Koolen-de Vries Syndrome

What is Koolen-de Vries syndrome?

Koolen-de Vries syndrome (KdVS) is a rare genetic condition involving the 17th chromosome. It causes developmental delay, intellectual disability and distinctive facial features. You may first notice the condition if your child needs more time than others to sit up on their own, say their first words or take their first steps.

While symptoms vary from child to child, they shouldn’t stop your child from having a bright and cheerful personality. This is a common characteristic of the condition. But your child will need care throughout their life to manage any additional symptoms they may experience.

Another name for this condition is 17q21.31 microdeletion syndrome.

Symptoms of Koolen-de Vries syndrome

The most common symptoms of KdVS include:

• Cyclic vomiting syndrome
• Developmental delays
• Mild to moderate intellectual disabilities
• Weak muscle tone (hypotonia)

Some children may experience:

• Difficulty feeding (infants)
• Heart, bladder or kidney abnormalities
• Scoliosis
• Seizures
• Undescended testicles

Children with Koolen-de Vries syndrome are usually cheerful and friendly. But behavioral and neurodevelopmental conditions, including attention-deficit/hyperactivity disorder (ADHD) and autism spectrum disorder, may occur.

Koolen-de Vries syndrome facial features

Your child may have distinctive facial features with this condition, including:

• A long face
• A large forehead
• A pear-shaped nose
• Droopy eyelids (ptosis)
• Large, protruding ears
• Outer corners of their eyes point up
• Skin folds covering the inner corner of their eyes (epicanthal folds)

Koolen-de Vries syndrome causes

A genetic variation or deletion of the KANSL1 gene on chromosome 17 causes Koolen-de Vries syndrome. Most people with the condition (95%) are missing the KANSL1 gene from one copy of chromosome 17. This is called a microdeletion. The remaining children with the condition have a variation within the KANSL1 gene that causes one copy of the gene to not work as expected.

The KANSL1 gene is responsible for producing a protein that helps control gene activity (expression) by altering chromatin. Chromatin is the combination of protein and DNA that packages DNA into chromosomes. It plays an important role in the function and development of many body parts and systems.

How is Koolen-de Vries syndrome inherited?

KdVS is an autosomal dominant condition. A child could inherit this condition if one biological parent passes the genetic variation to them during conception. It only takes one genetic variation or deletion in each cell to cause it.

In some cases, the condition isn’t inherited but occurs randomly (de novo) during reproductive cell formation or early fetal development.

How doctors diagnose Koolen-de Vries syndrome

To diagnose this condition, your child’s provider will perform a physical examination and review their symptoms.

Genetic testing confirms the diagnosis. The type of genetic change will determine the type of testing. Chromosomal microarray is a technique that can show whether part of a chromosome is missing. Gene sequencing can show changes to the KANSL1 gene.

Every child with KdVS has different symptoms. Your child may have a variety of additional tests to help determine the extent of their condition. These tests may include:

• Developmental evaluation
• Echocardiogram
• Feeding assessment
• Kidney ultrasound
• Magnetic resonance imaging (MRI)
• X-rays

Koolen-de Vries syndrome treatment

Koolen-de Vries syndrome treatment may include a variety of options depending on your child’s needs. Your child’s providers will most likely recommend several types of therapy, including:

• Occupational therapy. Occupational therapy helps your child develop their fine and gross motor skills.
• Physical therapy. A physical therapist will work with your child to help them strengthen their muscles.
• Speech therapy. Speech therapy can help your child with their communication skills by using a variety of techniques, including pictures, sign language and speech devices.

Depending on your child’s symptoms, they may need additional treatment, including:

• Antiseizure medication
• Placement of a feeding tube for nutritional challenges
• Surgery for conditions like scoliosis or undescended testicles

Children may need support in different learning environments. Some children do well in traditional schools, but others need special assistance.

What is Koolen-de Vries syndrome life expectancy?

Researchers don’t know the exact life expectancy for people with Koolen-de Vries syndrome. But survival into adulthood is typical.

What can I expect if my child has Koolen-de Vries syndrome?

Life for children with Koolen-de Vries syndrome can vary depending on the severity of symptoms. Your child may have frequent medical appointments with different healthcare providers to help manage their condition. Therapy and medication may become a major part of your child’s life. In some cases, your child may not need to see their providers or participate in different therapies as much as others diagnosed with the same condition.

You can help your child by making sure they receive the support they need in school. Specialized classes may be necessary. Talk to your child’s teachers and school to get the resources they need. For example, if your child has speech issues, make sure they’re working with a speech therapist.

Most adults with KdVS aren’t able to live independently. This is something their caregivers and providers will need to evaluate on a case-by-case basis.