Childhood disintegrative disorder (CDD) is a very rare brain and development problem in children. A child grows and learns normally for at least the first 2–3 years. Then, between about 3 and 10 years old, the child suddenly starts to lose skills they already learned, such as speech, play, toileting, and social skills. Patient+1
Childhood disintegrative disorder (CDD), also called Heller’s syndrome, is a very rare condition where a child develops normally for at least 2–3 years and then loses skills in many areas such as language, social interaction, play, and self-care. Today, most doctors group CDD under the wider diagnosis “autism spectrum disorder (ASD)” in DSM-5, and treatment is usually the same as for autism, with a strong focus on education, behaviour therapy, and support for the family. There is no single cure, so care aims to improve day-to-day life, communication, and comfort. PMC+2
CDD is now included inside “autism spectrum disorder” (ASD) in the DSM-5 book that doctors use for mental health diagnoses. So today many doctors say “autism with severe regression” instead of giving a separate CDD label, but the pattern of sudden loss of skills is still very important. dchealthcheck.net+1
CDD is extremely rare. Studies suggest it may affect only about 1–2 children in every 100,000. Most children keep severe disability in thinking, language, and social skills and need long-term support. Wikipedia+2achievebeyondusa.com+2
Another names
CDD has been described in the medical literature for more than 100 years. It was first written about by Theodor Heller in 1908, so older books often use his name for the condition. Wikipedia+1
Other names (synonyms)
Doctors and books may use these other names for the same pattern of illness: Wikipedia+1
Heller’s syndrome
Disintegrative psychosis
Dementia infantilis (old term, now rarely used)
Childhood disintegrative disease
“Autism with late regression” (descriptive term, not a formal code)
All of these names describe a child who was doing fairly well and then shows strong loss of skills in language, social life, and daily living. Wikipedia+1
Types (clinical patterns)
There is no official list of “types” of CDD in DSM-5. However, doctors sometimes talk about patterns that help them think about causes and tests. These are not strict categories, but they help us explain the condition in simple language. ScienceDirect+1
Idiopathic CDD – “Idiopathic” means that no clear cause is found, even after many tests. The child has the classic pattern of normal early development followed by strong loss of skills and autism-like behavior. RCPCH
CDD linked with seizures – Some children with CDD also have epilepsy (repeated seizures). Their EEG test often shows abnormal brain electrical activity, so doctors think the seizures may be related to the regression. PMC+2ResearchGate+2
CDD linked with metabolic or storage diseases – A few children with a CDD-like pattern are later found to have metabolic problems or “storage diseases,” where harmful substances build up in the brain and nerves. Wikipedia+1
CDD after brain infection or inflammation – Rarely, a child may develop CDD-like regression after infections such as measles brain infection (subacute sclerosing panencephalitis) or other severe brain inflammation. Wikipedia+2Frontiers+2
CDD overlapping with regressive autism – Some children with autism also lose skills after a period of normal or near-normal development. These cases can look very similar to CDD, so many experts now see CDD as part of the wide autism spectrum. Wikipedia+2Medical News Today+2
Causes of childhood disintegrative disorder
Doctors do not know one single cause of CDD. Many children with CDD have completely normal medical tests. Still, research shows several conditions and risk factors that may be linked to the disorder. Most of these are “possible” or “suspected” causes, not proven in every child. Lumen Learning+1
Unknown brain development problem
In many children, no clear cause is found. Doctors think something goes wrong in how the brain cells connect and talk to each other during early childhood, but current tests are not sensitive enough to show it exactly. Wikipedia+1Genetic vulnerability
Some children with CDD have family histories of autism or other developmental disorders. This suggests that genes may make the brain more fragile to other stresses, even though no single “CDD gene” has been found. Lumen Learning+1Family history of autism spectrum disorder
Studies show that autism and CDD can occur in the same families. This supports the idea that CDD may share genetic risk factors with autism, but with a more severe and late-regression pattern. Wikipedia+1Seizure disorders (epilepsy)
Many children with CDD also have seizures, and their EEG tests show abnormal brain electrical activity. It is not clear if epilepsy causes CDD or if both come from the same brain problem, but the link is strong. PMC+2ResearchGate+2Metabolic disorders
Some children who look like they have CDD are later found to have metabolic diseases, where the body cannot handle certain proteins, fats, or sugars. These problems can damage brain cells and lead to loss of skills. Frontiers+1Lipid storage diseases
In lipid storage diseases, fats build up in brain and nerve cells. A few case reports show children with these diseases losing language and social skills in a way that looks like CDD. Wikipedia+1Subacute sclerosing panencephalitis (SSPE)
SSPE is a long-lasting brain infection caused by a late effect of measles virus. Children with SSPE can have behavior changes and loss of skills similar to CDD, so doctors always check for serious infections in children with regression. Wikipedia+1Other chronic brain infections
Brain infections like encephalitis or, more rarely, HIV infection can damage areas of the brain that control language and social skills, leading to regression that looks like CDD. Wikipedia+1Neurodegenerative diseases
