- A research team,
with members from multiple research centers, has identified four genes
that are involved in the development of Tourette syndrome.
- WWC1 is found to
have 90% probability in the development of the syndrome.
- Identification of
the cause will help in developing
effective treatment methods for the condition.
is characterized by involuntary motor and vocal tics with an
incidence of one in hundred
individuals worldwide. The cause behind this disorder has not been determined
so far, but a study by scientists from the Rutgers University, Massachusetts
General Hospital, Yale School of Medicine, UC San Francisco and the University
of Florida, detailed the identification of genes associated with the
development of the condition. The study was published in the journal Neuron
This is a significant step towards
identifying the mechanism of disease development which could be used for better
therapeutic strategies. The study helped in identifying
- The first "high-confidence" gene that
was found to increase the risk of Tourette syndrome
- Three other
probable risk genes
author of the study, Dr. Mathew State, who is a distinguished Professor and
chair of the Department of Psychiatry at UCSF, said that he was repeatedly
confronted with patients and families who experienced frustration because of
the poor understanding of the condition. According to Dr. State, the current
study is a major initial step into identifying risk factors, using the latest
‘WWC1, also called KIBRA, is a kidney and brain associated gene, that is found to be involved in the development of Tourette syndrome.’
Rare Variants to Identify Mechanism
The scientists had previously used
similar techniques to identify the genetic basis of autism spectrum disorders,
resulting in considerable advancements in autism research over the past five
order to identify rare variants, the regions of the genome that code for
protein were compared between Tourette affected children and their parents.
This step was carried out to identify new variations or mutations that are not
transmitted from parents, but those that occur at conception. The biological
effects of denovo variants or spontaneous variants are stronger than effects of
variants that have been passed down generations.
Jeremy Willsey who is the co-author of the study said that if the genes under
study were found to increase the risk for Tourette's syndrome, they could then
be used to develop better treatment methods.
Analyzing Genomic Data
genomic data was analyzed by the research team
- There were a total of 311
"trios" that comprised children who had Tourette disorder and
their parents who were mostly free from the disorder.
- The analysis
showed a strong association between de novo signaling and the disorder.
- A replication
study was carried out on 173
trios and the same results were obtained.
results of the study showed that
- 12 % of Tourette
disorder cases involved de novo variants.
- The de novo
variants affected nearly 400
different key risk genes.
Key Genes Associated With Tourette Disorder
The genetic data from the two studies
were combined, which led to the identification of four genes expressed in the
brain that were significantly associated with this disorder.
- WWC1: also known as KIBRA had a 90% probability of being
associated with Tourette's disorder. This gene is known to be involved in brain development, the
brain's response to estrogen and memory.
- FN1 and CELSR3: These are involved in brain circuitry development.
- NIPBL or
Delangin: NIPBL is involved in gene expression
regulation in the brain.
three genes have a 70% probability of resulting in the disorder.
gene is also involved in the development of
study was successful in identifying genes involved in Tourette syndrome due to
the collaborative efforts of researchers and clinicians, re-inforcing the need
for collaborative science and access to open data.
is a neurological disorder which is characterized by classic symptoms of
repetitive and involuntary movements, along with vocalizations called tics. It
is named after Dr. Georges Gilles de la
, who was a leading French neurologist and who first described the
condition in an old woman.
symptoms are initially identified between 3
and 9 years
and usually occur more often in males than in females. 50%
of the patients may also have
attention deficit hyperkinetic disorder. The voice tics include throat
clearing, snorting, sniffing, squeaking, grunting, sucking, puffing, barking
and other sounds. These tics are increased during periods of excitement and
lowered when carrying out an activity or sleeping.
- 200,000 Americans
have a severe form of Tourette syndrome
- One in a 100 people worldwide have mild
identification of the genes that are found to be involved in Tourette's
syndrome will help in developing effective treatment methods.
- Tourette Syndrome Fact Sheet - (http://www.indianjpsychiatry.org/article.asp?issn=0019-5545;year=2011;volume=53;issue=1;spage=66;epage=68;aulast=Raj)
- Tourette's disease with impulse control disorder - (https://www.ninds.nih.gov/Disorders/Patient-Caregiver-Education/Fact-Sheets/Tourette-Syndrome-Fact-Sheet)