Objective: To investigate the applicability of carrier screening in women undergoing invasive prenatal diagnosis.
Design: Prospective study.
Setting: University-based clinic.
Participants: Two hundred and fifty-six pregnant women.
Methods: Gene tests were offered for fragile X syndrome, aspartylglycosaminuria and infantile neuronal ceroid lipofuscinosis at the time of invasive prenatal testing.
Results: The overall uptake of the tests was 92%. Previously unrecognised carriership was found in 10 women: aspartylglycosaminuria (7); infantile neuronal ceroid lipofuscinosis (2) and fragile X (1). Fetal genotyping was carried out in one carrier of aspartylglycosaminuria whose partner was also a carrier, and in one woman who was found to have fragile X premutation. Both fetuses were unaffected.
Conclusion: Carrier screening for single-gene disorders is feasible and well accepted among pregnant women undergoing invasive prenatal testing. The major benefit is that there is no need to consider extra invasive tests when carriership is detected. Incorporation of genetic testing into fetal karyotyping gives more security to future parents.