Some slow, progressive brain diseases cause children to lose late-acquired skills. In early stages, they may be mis-labeled CDD until further tests show the underlying degenerative disease. Wikipedia+1Brain tumors
A tumor in certain brain regions can cause behavioral change and skill loss. Because of this, doctors often order brain imaging to rule out tumors when a child shows sudden regression. Wikipedia+1Immune-mediated brain inflammation
In some cases, the body’s immune system mistakenly attacks the brain (autoimmune encephalitis). This can rapidly change behavior, language, and movement, so doctors think about this when evaluating CDD-like symptoms. FrontiersPrenatal viral infections
Exposure to certain infections during pregnancy may affect brain development and increase the risk of autism-spectrum conditions, including CDD-like regression, though this is not proven for every infection. asdclinic.co.uk+1Birth trauma and lack of oxygen
Difficult labor, lack of oxygen at birth, or serious newborn complications may injure the brain. Some children with these early problems later show strong developmental regression, though the link to CDD is not always clear. asdclinic.co.uk+1Exposure to toxins (e.g., lead, mercury)
Heavy metals and other toxins can damage a child’s developing brain and cause loss of skills, so doctors often test for lead or similar toxins to rule out these treatable causes of regression. Wikipedia+1Very premature birth and low birth weight
Being born very early or very small can affect brain development and raise the risk of later neurological and developmental problems, including severe autism-spectrum symptoms. Lumen Learning+1Structural brain abnormalities
MRI scans in some children with CDD show subtle changes in brain structure or white matter. These findings suggest that the “wiring” of the brain may be abnormal even before the regression becomes obvious. PMC+1Abnormal EEG patterns without seizures
Some children have abnormal electrical brain activity on EEG even when they do not have clinical seizures. These patterns may disturb normal communication between brain networks and contribute to regression. PMC+1Other medical or genetic syndromes
CDD-like regression has been reported in children with certain rare genetic syndromes. In these cases, the syndrome may be the main cause, and CDD-type symptoms are part of a wider pattern. malacards.org+1Combination of genes and environment
Most experts believe that no single factor explains CDD. Instead, sensitive genes plus environmental stresses (infection, toxins, medical problems) may together overload the child’s brain and lead to sudden loss of skills. Lumen Learning+1Still-unknown causes
Even with careful tests, many children with CDD have no clear medical explanation. This shows how much we still have to learn about brain development, and why ongoing research is so important. RCPCH+1
Symptoms of childhood disintegrative disorder
CDD always includes regression. This means a child loses skills that they had already learned and used for some time. The change often happens over weeks or months, and it can be very shocking and painful for families. Wikipedia+1
Loss of spoken words
The child may stop using words they knew well before. For example, a child who used phrases like “I want juice” may go back to single sounds or become almost silent. Wikipedia+1Loss of understanding of language
The child may no longer follow simple instructions or understand everyday speech, even if hearing tests are normal. They may seem “far away” or not respond when called by name. Wikipedia+1Loss of social interest
A child who used to make eye contact, smile, and play with family may begin to avoid people. They may seem withdrawn, prefer to be alone, or appear to ignore others. Wikipedia+1Loss of play skills
Before regression, a child may enjoy pretend play, like feeding a doll or driving toy cars. After regression, they may only do simple, repetitive play, such as spinning wheels or lining up objects. Wikipedia+1Loss of toilet control
A toilet-trained child may start wetting or soiling again, both during the day and at night. This loss of bowel and bladder control is a key feature in classic CDD descriptions. Wikipedia+1Loss of self-care skills
Children may forget how to dress themselves, brush their teeth, or feed themselves with a spoon, even though they did these tasks well before. Parents often notice this strongly in daily life. Wikipedia+1Loss of motor skills
Some children lose coordination. They may stumble, have trouble climbing stairs, or stop using fine hand skills like drawing or building. Wikipedia+1New repetitive movements
After regression, children often develop repetitive behaviors, such as hand-flapping, rocking, or spinning. These behaviors are similar to those seen in autism. Wikipedia+2Medical News Today+2Narrow and fixed interests
The child may focus on a few objects or topics and resist any change. They may watch the same video again and again or become very upset when routines change. Wikipedia+1Unusual responses to sound, light, touch, or smell
Some children show strong reactions to normal sounds or lights, or seem not to notice pain or temperature normally. This “sensory difference” is common in autism and also seen in CDD. Wikipedia+1Sleep problems
Children may have trouble falling asleep, wake often at night, or have very irregular sleep patterns. Poor sleep can worsen daytime behavior and learning problems. ButterflyLearnings+1Irritability and tantrums
Because the child cannot communicate well, they may cry, scream, or show aggression when frustrated or confused. Families often notice more frequent and intense tantrums after regression. PMC+1Anxiety or fear
Some children seem very anxious, clingy, or scared. They may resist leaving home or entering new places, possibly because they are confused by their own loss of skills. PMC+1Seizures
A number of children with CDD also have epileptic seizures. Seizures may appear around the same time as the regression or later, and they may range from brief staring spells to full-body convulsions. PMC+1Drop in school performance
