Prenatal and preimplantation genetic diagnosis for single gene disorders: A population-based study from 1977 to 2016.

OBJECTIVE: To examine the statewide utilisation of prenatal diagnosis (PNDx) and preimplantation genetic diagnosis (PGT-M) for single gene disorders.

METHODS: Population-based study of all women utilising PNDx in the Australian state of Victoria from 1977 to 2016. Single gene disorders were categorised using a systematic approach that aimed to reflect aspects of the PNDx decision-making process. Data on PGT-M for single gene disorders from 2005 to 2016 were similarly examined for comparison. Statistical significance testing was performed with χ2 test.

RESULTS: Following an initial uptake period, annual PNDx rates for single gene disorders stabilised between 1.3 and 2.2 per 1000 births after the year 2000. The majority of PNDx (72%) was performed for disorders that primarily impair physical ability, while PNDx for adult onset conditions was rare (3%). PGT-M for single gene disorders has seen rapid growth since its introduction, and annual numbers now equal that of PNDx. In contrast to PNDx, one quarter of PGT-M tests were performed for adult onset conditions.

CONCLUSIONS: Our population-wide analysis has demonstrated a steady demand for PNDx for single gene disorders over the past decade, in contrast to the rapidly increasing utilisation of PGT-M. PGT-M appears to be the preferred testing modality for adult onset disorders.