Reproductive genetic carrier screening for cystic fibrosis, fragile X syndrome, and spinal muscular atrophy in Australia: outcomes of 12,000 tests

Genet Med. 2018 Apr;20(5):513-523. doi: 10.1038/gim.2017.134. Epub 2017 Oct 26.

Abstract

PurposeTo describe our experience of offering simultaneous genetic carrier screening for cystic fibrosis (CF), fragile X syndrome (FXS), and spinal muscular atrophy (SMA).MethodsCarrier screening is offered through general practice, obstetrics, fertility, and genetics settings before or in early pregnancy. Carriers are offered genetic counseling with prenatal/preimplantation genetic diagnosis available to those at increased risk.ResultsScreening of 12,000 individuals revealed 610 carriers (5.08%; 1 in 20): 342 CF, 35 FXS, 241 SMA (8 carriers of 2 conditions), approximately 88% of whom had no family history. At least 94% of CF and SMA carriers' partners were tested. Fifty couples (0.42%; 1 in 240) were at increased risk of having a child with one of the conditions (14 CF, 35 FXS, and 1 SMA) with 32 pregnant at the time of testing. Of these, 26 opted for prenatal diagnosis revealing 7 pregnancies affected (4 CF, 2 FXS, 1 SMA).ConclusionThe combined affected pregnancy rate is comparable to the population risk for Down syndrome, emphasizing the need to routinely offer carrier screening. The availability of appropriate genetic counseling support and a collaborative approach between laboratory teams, genetics services, health professionals offering screening, and support organizations is essential.

MeSH terms

  • Adult
  • Australia / epidemiology
  • Cystic Fibrosis / diagnosis
  • Cystic Fibrosis / epidemiology*
  • Cystic Fibrosis / genetics*
  • Female
  • Fragile X Syndrome / diagnosis
  • Fragile X Syndrome / epidemiology*
  • Fragile X Syndrome / genetics*
  • Gene Frequency
  • Genetic Carrier Screening* / methods
  • Genetic Testing
  • Humans
  • Male
  • Mass Screening
  • Middle Aged
  • Muscular Atrophy, Spinal / diagnosis
  • Muscular Atrophy, Spinal / epidemiology*
  • Muscular Atrophy, Spinal / genetics*
  • Pregnancy
  • Prenatal Diagnosis
  • Prevalence
  • Young Adult