As language, attention, and thinking skills decline, teachers and parents see a clear drop in school work and learning. The child may no longer follow classroom routines or instructions. Wikipedia+1
Diagnostic tests for childhood disintegrative disorder
There is no single blood test or scan that proves CDD. Diagnosis is based mainly on a careful history of normal early development followed by strong regression in many skills, along with autism-like behaviors. Tests are used to rule out other causes and to understand the child’s needs. Wikipedia+2buildingblockstherapy.org+2
Physical exam tests
Full physical examination
The doctor checks the child’s overall health, including heart, lungs, abdomen, skin, and general behavior. This helps find signs of infection, chronic illness, or genetic syndromes that might explain the regression instead of CDD. Lumen Learning+1Growth and head size measurement
The doctor measures height, weight, and head circumference and compares them with age charts. Abnormal growth or very small or large head size can point to genetic or brain development problems. Lumen Learning+1Detailed neurological examination
The neurologist checks muscle tone, reflexes, balance, strength, eye movements, and coordination. Abnormal findings guide further tests for degenerative diseases, tumors, or other brain disorders. PMC+1Clinic observation of behavior and development
During the visit, the team watches how the child moves, plays, and interacts. They note social contact, language use, repetitive behaviors, and how the child manages tasks, which helps distinguish CDD from other conditions. Wikipedia+2Medical News Today+2
Manual / clinical assessment tests
Developmental screening questionnaires
Parents may fill forms such as general developmental checklists or autism screeners (like M-CHAT-R/F). These tools help flag delays and autism-like behavior quickly, but they are not enough alone for a diagnosis. Autism Speaks+1Autism observation assessment (e.g., ADOS-type tools)
A trained specialist plays and talks with the child in a structured way and scores social, communication, and repetitive behaviors. This kind of direct observation is a core part of modern autism and CDD evaluation. PMC+1Parent developmental history interview (e.g., ADI-R-type)
A detailed interview with caregivers collects clear timelines for when skills were gained and lost. For CDD, it is very important to show at least two years of near-normal development followed by strong regression after age three. Wikipedia+1Speech and language evaluation
A speech-language therapist tests understanding, expression, and social use of language. They check whether the child’s language loss is global (across all areas) and help plan therapy based on strengths and weaknesses. Athena Care+1
Lab and pathological tests
Complete blood count (CBC) and basic chemistry panel
These simple blood tests look for anemia, infection, electrolyte problems, and organ function. Abnormal results may suggest medical illnesses that affect brain function and behavior. Frontiers+1Thyroid function tests
Thyroid hormones strongly affect brain development. Low or high thyroid levels can cause behavior changes and learning problems, so doctors often check thyroid function in children with regression. Frontiers+1Blood lead level and heavy metal tests
Lead and other heavy metals can poison the brain and cause language and behavior problems. Testing for these toxins helps rule out treatable environmental causes of regression. Wikipedia+1Metabolic screening tests
Blood and urine tests may look for abnormal amino acids, organic acids, lactate, ammonia, or other markers of metabolic disease. If these are abnormal, more specific tests are done to confirm conditions that can mimic CDD. Frontiers+1Genetic testing – chromosomal microarray
A chromosomal microarray looks for small missing or extra pieces of chromosomes. Such changes are common in children with developmental disorders and can point to a specific syndrome behind the regression. malacards.org+1Genetic testing – single-gene or gene panel tests
If doctors suspect certain syndromes (for example, fragile X or other known autism-linked genes), they may order special DNA tests or gene panels. Finding a genetic cause helps with counseling and future planning. malacards.org+1
Electrodiagnostic tests
Standard EEG (electroencephalogram)
EEG records the brain’s electrical activity using small electrodes on the scalp. Many children with CDD have abnormal EEG patterns, with or without obvious seizures, so EEG is a key test. PMC+2ResearchGate+2Sleep-deprived or overnight video EEG
Sometimes abnormal brain activity appears only during sleep. A longer EEG with video helps capture hidden seizures or patterns that may explain sudden regression or behavior changes. Frontiers+1Evoked potentials (especially auditory)
Evoked potentials measure how the brain responds to sounds or visual signals. These tests can show whether sensory pathways are working normally and sometimes help separate hearing problems from language-processing problems. Frontiers+1
Imaging tests
Brain MRI (magnetic resonance imaging)
MRI uses magnets and radio waves to take detailed pictures of the brain. It can show structural changes, tumors, scars, or patterns of degeneration that might be causing the child’s regression, so it is often recommended. Frontiers+2buildingblockstherapy.org+2Brain CT scan
CT uses X-rays to create brain images. It is less detailed than MRI but faster and sometimes used in emergency situations to look for bleeding, large tumors, or major structural problems. Frontiers+1Functional imaging (PET or SPECT) in special cases
In rare, complex cases, doctors may use PET or SPECT scans to look at how different parts of the brain use sugar and blood flow. These tests are mainly used in research or in difficult epilepsy cases, not in every child with CDD. Frontiers+1
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Last Updated: December 31, 2025.
