Genetic testing provides hope for couple with family history of hearing loss

Vinay and Saroja (name changed), hailing from Vijayawada, Andhra Pradesh were a happy family until they discovered that their first born suffered from hearing and speech loss. They consulted various ENT specialists and as per their recommendation underwent a cochlear surgery for their son, whose hearing has been restored now. The couple experienced a lot of emotional trauma and were worried for their next unborn child.
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Vinay and Saroja opted for genetic counselling to understand if their second child will have the same issues as their first child and wanted to ensure their second child is normal. They consulted Dr. Sunitha Tella, Head of the Clinical Genetics and Fetal Medicine Department, at the Institute of Genetics and Hospital for Genetic Diseases, Hyderabad. She suggested the family to undergo genetic testing at MedGenome Labs, Bangalore, for the affected child. The first child, on being tested, was found to have two mutations (variants) in the GJB2 gene, which is associated with hearing loss. The parents were found to be carrying one mutation each, making them “carriers” for the disorder.

Carriers are those individuals who carry one defective copy of a gene (due to a mutation) but aren’t affected with the disease. However, these carriers are at a high risk of having a child who is affected, especially when they are married to another carrier for the same gene. This was the case in their first child, who inherited two defective copies of the GJB2 Gene, one from each parent. The risk of having a similarly affected child in each pregnancy is 25%.

Based on these findings, doing genetic testing for these two mutations in the next child was essential. During Saroja’s next pregnancy, the fetus was tested for these two variants. Fortunately, it was found that the fetus was only harboring one of the two mutations found in the first child. This meant that the child would be a carrier of the disease and wouldn’t suffer from hearing loss.

This gave a huge relief to Vinay and Saroja who were anxious until now regarding the health of their unborn child with respect to hearing loss. Genetic testing helped the couple to know that that their unborn child was not affected but just a carrier like them. Thus, genetic testing gave them hope and also allayed their anxiety.

This case also highlights the benefits for couples to undergo pre-conception counselling (i.e before planning for the next pregnancy) with a Genetic Counsellor; especially when there is positive family history for a disorder. Such counselling sessions help the couple better understand the risk to the child as well as help recommend a suitable Prenatal Genetic test.
Summary
  • The first child, on being tested, was found to have two mutations (variants) in the GJB2 gene, which is associated with hearing loss.
  • The parents were found to be carrying one mutation each. The risk of having a similarly affected child in each pregnancy is 25%.
  • During Saroja’s next pregnancy, the fetus was tested for these two variants. It was found that the fetus was only harbouring one of the two mutations found in the first child.
About MedGenome
MedGenome is the leading solution provider of clinical genomics for Physicians and Healthcare providers across India and offers unmatched expertise in clinical diagnosis, carrier testing, genetic counseling and validation of inheritance pattern. Our research solutions apply cutting-edge genomics technologies, bioinformatics, computing, and big data analytics to understand the genetic basis of various disorders.
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