Koolen De Vries Syndrome

Overview

Koolen-de Vries syndrome (say: KOO-len de VREES) is a rare genetic condition that a person is born with. It is caused by a tiny change in a person's DNA — the instruction manual our bodies use to grow and work. In most people with this syndrome, a very small piece of chromosome 17 is missing. In others, there is a small change in a gene called KANSL1, which sits in that same part of chromosome 17. Because genes help the brain and body develop, this change can affect learning, speech, muscle tone, growth, behaviour and sometimes the heart, kidneys, eyes or hearing. Every person with Koolen-de Vries syndrome is different — some are only mildly affected and some need a lot more support. It is not an illness you catch, and it is not caused by anything a parent did or did not do during pregnancy.

It is very rare. Experts estimate it affects roughly 1 in 16,000 to 1 in 20,000 people, though the true number is not known and some people are never diagnosed. Rare conditions can feel isolating, but specialist teams do see and support people with this syndrome regularly.

It affects boys and girls equally, and people of every ethnic background. The genetic change is present at birth, so signs usually appear in the first year or two of life — often as floppy muscles, feeding difficulties or delayed speech. Some people are only diagnosed later, in childhood or even adulthood, especially when features are mild. It is not contagious and cannot be passed on like a cold.

Symptoms

Common symptoms

• Developmental delay — sitting, walking, talking or learning skills arrive later than expected
• Speech and language delay, which is often the most noticeable feature
• Low muscle tone (hypotonia), so the baby feels floppy or 'slips' when held
• Feeding difficulties as a baby, such as slow feeding or poor weight gain
• A friendly, sociable, happy manner that is often commented on by families and teachers
• Learning difficulties of varying degree, from mild to more significant
• Sleep problems, including trouble falling asleep or waking often
• Behaviour that can include short attention span, anxiety or features similar to autism

Symptoms in children

• Floppy muscles and slightly delayed head control in the first months
• Late first words and short sentences; speech therapy is often needed
• Walking may be delayed, and some children are a little unsteady
• Seizures (fits) in some children — these need to be checked by a doctor
• Heart murmurs or heart defects found on a heart scan
• Kidney or urinary tract differences found on a scan
• Reflux and constipation
• Vision problems such as squint (eyes not lining up) or needing glasses
• Hearing loss in some children
• Curved spine (scoliosis) or loose, flexible joints
• Small stature compared with other children of the same age

Symptoms in older adults

• Many adults with the syndrome were diagnosed as children, but some are diagnosed later in life
• Ongoing learning support needs, often with good independence in daily skills
• Anxiety, low mood or sleep difficulties that deserve proper assessment and support
• Curved spine, joint problems or muscle weakness that may need physiotherapy
• Weight gain, especially if mobility or exercise is limited
• Some adults need help with money, work, health appointments or decision-making
• Regular health checks are still important — adult doctors may not know this rare condition, so bring your records

Causes

Main causes

• In most people, a tiny piece of chromosome 17 is missing (called a 17q21.31 microdeletion). Chromosomes are the packages of DNA we inherit — a 'microdeletion' means a very small part of the package is absent.
• In others, there is a small change (variant) in the KANSL1 gene, which affects how the gene works.
• These genetic changes usually happen by chance in the egg or sperm, or very early in development. They are not caused by anything parents did.
• In a small number of families, the change is inherited from a parent — sometimes a parent has a rearrangement of their chromosomes and is healthy themselves.

Risk factors

• Having a parent or close family member with the same genetic change (this is uncommon)
• A parent carrying a 'balanced translocation' — a re-arrangement of chromosomes that causes no problems for them but can affect a child
• There is nothing you can do or avoid during pregnancy that is known to cause this syndrome

When to see a doctor

See a doctor urgently if:

• A baby who is very floppy, feeds poorly, or is not gaining weight
• Any seizure (fit) — this always needs to be checked the same day
• Loss of skills the child used to have, such as words or walking
• Breathing problems, choking with feeds, or repeated chest infections
• A swollen tummy, no bowel movement for several days, or severe constipation with pain

Book a routine appointment if:

• You are worried about your child's speech, walking, learning or behaviour
• Your child seems much shorter or smaller than others of the same age
• Sleep problems that are affecting the whole family
• Concerns about eyesight, hearing, or frequent ear infections
• New anxiety, low mood, or behaviour changes at home or school
• You want to discuss family planning or genetic testing for relatives

Diagnosis

The diagnosis is made with a genetic test, usually from a blood or saliva sample. A doctor — often a paediatrician (children's doctor) or a clinical geneticist (a doctor specialising in inherited conditions) — will examine your child, ask about their development and health, and arrange the test. Because the features can be subtle, some people are diagnosed only after several appointments, and the wait can feel frustrating.

Tests that may be done

• Chromosomal microarray (also called array CGH) — a detailed scan of the chromosomes that can find the small missing piece on chromosome 17
• KANSL1 gene testing — used when the microarray is normal but the syndrome is still suspected
• Testing of parents, to see whether the change was inherited or happened by chance
• Heart ultrasound (echocardiogram) to check the heart's structure
• Kidney and bladder ultrasound
• Hearing tests and eye checks
• Blood tests for general health, and sometimes thyroid or other hormone checks
• EEG (brain wave test) if seizures are suspected
• Developmental and speech assessments to plan support

What to expect at your appointment

Results can take several weeks. You will usually be offered a appointment with a genetics team to explain what the result means, what health checks are recommended, and what it may mean for other family members. You may feel a mix of relief and worry — both are normal. Write down your questions beforehand and bring someone with you if you can. Ask for the information in writing, and ask who to contact afterwards if new questions come up.

