Koolen de Vries syndrome

What causes Koolen de Vries syndrome?

Koolen de Vries syndrome is caused by either:

  • Mutations in the KANSL1 gene, resulting in the loss of function of this gene.
  • Loss (deletions) of a small amount of genetic material (microdeletion) from chromosome 17, that includes the KANSL1 gene.

Most of the cases are due to the microdeletion. The microdeletion occurs on the long (q) arm of chromosome 17 at a location q21.31. While the exact size of the deletion varies among individuals, most are missing several genes. However, because people with KANSL1 gene mutations have the same signs and symptoms as those with the microdeletion, researchers have concluded that the loss of this gene accounts for the features of this disorder.

The KANSL1 gene provides instructions for making a protein that helps regulate gene activity (expression) by modifying chromatin. Chromatin is the complex of DNA and protein that packages DNA into chromosomes. The protein produced from the KANSL1 gene is involved in controlling the activity of other genes, and in the development and function of many parts of the body. The relationship of KANSL1 gene loss to the specific signs and symptoms of Koolen de Vries syndrome is unclear.

Last updated on 05-01-20

How might Koolen de Vries syndrome be diagnosed?

The symptoms are very variable. Besides developmental delay and intellectual disability, no single clinical feature is required to establish the diagnosis, although childhood low muscle tone (hypotonia) is a common feature, reported in almost all affected people.

To establish the diagnosis of the syndrome one of the following is needed:

  • A 17q21.31 microdeletion involving at least KANSL1
  • A mutation in the KANSL1 gene (through an exam known as sequence analysis)

Last updated on 05-01-20

How is Koolen de Vries syndrome inherited?

Most people with Koolen de Vries syndrome (KdVS) are the first person born in their family with the syndrome. So in almost every case, the parents of a child with KdVS do not have KdVS and therefore do not have a changed (mutated) or missing (deleted) copy of the KANSL1 gene. This is because the mutation or deletion happened by a chance mistake when the sperm or egg was being made. The chance this same mistake will happen again is low. So if a person without KdVS has a child with KdVS, the risk of having other children with the KdVS is low (probably less than 1 in 100).

If a person with KdVS has a child, then there is a 50% chance their child will have KdVS. This means that there is also an equal chance (also 50%) of having a child who does not have KdVS. In genetic terms, KdVS is called an autosomal dominant syndrome to describe the way it is inherited.

Last updated on 05-01-20

How might Koolen-de Vries syndrome be treated?

Treatment depends on the symptoms and may include:

  • Early intervention with physiotherapy for feeding problems and motor delay
  • Physical therapy aimed at strengthening the muscles
  • Therapy to improve development of the child's fine and gross motor skills
  • Speech therapy, sign language, pictures and computer touch screens aiming to improve communication skills
  • Educational programming directed to the specific disabilities identified
  • Routine antiepileptic drugs
  • Orthopedic care for scoliosis, hip dislocation, and positional deformities of the feet
  • Standard treatment for cardiac, renal, urologic, and other medical issues
  • Surgery cryptorchidism if indicated.

Affected people should have routine examinations by a primary care physician and pediatrician, cardiologist, nephrologist, and/or urologist. Referrals to other specialists is indicated if neurological or other problems are suspected.

Last updated on 05-01-20

Clinical Research Resources

17q21.31 Research Project

The 17q21.31 Research Project aims to better characterize the clinical spectrum of Koolen de Vries syndrome, to provide insights into the molecular effects of the 17q21.31 deletion and KANSL1 mutation, and to explore possibilities for treatment. These research studies are being conducted by investigators at the Department of Human Genetics, Radbound Univeristy Medical Center, Nijmegen, Netherlands and at the Department of Genome Sciences, University of Washington, Seattle, United States.

Last updated on 04-27-20

Where To Start

Unique - 17q21.31 microdeletion syndrome

Unique is a source of information and support to families and individuals affected by rare chromosome disorders. Click on the link to view information about 17q21.31 microdeletion syndrome.

Last updated on 04-27-20

Name: Chromosome Disorder Outreach CDO PO Box 724
Boca Raton, FL, 33429 , United States
Phone: +1-561-395-4252 Email: https://chromodisorder.org/contact/ Url: https://chromodisorder.org/
Name: Unique – Rare Chromosome Disorder Support Group G1, The Stables Station Road West
Surrey RH8 9EE
United Kingdom
Phone: +44 (0)1883 723356 Email: info@rarechromo.org Url: https://www.rarechromo.org/
Name: March of Dimes 1275 Mamaroneck Avenue
White Plains, NY, 10605, United States
Phone: 914-997-4488 Toll Free: 888-663-4637 Fax : 914-997-4763 Email: http://www.marchofdimes.com/contactus.html Url: http://www.marchofdimes.com/
Name: Koolen-de Vries Syndrome Foundation P.O. Box 470218
Fort Worth, TX, 76147, United States
Phone: 1-833-721-KDVS Email: https://kdvsfoundation.org/contact/ Url: https://kdvsfoundation.org/
Koolen DA & de Vries BBA. KANSL1-Related Intellectual Disability Syndrome GeneReviews. January 10, 2013; Reference Link

Connect with other users with Koolen de Vries syndrome on the RareGuru app

Do you have information about a disease, disorder, or syndrome? Want to suggest a symptom?
Please send suggestions to RareGuru!

The RareGuru disease database is regularly updated using data generously provided by GARD, the United States Genetic and Rare Disease Information Center.

People Using the App

Join the RareGuru Community

To connect, share, empower and heal today.

People Using the App