Genomics in general practice


Neurological conditions
☰ Table of contents


Practice point


A small number of adult-onset neurological conditions are due primarily to a single gene mutation (eg Huntington’s disease). There are some more common neurological and neuromuscular conditions that have subsets due to specific gene variants (eg early-onset Alzheimer’s disease and early-onset Parkinson’s disease).1

Positive family history is important in diagnosing neurological conditions with a genetic cause (neurogenetic conditions).2

Relevant history includes:

  • two or more family members affected with the same condition
  • a significantly earlier age of onset than average (ie <50 years old for Parkinson’s disease and <65 years old for Alzheimer’s disease).



What do I need to know?


There are some neurological conditions that are caused by single gene variants that affect the normal function of muscles and the nervous system (eg neuropathies, myopathies, ataxias). There are also a large number of complex neurological conditions caused by an interplay of genetic and environmental factors.1,3

Genetic studies continue to identify variants that contribute to complex neurological conditions; however, there is currently no role for general practitioners (GPs) in ordering genetic testing for these conditions.

 


Genetic testing


Genetic testing (diagnostic testing and predictive testing) is available through specialist services4 for the following conditions:

  • Creutzfeldt–Jakob disease and other prion diseases
  • early onset Parkinson’s disease
  • familial epilepsy
  • familial motor neurone disease
  • Friedreich ataxia
  • hereditary peripheral neuropathies (Charcot–Marie–Tooth disease)
  • hereditary spastic paraparesis
  • Huntington’s disease
  • mitochondrial disorders
  • muscular dystrophies
  • myotonic dystrophy
  • spinal muscular atrophy
  • spinocerebellar ataxias.
 


When should I refer?


Individuals with suspected neurological conditions should be referred to a neurologist for clinical diagnosis, which may include genetic testing.
Referral to genetics services for predictive genetic testing of asymptomatic family members is appropriate in cases where:

  • there is a proven (clinically or by genetic testing) family history of an inherited neurological or neuromuscular condition
  • there is a suggestive family history as indicated by the presence of
    • two or more family members affected with the same condition
    • a significantly earlier age of onset than average.
 


Resource for patients


Evans-Galea M, Delatycki M, Lockhart P. Explainer: What are neurogenetic diseases? Melbourne: The Conversation, 2014


Genomics in general practice




 

 

  1. Biskup S, Gasser T. Genetic testing in neurological diseases. J Neurol 2012;259(6):1249–54.
  2. Bird TD. Approaches to the patient with neurogenetic disease. Clin Lab Med 2010;30(4):785–93.
  3. Toft M. Advances in genetic diagnosis of neurological disorders. Acta Neurol Scand Suppl 2014(198):20–25.
  4. The Royal College of Pathologists Australia (RCPA). Genetic tests and laboratories. [Accessed 22 January 2018].

Download

Genomics in general practice (PDF 3.1 MB)