Gene Access (CF, SMA & FXS)

Gene Access

The Clinical Labs Gene Access Genetic Carrier Screening test provides patients with information regarding their chances of having a child with cystic fibrosis (CF), spinal muscular atrophy (SMA), or fragile X syndrome (FXS).

• One in 20 individuals are carriers of at least one of these conditions;
• 90% of carriers do not have a family history;
• One in 160 couples will be found to be at risk of having an affected child.
   

CYSTIC FIBROSIS (CF)

Approximately one in 25 individuals are carriers of CF, and CF genetic testing covers more than 75 common mutations in the CFTR gene. CF affects about 1 in 2,500 individuals and is a severe genetic condition that causes lung and gastrointestinal problems.

SPINAL MUSCULAR ATROPHY (SMA)

SMA is an inherited neuromuscular disease historically associated with high morbidity and mortality. Approximately one in 35 individuals are carriers of SMA, and the SMA test identifies deletions of the SMN1 gene. SMA affects about 1 in 6,000 people.

FRAGILE X SYNDROME (FXS)

FXS is the most common inherited form of intellectual disability, affecting approximately 1 in 3,600 men and 1 in 6,000 women. FXS carrier screening is recommended for females, as it is inherited in a different way to CF and SMA, and it only requires that the female has the gene change (number of repeats) in the FMR1 gene for there to be a risk of having a child affected by FXS.

Genetic Carrier Screening should be offered to every woman or couple

Australian clinical guidelines (RANZCOG & RACGP)^1,2 recommend offering genetic carrier screening for common genetic conditions, such as cystic fibrosis, spinal muscular atrophy, and fragile X syndrome, to every woman or couple who are either planning or in the first stage of pregnancy, regardless of their probability of having these conditions.

Ideally, screening is performed prior to conception to offer greater reproductive choice. Early detection is paramount as it allows more time for counselling and provides greater reproductive options for those at risk. With carrier screening for CF, SMA, and FXS being Medicare-rebatable, testing can be offered earlier during routine appointments, alongside other prenatal screening tests.

<sup>1. The Royal Australian and New Zealand College of Obstetricians and Gynaecologists (RANZCOG) Guidelines. 
2. The Royal Australian College of General Practitioners (RACGP) Guidelines.</sup>

Medicare Eligibility Criteria

New items 73451 and 73452 

The patient who is planning pregnancy or already pregnant should be tested first under MBS item 73451 prior to testing the reproductive partner patient under MBS item 73452 to ensure an informative and clinically relevant test result is obtained in the relevant gene.

73451 

Testing of a patient who is pregnant or planning pregnancy to identify carrier status for pathogenic or likely pathogenic variants in the following genes, for the purpose of determining reproductive risk of cystic fibrosis, spinal muscular atrophy, or fragile X syndrome: 

a.    CFTR; 
b.    SMN1; 
c.    FMR1.

One test per lifetime. 

73452

Testing of the reproductive partner of a patient who has been found to be a carrier of a pathogenic or likely pathogenic variant in the CFTR or SMN1 gene identified by testing under item 73451, for the purpose of determining the couple’s reproductive risk of cystic fibrosis or spinal muscular atrophy. 

One test per condition per lifetime. 

Reproductive carrier testing for cystic fibrosis, spinal muscular atrophy, and fragile X syndrome

MBS items 73451 and 73452 

The intent of MBS item 73451 is to test an asymptomatic female chromosomal sex patient who is either planning a pregnancy or is already pregnant. 

The intent of MBS item 73452 is to test an asymptomatic male chromosomal sex patient who is the reproductive partner of the patient planning pregnancy or already pregnant and has been tested under item 73451.