Genomics in general practice


Reproductive carrier screening
☰ Table of contents


Practice point


All women or couples planning a pregnancy, or who are already pregnant, should have a comprehensive family history recorded.1

Women or couples who are known carriers of a genetic condition or have a relevant family history should be made aware of the availability of carrier screening and offered referral to specialist services (ie genetics or obstetrics).1

Information on carrier screening for the more common genetic conditions that affect children (eg cystic fibrosis [CF], spinal muscular atrophy [SMA], fragile X syndrome [FXS]) should be offered to low-risk women and couples (ie regardless of family history and ethnicity).

The decision to have screening is a personal choice to be made by the individual or couple.

 


What do I need to know?


Reproductive carrier screening is used to identify carriers of genetic conditions with an Autosomal recessive inheritance or X-linked inheritance pattern.
Information about carrier screening can be offered to all women or couples during pre-conception and early in the pregnancy (ie first trimester). Identifying carrier couples before pregnancy provides greater reproductive options.

For example:

Traditionally, reproductive carrier screening for inherited recessive conditions was offered on the basis of ethnicity. However, this is known to lead to significant under-identification of carrier couples. Given the multicultural nature of society and marriage between people of different ethnic backgrounds, ethnicity is poorly predictive of carrier frequency in Australia.

The decision to undertake carrier screening is a personal choice to be made by the individual or couple. Women or couples should be informed of the benefits, limitations and cost of screening. Ideally, this information is provided pre-pregnancy.1

 

Genetic testing


A number of pathology services offer carrier screening, which can be ordered through general practice. However, carrier screening is not available through the Medicare Benefits Schedule (MBS). Depending on the test provider:

  • screening may look for a limited number of conditions (eg CF, Fragile X syndrome [FXS], spinal muscular atrophy) or screen for an expanded range of conditions (ie >100)
  • genetic counselling may or may not be available.

Note: Carriers of haemoglobinopathies may be initially identified through a routine full blood examination (FBE). Mackenzie’s Mission, a national research project funded by the Federal Government, will commence in late 2019. It aims to identify how reproductive carrier screening for an expanded range of conditions can best be made available to Australian couples who want it.

 

When should I refer?


Couples identified as carriers of a genetic condition should be offered referral to specialist services (ie genetics or obstetrics).

 

Other considerations


Carrier screening needs to occur in a timely manner to provide women or couples with reproductive options. The testing of biological male partners of pregnant female carriers is of particular importance.

 

Resources for general practitioners


Henneman L, Borry P, Chokoshvili D, et al. Responsible implementation of expanded carrier screening. Eur J Hum Genet 2016;24(6):e1–e12.
The Royal Australian College of General Practitioners, Guidelines for preventive activities in general practice

 

Resources for patients


Information

Cystic Fibrosis Community Care, Cystic fibrosis carrier screening

Support

Spinal Muscular Atrophy (SMA) Australia
The Fragile X Association of Australia


Genomics in general practice




 

 

  1. The Royal Australian and New Zealand College of Obstetricians and Gynaecologists. Prenatal screening and diagnostic testing for fetal chromosomal and genetic conditions (C-Obs 59). Melbourne: RANZCOG, 2018. [Accessed November 2018].

Download

Genomics in general practice (PDF 3.1 MB)