Genetic Carrier Screening

Why recommend screening to your patients?

Genetic carrier screening helps inform reproductive decision-making. For carrier couples (where both partners are carriers for autosomal recessive conditions like CF or SMA, or the female partner is a carrier for an X-linked condition like FXS), screening provides the opportunity to consider a range of reproductive options.

Due to the recessive nature of these conditions, 88% of carriers have no family history.¹

Expanded carrier screening plays a crucial role in identifying individuals or couples at increased risk of having children with a wider range of serious inherited genetic disorders. Screening panels vary in scope – from fewer than 10 genes to more than 500 – allowing you to tailor the offer to your patient's needs.

When to offer screening

RANZCOG recommends that information on carrier screening be offered to all women planning a pregnancy or in the first trimester of pregnancy.² This includes screening for CF, FXS and SMA. The genetic carrier screening test can be easily added as part of a patient's routine antenatal blood screening.

There is global consensus that genetic carrier screening is best performed before pregnancy. This gives your patients the widest range of reproductive choices and more time to make important decisions.

Carrier screening can still be offered in early pregnancy, although options will be more limited and time-sensitive.

Recommended screening pathway (standard panel): Test the female partner first, followed by the male partner if the female is identified as a carrier for CF or SMA.

For expanded screening, couples may choose to test together or sequentially based on your clinical guidance.

Screening options: Standard vs. Expanded

Accuracy of screening results (Standard Panel)

Our genetic carrier screening tests for the most common genetic changes associated with CF, SMA and FXS. The assay can detect:

• >99.9% of cystic fibrosis carriers
• >99% of fragile X carriers
• >95% of spinal muscular atrophy carriers

Key technical updates:

• Massively parallel sequencing (NGS) improves identification of CF carriers
• AGG interrupt analysis provides a more precise estimate of the chance of a premutation expanding to a full mutation in the next generation, helping to better inform reproductive choices for FXS carriers

The tests used are highly accurate diagnostic tests that reliably identify carriers for these conditions. However, genetic carrier screening cannot identify a small percentage of carriers because some very rare genetic variants cannot be detected by the test.

Why use the Natera Horizon Expanded Carrier Screen?

At Genomic Diagnostics, we've partnered with Natera to offer the Horizon expanded carrier screen. Key features include:

• Comprehensive joint reports for couples – offering clear reproductive risk assessments when one or both partners are carriers
• Free pre-test genetic information sessions for all patients, ensuring informed decision-making
• Free post-test genetic counselling for carrier couples, including specialised support for females with X-linked disorders
• Post-test information sessions at no cost for all other patients

This test is designed to provide unparalleled support for both you and your patients, ensuring a streamlined and informed process at every stage.

Reproductive options to discuss with carrier couples

When carrier status is identified, patients can consider:

• Natural pregnancy, with or without prenatal diagnosis
• Pre-implantation genetic diagnosis (PGD) with IVF to test and transfer embryos free of the condition
• Use of a sperm or egg donor
• Adoption