Preimplantation Genetic Diagnosis: Its Role in Prevention of Deafness

Abstract

Deafness is a global problem. In India deafness ranges from 4 % in urban to 11 % in rural and slum areas, out of which 50 % is conductive hearing loss hence curable. Genetic transmission accounts for 50 % of the cases of congenital deafness, and of these, around 30 % are syndromic and 70 % are non-syndromic. Genetic counseling is going to make aware the parents of all appropriate treatments. Preimplantation genetic diagnosis can help to have a baby free from genetic deafness. Procedure is almost safe, harmless, non-invasive and ethically acceptable. While Amniocentesis is a non-invasive method, prenatal genetic testing through Chorionic villous sampling is invasive. The connexin 26 (CX26W 24X) mutations are the most common cause of non-syndromic hearing loss and easy to identify by polymerase chain reaction. There is always co-morbidity after cochlear implantation and the person remains handicapped while baby after PGD shall be having healthy normal life and person prone to environmental factors may be counseled and guided to prevent deafness in next generation. Public must be made aware of noise pollution, tobacco toxicity and consanguinity. The Obstetrician and Pediatrician apart from ENT surgeon should be involved to prevent antenatal or neonatal deafness.Keywords Sensorineural deafness Á Preimplantation Á Genetic diagnosis Á National deafness programme Hearing loss is the most common sensory impairment known to man. On an average 6.3 % of the Indian population suffers from hearing loss which ranges from 4 % in urban to 11 % in rural and slum areas. For screening, preventing, counseling and curing deafness, it can be divided into two groups-conductive and sensorineural deafness. Conductive hearing loss is a mechanical defect in sound conduction from pinna through the external auditory canal, tympanic membrane, middle ear up to the annular ligament at stapedeal foot plate (Otosclerosis) [1].Sensorineural hearing loss is most commonly due to the involvement of sensory hair cells of the cochlea or sometimes of the auditory nerve or processing centre in the brain. About 50 % of the patients with sensorineural deafness are congenitally deaf. Genetic transmission accounts for 50 % of the cases of congenital (hereditary) deafness-most due to single gene mutations-and at least 90 % are inherited as Autosomal recessive traits. Of these, around 30 % are syndromic and 70 % are non-syndromic.

Deafness, a Social Stigma: Physician Perspective

“…Consanguinity may be an additional factor in certain communities which can be highlighted and avoided by visuals/publicity. In case of familial deafness option of preimplantation genetic diagnosis should be explained and Government should support to prevent/reduce incidence of deafness in India [10,11].…”

Successful preimplantation genetic diagnosis by targeted next-generation sequencing on an ion torrent personal genome machine platform

“…The primary cause of hearing loss is attributed to genetic or environmental factors ( 3 ). Genetic transmission accounts for 50% of cases of congenital deafness, and of these, ~30% are syndromic and 70% are non-syndromic ( 4 ). Syndromic hearing loss (SHL) or non-(N) SHL refers to hearing loss with or without clinical symptoms, respectively ( 5 ).…”

Preimplantation Genetic Diagnosis in India: The Current Scenario and Potential Developments

“…A recent study undertaken in the UK cleared the implication that PGD increased the frequency of pre-term birth and low birth weight using data collected from the Human Fertilisation and Embryology Authority (HFEA), UK regarding singleton birth after in vitro fertilisation (IVF) and/or intracytoplasmic sperm injection (ICSI) treatment during 1996-2011 [3][4][5].…”