Genomics in general practice

Personal genomic testing: Summary

Genomics in general practice
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  1. Summary of genetic testing
  3. Figures and tables
  4. Provided under licence

Last revised: 30 Nov 2018

Practice point

At this time, the clinical utility of personal genomic testing (PGT) is considered variable.1

If patients wish to pursue testing, ensure they opt for a full-service provider that includes the need for referral by a general practitioner (GP), test interpretation and genetic counselling support.
 

PGT refers to the analysis of some or all of a person’s genome. PGT is marketed for a variety of purposes, including:

  • identification of susceptibility to a wide range of diseases
  • carrier screening for autosomal recessive conditions
  • pharmacogenomics
  • nutrigenomics (ie diet, nutrition, wellness)
  • fitness and sporting abilities
  • ancestry
  • relationship (eg paternity) testing.

PGT companies may or may not require a health professional to order the test. In situations where a referral is not required, individuals can request a test kit online and provide a saliva or cheek swab sample to the PGT company via post. This is referred to as ‘direct-to-consumer’ (DTC) or ‘at-home’ genetic testing.

PGT companies are mostly based overseas, but an increasing number are now based in Australia.

The cost of PGT varies according to the type of test (eg genotyping, exome sequencing, whole genome sequencing) and how much information is provided with the results. PGT is not available under the Medicare Benefits Schedule (MBS), so consumers incur the full cost (sometimes thousands of dollars).

PGT results may be provided with some clinical interpretation in the form of follow-up genetic counselling or a written report, or as raw sequence data. In many situations, the consumer is left to interpret the results without clinical guidance. This can prompt the individual to contact their GP for additional support. Referral of all such patients to public genetics services for assistance is not practicable given the resource implications.1–3

Advising patients who want PGT

Patients may ask a GP to order PGT on their behalf. GPs asked to arrange PGT should consider the following:2,4

  • How much does the patient understand about the test?
  • What do they want to find out from the test and what will they do with that information?
  • Has the patient thought about the possible impact of testing on life insurance? (Refer to ‘Ethical principles’)
  • Will the company help interpret the results?
  • Do you feel able to assist the patient in interpreting results?

Managing patients who have had PGT

Patients who have already had PGT might ask a GP for:

  • help in interpreting the results
  • further testing
  • advice around treatment or management.

The majority of patients will have small variations in risks for a range of conditions, which will have limited clinical implications (eg Alzheimer’s disease, MTHFR gene testing). In these circumstances, general preventive health advice is appropriate.

In a minority of patients, specific variants that put an individual at significantly increased risk of a condition (eg BRCA gene mutations, HFE-haemochromatosis, macular degeneration) will be identified. In these situations, referral to genetics or specialist services is appropriate.4

Refer to ‘Personal genomic testing: More information’ for a detailed discussion of this topic.

National Health and Medical Research Council, Direct-to-consumer (DTC) genetic testing: A statement from the National Health and Medical Research Council

  1. Adams SD, Evans JP, Aylsworth AS. Direct-to-consumer genomic testing offers little clinical utility but appears to cause minimal harm. NC Med J 2013;74(6):494–98.
  2. Edelman E, Eng C. A practical guide to interpretation and clinical application of personal genomic screening. BMJ 2009;339:b4253.
  3. Trent R. Direct-to-consumer DNA testing and the GP. Aust Fam Physician 2014;43(7):436–39 [Accessed 8 January 2018].
  4. Capriotti T, Kline M. What to know about home genetic-test kits. New York: Clinical Advisor, 2014 [Accessed 8 January 2018].
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