Analysis of results of concurrent hearing and deafness genetic screening and follow up of 33 911 newborns / 中华医学遗传学杂志

OBJECTIVE@#To analyze the results of concurrent hearing and deafness genetic screening and follow up of newborns.@*METHODS@#In total 33 911 babies born to 5 designated hospitals in Nanshan District of Shenzhen city from October 2017 to December 2019 were included. All subjects underwent concurrent hearing and deafness genetic screening covering 21 variants of 4 genes including GJB2, SLC26A4, GJB3 and Mt12SrRNA. For those with positive results, Sanger sequencing was carried out for confirmation.@*RESULTS@#93.32% subjects passed the first-round hearing screening, and 87.01% passed the recheck testing. The overall detection rate was 4.18%. The detection rates for GJB2, SLC26A4, GJB3 and Mt12srRNA variants were 1.98%, 1.58%, 0.37% and 0.25%, respectively. 126 and 84 subjects were found with high risk for delayed-onset and drug-induced hearing loss, respectively. In addition, 4 and 5 subjects were found to harbor homozygous/compound heterozygous variants of the GJB2 and SLC26A4 genes, respectively. Concurrent screening showed that subjects (with heterozygous variants) who did not passed the two round hearing test were as follows: GJB2 with 6.75% in the first round and 2.61% in the second round testing, SLC26A4 (3.3%/1.2%), GJB3 (0.72%/0.14%) and 12SrRNA (0.36%/Nil), respectively. Moreover, the No-pass rate in the subjects with homozygous or compound variants in single gene, heterozygous variant in single gene, heterozygous variant in multiple genes, and homozygous variant in GJB3 gene were significantly higher than the subjects with negative results of genetic screening.@*CONCLUSION@#Concurrent newborn genetic screening can enhance the effectiveness of hearing screening and enable earlier identification and intervention for children with hearing impairment. Follow-up can improve the diagnostic rate for children who are positive for the concurrent screening. Nevertheless, genetic and hearing screening cannot replace the diagnostic testing. It is necessary to conduct comprehensive analysis for the results of genetic and hearing screening and radiological examinations. Sanger sequencing and next-generation sequencing are critical for ascertain the diagnosis.

Investigation of the A1555G mutation in mitochondrial DNA (MT-RNR1) in groups of Brazilian individuals with nonsyndromic deafness and normal-hearing.

BACKGROUND: Mutations of mitochondrial DNA were described into two genes: The mitochondrially encoded 12S RNA (MT-RNR1) and the mitochondrially encoded tRNA serineucn (MT-TS1). The A1555G mutation in MT-RNR1 gene is a frequent cause of deafness in different countries. AIM: The aim of this work was to investigate the frequency of the A1555G mutation in the MT-RNR1 gene in the mitochondrial DNA in Brazilians individuals with nonsyndromic deafness, and listeners. MATERIALS AND METHODS: DNA samples were submitted to polymerase chain reaction and to posterior digestion with the Hae III enzyme. RESULTS: Seventy eight (78) DNA samples of deaf individuals were analyzed; 75 showed normality in the region investigated, two samples (2.5%) showed the T1291C substitution, which is not related to the cause of deafness, and one sample (1.3%) showed the A1555G mutation. Among the 70 non-impaired individuals no A1555G mutation or T1291C substitution was found. CONCLUSION: We can affirm that A1555G mutation is not prevalent, or it must be very rare in normal-hearing subjects in the State of Paraná, the south region of Brazil. The A1555G mutation frequency (1.3%) found in individual with nonsyndromic deafness is similar to those found in other populations, with nonsyndromic deafness. Consequently, it should be examined in deafness diagnosis. The investigation of the A1555G mutation can contribute towards the determination of the nonsyndromic deafness etiology, hence, contributing to the correct genetic counseling process.

Origin, evolution and homologies of the Weberian apparatus: a new insight / Origen, evolución y homologías del aparato weberiano: un nuevo acercamiento

The Weberian apparatus is essentially a mechanical device improving audition, consisting of a double chain of ossicles joining the air bladder to the inner ear. Despite being one of the most notable complex systems of teleost fishes and the subject of several comparative, developmental and functional studies, there is still much controversy concerning the origin, evolution and homologies of the structures forming this apparatus. In this paper I provide a new insight on these topics, which takes into account the results of recent works on comparative anatomy, paleontology, and ontogeny as well as of a recent extensive phylogenetic analysis including not only numerous otophysan and non-otophysan extant otocephalans but also ostariophysan fossils such as Chanoides macropoma, Clupavus maroccanus, Santanichthys diasii, Lusitanichthys characiformis, Sorbininardus apuliensis and Tischlingerichthys viohli. According to the evidence now available, the Weberian apparatus of otophysans seems to be the outcome of a functional integration of features acquired in basal otocephalans and in basal ostariophysans, which were very likely not directly related with the functioning of this apparatus, and of features acquired in the nodes leading to the Otophysi and to the clade including the four extant otophysan orders, which could well have been the result of a selection directly related to the functioning of the apparatus.

El aparato weberiano es esencialmente un dispositivo mecánico que mejora la audición, consiste en una doble cadena de osículos que unen la cámara de aire al oído interno. A pesar de ser uno de los sistemas complejos más notables de peces teleósteos y objeto de varios estudios comparativos, de desarrollo y funcionales, todavía hay mucha controversia sobre el origen, evolución y homologías de las estructuras que forman este aparato. En este trabajo se proporciona una nueva visión sobre estos temas, que tiene en cuenta los resultados de los últimos trabajos sobre la anatomía comparada, paleontología y la ontogenia, así como de un reciente análisis filogenético amplio que incluyen no sólo numerosos otocéfalos Otofisios y no Otofisios existentes, sino también fósiles Ostariofisios como Chanoides macropoma, Clupavus maroccanus, Santanichthys diasii, Lusitanichthys characiformis, Sorbininardus apuliensis y Tischlingerichthys viohli. Según las pruebas disponibles, el aparato weberiano de Otofisios parece ser el resultado de una integración funcional de las características adquiridas en otocéfalos basales y en ostariofisios basales, los cuales muy probablemente no estén directamente relacionados en el funcionamiento de este aparato, y las características adquiridas en los nodos que condujeron a los Otofisios y al clade incluyendo las cuatro órdenes existentes otofisios, que bien podrían haber sido el resultado de una selección directamente relacionada con el funcionamiento del aparato.

Factores de alto riesgo en audición

Se investigó el nivel de audición en 50 lactantes de 3 a 12 meses de edad, nacidos en la Maternidad Isidro Ayora de la ciudad de Quito; y que tenían al nacimiento historia positiva para factor de riesgo en audición; mediante la realización de potenciales auditivos del tronco cerebral (ERA). Previamente mediante otoscopia microscópica e impedanciometria, se descartó ocupación de oido medio y la posibilidad de una hipoacusia conductiva adquirida. Los resultados mostraron que el 16 por ciento de estos niños eran poseedores de déficits auditivos. Este grupo fue comparado con otro, que incluyó a 50 lactantes de 3 a 12 meses de edad nacidos en la Maternidad Isidro Ayora, pero con historia negativa para factores de riesgo; utilizando las mismas técnicas de diagnostico que para el primer grupo; en estos niños no se pudo detectar pérdidas auditivas; en efecto el 100 por ciento de estos 50 infantes, fueron normales en lo que se refiere a su capacidad auditiva.