Expanded carrier screening for 224 monogenic disease genes in 1,499 Chinese couples: a single-center study

Abstract Objectives Expanded carrier screening (ECS) is a preventive genetic test that enables couples to know their risk of having a child affected by certain monogenetic diseases. This study aimed to evaluate the carrier frequency for rare monogenic diseases in the general Chinese population and the impacts of ECS on their reproductive decisions and pregnancy outcomes. Methods This single-center study was conducted between September 2022 and April 2023. An ECS panel containing 224 recessive genes was offered to 1,499 Chinese couples from the general population who were at early gestational ages or planned to conceive. Results Overall, 55.0 % of the individuals carried for at least one recessive condition. There were 16 autosomal recessive (AR) genes with a carrier frequency of ≥1/100 and 22 AR genes with a carrier frequency of <1/100 to ≥1/200. The most common AR and X-linked diseases were GJB2 -related non-syndromic hearing loss, and hemolytic anemia, respectively. Fifty-five couples (3.67 %; 1 in 27.3) were at increased risk of having an affected child with 19 pregnant at the time of testing. Of these, 10 opted for amniocentesis, and four affected pregnancies were identified, with three of them being terminated. Conclusions This study not only provides valuable information about the recessive genetic landscape, but also establishes a solid foundation for couple-based ECS in a real clinical setting.