Treatment

There is no cure for Koolen-de Vries syndrome, and no single medicine treats it. Instead, care is 'supportive' — meaning a team works with the person and family to build skills, treat specific health problems if they appear, and make daily life easier. The team often includes a children's doctor, a geneticist, physiotherapists, speech and language therapists, occupational therapists, a heart doctor, a kidney doctor, and education or learning support staff. Care is tailored to the individual, because two people with the same genetic change can have very different needs.

Self-care at home

• Keep a simple health record or folder with letters, test results and contact details, and bring it to every appointment
• Keep a diary of seizures, sleep patterns or behaviour to help doctors see patterns
• Build in predictable routines for sleep, meals and activities — this helps many children feel calmer
• Use visual aids, short instructions and lots of repetition to support communication at home
• Ask about early intervention services — physiotherapy, speech therapy and occupational therapy work best when started young
• Make sure everyone involved (nursery, school, childminder) knows about the diagnosis and any health plan
• Look after yourself too — caring for a child with extra needs is hard work, and your wellbeing matters

Medical treatments

Treatment is planned around the person's specific needs. Physiotherapy helps with muscle tone, movement and posture. Speech and language therapy supports communication, sometimes with signing or picture systems. Occupational therapy helps with daily skills like dressing, feeding and handwriting. Seizures are assessed and managed by a neurologist (a brain and nerve specialist). Heart, kidney, eye and hearing problems are checked regularly and treated by the relevant specialists. Behavioural and emotional difficulties may be supported with psychology input, sleep advice, and structured routines at home and school. Educational support is planned with the school, and some children benefit from a statement or plan of extra help. Medicines are sometimes used for specific problems such as seizures, constipation or sleep, and these decisions are always made by your own medical team — never start, stop or change any medicine without asking them.

When is surgery considered?

Most people with this syndrome do not need surgery. Surgery may be considered for certain heart defects, for a curved spine (scoliosis) that is getting worse, or for other specific problems found on tests. These decisions are made by specialist teams together with the family, and are based on the individual's health, age and the risks and benefits of the operation.

Living with this condition

Daily life with Koolen-de Vries syndrome usually means a mix of ordinary family routines and some extra planning. Many children thrive on predictability — knowing what happens next, with clear, calm warnings before changes. Communication can be supported with pictures, simple short sentences and time to respond. Mealtimes may need extra patience, and constipation is common, so fluids, fibre and routine toilet times help. Sleep can be challenging; a calm, consistent bedtime routine and a dark, quiet room make a real difference. As children grow, planning for school support, hobbies, friendships and gradually building independence all become part of everyday life.

Lifestyle tips

• Encourage movement and play — swimming, walking and soft play suit many children with low muscle tone
• Keep to regular routines for meals, sleep and activities
• Keep appointments for heart, kidney, eye, hearing and growth checks even when your child seems well
• Build a support network of family, friends, school staff and other families who understand
• Plan ahead for transitions — starting school, changing classes, moving to adult services
• Ask about financial and practical support available where you live, such as disability benefits or carer support

Diet and exercise

There is no special diet for this syndrome. A balanced, varied diet with plenty of fluids and fibre helps with the constipation that many people experience. If feeding is difficult, a speech therapist or dietitian can advise on textures, positioning and ways to make mealtimes safer and easier. Some people gain weight easily, particularly if they are less active, so gentle, regular activity is encouraged. Physiotherapy and occupational therapy can suggest exercises suited to the person's strength and mobility — swimming and walking are often good choices. Always check with your own team before starting a new exercise plan, especially if there are heart or spine concerns.

Mental health and emotional wellbeing

A rare diagnosis affects the whole family. Parents and carers often feel shock, grief, exhaustion, guilt and worry — these feelings are valid and very common, and they do not mean you are coping badly. Children and young people with the syndrome may experience anxiety, low mood, frustration or behaviour that is hard to manage, and this deserves the same attention as physical health. Talking to a psychologist, counsellor or family support worker can help a great deal, as can connecting with other families. If you or your child ever feel overwhelmed, hopeless, or at risk of harm, contact your local emergency number or a crisis support service straight away — you deserve urgent help, and asking for it is a sign of strength.

Prevention

Koolen-de Vries syndrome cannot be prevented. It happens because of a genetic change that is usually not inherited and is not linked to anything a parent did, ate, drank or was exposed to during pregnancy. What can be done is planning: genetic counselling can explain the chance of the condition affecting another child in the family, and can discuss testing options for future pregnancies.

Screening programmes

There is no routine screening for this syndrome in pregnancy or in newborns. If a close family member is known to have the genetic change, genetic counselling can discuss testing options before or during a pregnancy. After diagnosis, regular checks of the heart, kidneys, eyes, hearing, growth, spine and development act as 'screening' for problems that can be helped if found early.

Complications

If left untreated

• Speech and learning difficulties may become harder to manage without early therapy and school support
• Seizures that are not recognised and treated can affect safety and learning
• Heart defects or high blood pressure in the lungs can worsen if not monitored
• Kidney and urinary problems can lead to infections or long-term kidney damage if missed
• Untreated constipation, reflux or feeding difficulties can affect growth and comfort
• A curved spine can progress during growth spurts if not watched
• Hearing and vision problems can hold back communication and learning if not corrected
• Anxiety, sleep problems and behavioural difficulties can build up without support for the child and family

Long-term outlook

The outlook varies a lot from person to person, and it is honest to say that no one can predict exactly how a particular child will develop. What is clear is that early therapy, good health checks, the right school support and a strong family network make a real difference. Many children learn to walk, communicate and take part in family and community life, and many adults live with some support while enjoying work, hobbies and relationships. Most people with the syndrome have a normal lifespan, although this depends on any heart or other health problems. Families often say that the biggest difference is made by steady, patient support and by celebrating progress at their child's own pace.

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