A marked fall in the number of babies born with inherited illnesses is possible, as a pre-pregnancy DNA test is used more widely.
The test checks whether prospective parents carry genes that, if both pass a copy to their child, will cause disease, known as a recessive condition. The test is usually only offered to people who know that recessive disorders such as cystic fibrosis run in their family.
But most carriers of these genes don鈥檛 have any such warning, says Alison Archibald at Victorian Clinical Genetics Services in Australia. In 2019, the country will start a trial, offering free tests to 10,000 couples regardless of family history, screening for 500 illnesses. If it leads to fewer babies born with these diseases, it may be offered nationwide.
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Since 2017, the American College of Obstetricians and Gynecologists has also recommended that all couples planning families have carrier tests for two of the most common recessive conditions: cystic fibrosis and spinal muscular atrophy.
鈥淪creening on a national scale could see rates of cystic fibrosis and spinal muscular atrophy fall sharply鈥�
In a study of 12,000 people in Australia, Archibald鈥檚 team found that one in 20 people carried genes for cystic fibrosis or spinal muscular atrophy. Of these, one in 40 had a partner who was also a carrier, giving them a one in four chance of having an affected child.
Screening on a national scale could see rates of genetic conditions fall sharply. Couples who test positive may choose to undergo IVF, allowing them to select embryos that are free of the condition.
Couples are also increasingly opting for early fetal screening in pregnancy. Since 2011, an early-pregnancy blood test for Down鈥檚 syndrome and other chromosomal disorders has been done by an estimated 10 million women worldwide.
There are concerns that more screening before birth will lead to discrimination against people with genetic conditions. But a study in Belgium found that 83 per cent of people with cystic fibrosis were in favour of pre-pregnancy screening.
This article appeared in print under the headline 鈥淣ews Preview 2019: Genetic disorders prevented鈥�
