Many genetic diseases are known to be caused by changes or variants in a single gene. These are known as single gene disorders. An example of a single gene disorder is cystic fibrosis, which is caused by variants in the CFTR gene. The type of test method required for each disorder will depend on the type of gene change that causes that disorder.
VCGS provides a comprehensive range of diagnostic tests for a broad range of childhood and adult single gene disorders.
Single gene testing is performed to identify changes or variants in a single gene. The type of testing and who will require testing will depend on the inheritance pattern and type of variant being investigated. Single gene disorders are often called Mendelian disorders and are divided into categories depending on how they are inherited. The most common inheritance patterns are dominant, recessive and X-linked.
VCGS offers a broad range of testing across childhood and adult referrals. These include ataxias, dystrophinopathies, cystic fibrosis, fragile X syndrome and many development syndromes. Please see below for our full list of single gene tests.
Testing for single gene disorders is performed where a patient has presented with specific features of a condition or when there is a family history of the condition. Testing is typically arranged by a specialist like a paediatrician or neurologist. In some cases, a referral to see a genetic counsellor may be arranged prior to testing.
What are the different inheritance patterns for single gene disorders?
In most circumstances, we have two copies of every gene: one inherited from each of our biological parents.
Dominant disorders are caused when there is a variant in only one of the two gene copies.
Recessive disorders only occur when both copies of a gene carry a variant and in these circumstances both parents are usually asymptomatic carriers of a variant in one of their genes.
X-linked disorders are caused by variants in genes located on the X chromosome. Because males only have a single X chromosome, they are usually more severely affected than females who have two X chromosomes.
How much does testing cost?
Please see test and specimen requirements for each test for pricing.