You are here:

Genetics/Eye and Ear Defects.

Advertisement


Question
QUESTION: Dear Dr Natarajan

1. Is it possible that there could be Eye Birth defect in a child
where the child can have vision of only one eye ?. i.e. Child born with vision of only one eye. He/she cannot see with the other eye.

2.Is it possible that there could be Ear Birth defect in a child
where the child can hear with only one ear ?. i.e. Child born with able only to hear with only one ear. He/she cannot hear with the other ear.

Also it is possible that an adult can hear only with one ear i.e. Adult who was able to hear with both ears at birth is able to hear with only one ear. i.e. Has become Deaf with only one ear. Able to Hear with other ear. This may had happened due to ear related infections, diseases etc ?.

3. Statistically this type of Child Birth Defects can be rare ?.

i.e. Could it be 1 out of 1000 in Child Birth where the vision/hearing problem occurs only in one eye/ear ?.


Awaiting your reply,

Thanks & Regards,
Prashant S Akerkar

ANSWER: Hi Prashant,

As you question is not directed at any specific eye or ear defect, I will assume that you mean any birth defect affecting the eye. That said, there are conditions where one or both eyes may be affected. For eg., Coloboma is such a condition. It happens when the developing eye of the fetus stops before it is completely formed. This leads to an incompletely formed iris and depending on the severity, it can affect vision is several ways or even make the child blind in that eye.

Similarly for the ear. There are conditions where just one ear is affected. Generally hearing loss is not common in birth. Hearing loss can also develop in children who had normal hearing as infants. The loss can happen in in one or both ears and may be mild, moderate, severe, or profound.  Sometimes hearing loss gets worse over time. Other times it stays stable and does not get worse. Hearing loss can be caused by several conditions including genetic cause, infection etc.
Hearing loss can also occur in adults for various reasons like damage to ear drum, infection, tumor or genetic cause.

The incidence of eye/ear defect on one eye or ear depends on what condition you are looking at. As each of these may have difference causes, there is no general or one answer. If caused by envt pollution then even a rare condition can be frequent in the affected population. Genetic defects depend on family history also. For eg., coloboma occurs 1 in 10,000 births.

If you want info on a specific condition you have to state it. Also incidences differ in different population or races.

Hope this answers your questions,

T


---------- FOLLOW-UP ----------

QUESTION: Dear Dr Natarajan

Thank you.

A Baby born with this defect i.e.

1. Able to have vision only with one eye (Left or right). Able to hear with both ears. - Partial Blindness
2. Able to hear only with one ear (Left or right). Able to see with both eyes. - Partial Deafness
3. Able to see and hear both with one eye and one ear. (i.e. Either with Right eye/Right ear OR Left eye/Left ear) - Partial Blindness + Partial Deafness.

Do you feel for the above Defect/Syndrome/Disorder, Can Vaccines be created
in future and can be given to a Pregnant woman so that this defect/s can be avoided after child birth ?.

Awaiting your reply,

Thanks & Regards,
Prashant S Akerkar

ANSWER: Hi Prashant,

The condition you describe can have genetic cause or genetic plus environmental cause.

If it is purely genetic and the causal gene is known, then at the most, genetic counseling is provided. Further, IVF can be done to select an embryo with normal genes. However, genetic disorders have no vaccine.
If the condition is caused by environmental pollution or infection in early stages of pregnancy, again, there is no such thing as a vaccine for the same.

Most of the time, such defects are caused by more than one gene or a one time insult during pregnancy that prevented the development of the ear or eye. These events cannot be predicted and are also difficult to prevent or treat unless cause is known clearly.

Genetic counseling and planning the next child with assisted birth can help to some extent when cause is known.

Best,

T


---------- FOLLOW-UP ----------

QUESTION: Dear Dr Natarajan

Thank you.

As you mention "If the condition is caused by environmental pollution or infection in early stages of pregnancy, again, there is no such thing as a vaccine for the same".

Regarding this possible reason/s mentioned for the eye/ear disorder caused, Do you feel with further extensive research it is possible to develop vaccines and can be given to a Pregnant woman in early stages
of Pregnancy (Specific week/s of Three Trimesters) to prevent this disorder
when the baby is born ?.


Awaiting your reply,

Thanks & Regards,
Prashant S Akerkar

Answer
Hi Prashant,

Vaccines can be developed if a gene mutation results in a protein that prevents the normal functioning. In most cases, the problem arises as a result of loss of gene function. In this case you would need to compensate for this loss - say- by gene therapy.

The factors that converge to result in such developmental defects as I mentioned before, are usually  very complex and multi-factorial. So which factor will you prevent? or if several genes are playing a role, which gene will you address. And finally, vaccines etc that can cross the blood-fetal barrier, can often cause more harm than good. You have to really monitor the spatial and temporal  aspect. Sometimes there is only a small window of time- say a few hours when a remedy may have to be administered and this window may be something like 93rd day since the time of conception.  It is due to the extremely complex and delicate process that to date there is no vaccine to prevent a birth defect. Though there are vaccines to prevent infection during pregnancy and sometimes this can also result in spontaneous miscarriage or even other birth defects.

So, my take is that, extensive research can help find a cause and therefore prevent it by modifying lifestyle or avoiding the causing agent, rather than by administering vaccine.

Best,

T

Genetics

All Answers


Answers by Expert:


Ask Experts

Volunteer


Thanemozhi Natarajan

Expertise

Answers in Genetics, genomics, cytogenetics of syndromes, congenital anomalies, cancer, clinical genomics and interpretation of omics data.

Experience

More than 10 years. Doctoral research thesis on Congenital anomalies and cytogenetics, Recurrent reproductive failure and chromosomal abnormalities. Postdoctoral experience in Breast cancer research. Current: Clinical Genomics and Pharmacogenomics.

Organizations
Academic

Publications
Cancer Cell International, Cancer Epidemiology Biomarkers and Prevention, Breast cancer research and treatment, Indian Journal of Pediatrics, BMC Proceedings, Pharmacogenetics and Genomics, Human Molecular Genetics, Frontiers in Genetics, Cancer Biomarkers.

Education/Credentials
PhD Biomedical Genetics

Awards and Honors
University Grants Commission Award for pursuing PhD level research (India); Travel awards to attend conferences.

Past/Present Clients
Post doctoral experience Cancer research, molecular epidemiology Current: Clininical Genomics and Pharmacogenomics

©2016 About.com. All rights reserved.