Koolen–De Vries Syndrome Awareness Day Date in the current year: July 17, 2025

Koolen–De Vries syndrome (KdVS), formerly known as 17q21.31 microdeletion syndrome, is a rare genetic disorder caused by the deletion of a segment of chromosome 17, which can affect up to six different genes, including the KANSL1 gene. The disorder can also be caused by a mutation in the KANSL1 gene.

In most cases, KdVS results from a de novo (spontaneous) microdeletion or mutation that occurs during fetal development. The disorder has an autosomal dominant inheritance pattern, meaning one defective copy of the KANSL1 gene is enough to cause the syndrome. Therefore, if a patient with Koolen–De Vries syndrome has a child, there is a 50% chance that the child will inherit the disorder.

Symptoms of Koolen–De Vries syndrome can vary greatly depending on which genes are affected. Some common signs and symptoms include:

• Low birth weight (less than 2,500 grams, regardless of gestational age)
• Hypotonia (low muscle tone) at birth
• Poor feeding in infancy
• Poor coordination (dyspraxia)
• Moderate developmental delays and learning disabilities
• Seizures (in some cases only)
• Heart defects
• Kidney/urological problems

Since the symptoms of Koolen–de Vries syndrome are not specific to the syndrome and can vary greatly, genetic testing is necessary for diagnosis. Due to its rarity, recent discovery (in 2006), and lack of access to genetic testing in some regions, Koolen–de Vries syndrome is thought to be underdiagnosed. This suggests that its prevalence may be higher than currently estimated.

There is no cure for Koolen–de Vries syndrome. It is a lifelong condition that requires continuous management. However, early intervention, proper medical care, and educational support enable many patients with KdVS to live fulfilling lives. Some patients may be able to live independently, while others will require varying degrees of support throughout their lives.

Management of Koolen–de Vries syndrome usually includes physical therapy to address feeding problems and delays in motor development. Some patients may require a feeding tube temporarily. As the child grows, physical therapy focuses first on strengthening muscles to improve tone and then on developing fine and gross motor skills. Patients also need occupational and speech therapy. Some patients require specialized medical care to treat specific symptoms, such as seizures, heart defects, or urological problems, if those symptoms manifest.

KdVS Awareness Day promotes public awareness of the syndrome, shows support for those impacted by it, and highlights the importance of early diagnosis and intervention. You can get involved by learning more about Koolen–De Vries syndrome and sharing what you’ve learned with others. You can also donate to the KdVS Foundation or another organization that supports patients with KdVS and spread the word on social media using the hashtags #KdVS and #KdVSAwareness.