1 (OSTL1) is characterized by high risk of retinal detachment without systemic involvement and is caused by alternatively spliced exon 2 mutation of COL2A1. We report the cases of two Korean families with OSTL1 carrying likely pathogenic variants of COL2A1. All patients presented with membranous vitreous anomaly, peripheral retinal degeneration, and/or rhegmatogenous retinal detachment, but no systemic manifestations. By genetic analysis, two likely pathogenic non-exon 2 variants, c.2678dupC (p.Ala895Serfs*49) and c.3327+ 1G>C, were identified in COL2A1. Our results demonstrate that COL2A1 defects in OSTL1 are not confined to mutations in exon 2. Together with molecular data, ophthalmologists should consider genetic diagnosis of Stickler syndrome in patients with vitreous anomaly to prevent blindness from retinal detachment. To our knowledge, this is the first report of genetically confirmed OSTL1 in Korea.
Adult ; Arthritis/*genetics/pathology ; Asian Continental Ancestry Group/*genetics ; Base Sequence ; Collagen Type II/*genetics ; Connective Tissue Diseases/*genetics/pathology ; DNA Mutational Analysis ; Exons ; Female ; Hearing Loss, Sensorineural/*genetics/pathology ; Humans ; Male ; Middle Aged ; Republic of Korea ; Retinal Detachment/*genetics/pathology ; Visual Acuity