The technology for safe, cheap screening for the principal gene mutations responsible for cystic fibrosis has long been available. Nearly 10 years ago, the US National Institutes of Health recommended “testing for gene mutations that cause [cystic fibrosis] be offered as an option to all pregnant couples and those planning a pregnancy”.1 A similar recommendation has been made by a joint committee of the American College of Obstetricians and Gynaecologists and the American College of Medical Genetics.2 In 1998, this Journal published an editorial emphasising the need for Australia to follow suit in promoting carrier screening for cystic fibrosis.3 There has been little response despite the fact that each year 70 babies are born in Australia with cystic fibrosis, almost all to parents with no family history.4

Cystic fibrosis is the most common severe autosomal recessive disease of childhood, with an incidence of 1 in 2500 and carrier frequency of 1 in 25. Clinical manifestations include progressive, irreversible suppurative lung disease and pancreatic exocrine insufficiency. Although most children with cystic fibrosis can expect to survive into adulthood, the daily therapies are rigorous, and there are many years of ill health. The median life expectancy is in the mid-30s, with end-stage lung disease the major cause of death. There is still no cure.

Most patients with cystic fibrosis are detected by newborn screening, using a biochemical test (for immunoreactive trypsinogen [IRT]) for all babies, followed by cystic fibrosis gene mutation analysis for those with a raised IRT level. Newborn screening facilitates the early diagnosis of cystic fibrosis and genetic counselling for affected families. Couples identified with an affected infant can choose prenatal testing using gene mutation analysis from a chorionic villus sample for subsequent pregnancies to ascertain the status of the fetus.

The genetic test used for diagnosis of cystic fibrosis and prenatal testing can also be used to identify carriers of a cystic fibrosis gene mutation. Testing for cystic fibrosis gene mutations is reliable, and, with a 12-mutation panel, nearly 85% of possible severe mutations can be detected. It can be performed using a painless cheek swab. However, testing for carrier status is generally not offered in Australia to couples without a family history, and most of those who carry a mutation do not know until an affected child is born. While we acknowledge the benefits of newborn screening, we believe it would be better to offer cystic fibrosis gene mutation screening to all couples, before they had their first baby with cystic fibrosis.

Prenatal screening for a variety of conditions is routine in Australia. All women have a full blood count early in pregnancy, and those who are iron replete with a low mean cell volume are tested for thalassaemia carrier status. The outcome is that it is now uncommon for babies to be born with thalassaemia. Prenatal screening for Down syndrome (using a combination of ultrasound examination and measurement of serum markers) has been offered since 1996, and more than two-thirds of pregnant women in Victoria participate in this screening. Populations with a high frequency of genetic conditions such as Tay–Sachs disease are also offered prenatal or preconceptual screening. Paradoxically, the carrier frequency of cystic fibrosis in the general Australian population is almost the same as the carrier frequency of Tay–Sachs disease in the Ashkenazi Jewish population.5 Lack of awareness about cystic fibrosis no doubt contributes to the lack of community pressure to screen.

A successful prenatal screening program for cystic fibrosis has been pursued in Edinburgh for many years.6 This program uses a model of couple testing for carrier status with the offer of prenatal genetic testing of the fetus when both partners are carriers and has halved the incidence of cystic fibrosis in that community.7 Uptake of the service is 80%,6 similar to the uptake in a smaller Dutch study.8 In Victoria, 67% of couples with an infant with cystic fibrosis have used prenatal testing for subsequent pregnancies.9 Some families have opted for pre-implantation genetic diagnosis (with in-vitro fertilisation technology) to avoid pregnancy termination.

We advocate a cystic fibrosis screening program in which both parents are encouraged to be screened at the same time, which will give the most accurate risk assessment of the couple having a baby with cystic fibrosis (Box). Ideally, screening would be performed before conception, to allow the couple time to decide on the best reproductive option. In reality, many women do not present for pre-pregnancy assessment, so a screening model that allows prenatal testing of the couple should remain available. Furthermore, we advocate that both parents receive their individual carrier result to maximise the opportunities for cascade family testing. Any program offering carrier screening needs to include genetic counselling for carrier couples, individual carriers and relatives of carriers who may also wish to be tested.

Extensive data clearly demonstrate the cost effectiveness of cystic fibrosis screening. The lifetime cost of care for a patient with the condition outweighs the cost of screening women of child-bearing age.10,11

Cystic fibrosis carrier screening should be a federal initiative. Currently, the care of patients with cystic fibrosis and the newborn screening programs are state funded, and there is little incentive for a national program. A Medicare-rebatable test would allow universal access and encourage uptake. Surely, it is time to fund carrier screening for cystic fibrosis in Australia.