Embryos screened for deafness - a quiet first for Australia

From: Sydney Morning Herald, Australia - Jul 11, 2003

By Tom Noble

A woman who, with her partner, carries a genetic cause for deafness, failed to become pregnant after her IVF embryos were screened to guarantee a child with perfect hearing.

The couple want to remain anonymous as screening for deafness is at the heart of the medical ethics debate.

They produced seven embryos during the woman's IVF cycle. Each embryo was tested: one had two affected genes (so would become deaf), five carried one gene and one was all clear. The unaffected embryo was transferred into the Melbourne woman but no pregnancy occurred. The other carrier embryos were frozen and later transferred without success.

It is not known if the couple plan another IVF cycle.

The screening for mutations in the connexin 26 gene is the world's first reported case of an embryonic deafness test, according to details unveiled at the International Genetics Congress in Melbourne yesterday.

Non-syndromic deafness affects about one in 1000 children in the caucasian population. The couple each had one affected gene, but because the condition is recessive, neither was deaf. However, if they had a child, it had a one in four chance of inheriting the affected gene from both parents and being deaf.

The screening was authorised in September by Victoria's Infertility Treatment Authority, which regulates the type of tests that can be made on days-old embryos before they are implanted into the mother.

It said it regarded deafness as a medical condition, not a frivolous or cosmetic use of the technology.

However, the green light to screen out embryos carrying two deafness genes was attacked by ethicists who said it cleared the way to begin screening out other unwanted characteristics.

The British Deaf Association said it opposed genetic screening both on an established foetus or on eight-cell embryos produced through IVF.

More than 100 genetically-screened babies have been born in Australia since testing began about five years ago and screening has boomed in the past two years as genetic causes for a range of conditions have been identified.

Copyright  Â© 2003. The Sydney Morning Herald.