Information about genetics
Tourette’s is an inherited neurological disorder that causes verbal
and motor tics.
It is estimated that ~0.3% to 0.8% of the world’s population has
As with many other neurological disorders, males have Tourette’s
more frequently than females. It is suggested that this is because
females have a larger basal ganglia.
Twin studies show that although Tourette’s is an inherited disorder,
there is a lot of variability in its expression based on environmental
Studies suggest that mutations in many different genes combine to
cause Tourette’s Syndrome. This makes it a genetically complex
More about genes
TS is neither a dominant nor recessive disorder.
o A carrier has an ~50% chance of passing genes associated
with TS to his/her children, but TS symptoms are not always
It may show up as a milder tic disorder, or as Obsessive
Compulsive Disorder or Attention Deficit Disorder with or without
the association of tics.
Pedigree analysis is not applicable to TS because the disorder is
passed through many different genes on different chromosomes.
Tics- Sudden brief, irregular movements or sounds. Range from mild to
Premonitory urge-An uncomfortable bodily sensation (itch, tingle or tension)
that is relieved by expressing a tic.
Sudden, brief, and repetitive. Involve few
Distinct, coordinated patterns of movements.
Involve many muscle groups.
-Flapping the arms
-Touching the nose
tones of voice
Severe symptoms may greatly affect a person with
Tourette’s by interfering with communication, quality of life,
and daily functioning.
Tics are often worse with anxiety or excitement, and better
during calm and focused activities.
With extreme effort, some people can temporarily hold
their tics back until they find a less disruptive location to
express them, but this often causes tension to the point
where they feel like the tics must be expressed (against
Tourette’s is often linked with ADD and OCD
There are no blood, laboratory, or imaging tests available to diagnose
Both motor and vocal tics must be present, but not necessarily at the
Tics occur at least several times a day nearly every day or
intermittently for at least a year.
Tics cannot be caused by medications, other substances, or another
Often, patients receive a formal diagnosis long after their tics are
Many people with Tourette’s are self diagnosed after they, their
parents, other relatives or friends hear about Tourette’s from others.
There is no cure for Tourette’s, but the condition often
improves in the late teens or early 20’s.
It is a lifelong and chronic condition, but is not degenerative.
o People with Tourette’s have a normal life expectancy
Tourette’s Syndrome does not impair intelligence.
Neurobehavioral disorders that are associated with tourette’s
such as ADD, ADHD, OCD, depression, generalized anxiety,
panic attacks, and mood swings can persist in adult life even
though the severity of tics may lessen.
○ may be taken to minimize the impairment caused by
● Behavioral treatments
○ Awareness training and competing response training can
be used to reduce tics.
● Supportive therapy
○ Although this hasn’t been shown to reduce tics, can help
a person with Tourette’s better cope with the disorder
and the social and emotional problems that may occur
because of it.
Recent studies suggest that many slight genetic variations
add up to cause the symptoms that define Tourette
o Variations that may be associated with Tourette’s are
found on chromosomes 2, 3, 5, 7, 9, 11, 12, 16, and 20.
o Genes that may be associated with Tourette’s include
COL8A1 (chrom. 3) and, COL27A (chrom. 9) which
encode for collagens-proteins found in bone and in the
brain; POLR3B (chrom. 12) which encodes RNA
Polymerase III; as well as NRXN1 (chrom. 2) which
encodes the protein neurexin 1 that mediates cell
interaction within the brain.
Currently, genetic counseling isn’t very useful
because little is known about the specific genes
involved in TS. As more information is gathered
about TS genetics, genetic counseling will
Davis, L.K. et al (2013) Partitioning the heritability of Tourette Syndrome and Obsessive Compulsive
Disorder reveals differences in genetic architecture. PLoS Genet 9(10): e1003864.
Matthews, C (2009) Tourette Syndrome Genetics Q&A. Inside TSA, Winter 2009. http://www.tsausa.org/aMedical/medical_genetics.htm, accessed December 2, 2013.
Mayo Clinic (2012) Tourette Syndrome. http://www.mayoclinic.com/health/tourette-syndrome/DS00541,
accessed November 30, 2013.
Nag, A. et al (2013) CNV analysis in Tourette Syndrome implicates large genomic rearrangements in
COL8A1 and NRXN1. PLoS ONE 8(3): e59061. doi:10.1371/journal.pone.0059061
National Institute of Neurological Disorders and Stroke (2012). Tourette Syndrome Fact Sheet.
http://www.ninds.nih.gov/disorders/tourette/detail_tourette.htm#220463231, accessed November 30,
Scharf, J.M. et al (2013) Genome-wide association study of Tourette Syndrome. Mol Psychiatry. 2013
June ; 18(6): 721–728. doi:10.1038/mp.2012.69.