This site was started on September 27, 2006 by concerned parents whose nine month old daughter was diagnosed with 1p36 Deletion Syndrome.

Without knowing where to turn or what to expect, the following information answers the most common questions about 1p36 Deletion Syndrome


What is 1p36 Deletion Syndrome?

1p36 Deletion Syndrome is a congenital genetic disorder characterized by moderate to severe intellectual disability, delayed growth, hypotonia, seizures, limited speech ability, malformations, hearing and vision impairment, and distinct facial features. The disorder is also known as monosomy 1p36.

The condition is caused by a deletion (loss of a segment of DNA) on the outermost band on the short arm (p) of chromosome 1. It is one of the most common deletion syndromes. It is estimated that the syndrome occurs in one in every 5,000 to 10,000 births. Knowledge of the disorder has increased a great deal over the last decade, mainly because more patients have been accurately diagnosed and described in international medical literature.

With 1p36 deletion syndrome a small amount of genetic material is missing (deleted) at the tip of chromosome 1. This condition causes birth defects, minor changes in physical appearance and mental retardation of varying degrees. All children with 1p36 deletion syndrome are unique; however, they share some of the common characteristics of 1p36 deletion syndrome listed below.

• Low muscle tone (congenital hypotonia):

Infants with 1p36 deletion syndrome often have low muscle tone, which may make it difficult for a newborn to suck and swallow.

Hypotonia (Low muscle tone) may also delay holding up head, sitting, crawling and walking. Muscle tone often improves with age and with physical therapy.


Seizure disorder:

Individuals with 1p36 deletion syndrome may have different types of seizures.

Most seizure disorders can be controlled with a diverse group of pharmaceuticals.

There are certain types of seizures, such as Myoclonic that have been show to be difficult to control with anticonvulsants.


• Growth/Feeding problems:

Infants with this condition often have difficulty gaining weight.

Some do not gain weight well because they have difficulty sucking and swallowing, while others may not grow well even though they are eating well.

Some older children with 1p36 deletion syndrome become overweight. Dietary changes, special feeding techniques or other medical interventions may be needed to manage the growth problems associated with this condition.


• Characteristic physical features:

Young children with 1p36 deletion syndrome tend to look similar. They often have a small head, a large fontanel (soft spot), deep-set eyes, short eye openings, a flat nose with a broad nasal tip, a prominent forehead, low set ears, ear asymmetry, a small mouth and a small pointed chin.


• Developmental delay:

Most young children with 1p36 deletion syndrome sit up, walk and talk later than usual. Speech is often more delayed than other skills. Many individuals with 1p36 deletion syndrome have difficulty talking and may benefit from the use of sign language or assisted communication devices. Early intervention services and intensive speech therapy are recommended to maximize an individual’s abilities.


• Mental retardation:

Older children and adults with 1p36 deletion syndrome have some degree of mental retardation, most commonly in the moderate to severe range. Some children with 1p36 deletion syndrome can talk and assist in their daily care, while others are not verbal and require constant care. Although the degree of mental retardation may be somewhat dependent on the size of the deletion, there is presently no way to accurately predict what an infant’s IQ will be when they grow up.


• Congenital malformations:

Babies with 1p36 deletion syndrome may be born with birth defects such as cleft lip, cleft palate, structural heart defects or malformations of the brain. Surgery may help correct some of these problems.


• Cardiomyopathy:

Some infants with 1p36 deletion syndrome have infantile ilated cardiomyopathy. With cardiomyopathy, the heart is enlarged and doesn’t pump as strongly as it should. When necessary, medication sometimes helps improve cardiac function.


• Hearing loss:

Conductive or sensorineural hearing loss occurs quite frequently in children with 1p36 deletion syndrome. Treatment for hearing loss is usually the same as it is for children with other causes of hearing loss.


• Vision or eye problems:

A number of different types of vision and eye problems have been reported in children with 1p36 deletion syndrome. Vision problems can usually be improved with glasses or other interventions.


• Thyroid problems:

Children with 1p36 deletion syndrome seem to be at an increased risk of developing thyroid problems, the most common being hypothyroidism. Hypothyroidism occurs when the thyroid gland doesn’t make enough of a hormone that is necessary for growth and development. When diagnosed, hypothyroidism can be treated successfully with medication.


• Behavior problems:

A number of behavior problems have been reported in children with 1p36 deletion syndrome. These include self-injuring behavior, banging or throwing objects, hitting people and screaming episodes. Child psychiatrists or psychologists can recommend strategies and medications that may help with behavior problems if they arise.


• Rare complications:

Additional, less common findings reported in children with 1p36 deletion syndrome include early onset of puberty (precocious puberty), abnormal curvature of the spine (scoliosis), minor vertebral abnormalities, and testes that have not descended into the scrotum at birth (cryptorchidism). Other uncommon medical complications may include neuroblastoma (a type of abdominal tumor that occurs almost exclusively in early childhood). Neuroblastoma is rare and has only been reported in a few children who have either 1p36 deletion syndrome or a chromosome rearrangement involving 1p36.


What causes 1p36 deletion syndrome?

1p36 deletion syndrome is caused by a missing piece (deletion) of chromosome material from the tip of the short arm of chromosome 1. Most people have 46 chromosomes. Chromosomes are arranged in pairs, with one copy of each pair coming from the mother and the other from the father. Chromosomes contain the genetic material that our bodies need to grow and develop. People with 1p36 deletion syndrome are missing some of the genetic material needed for normal development. Although we do not know exactly why chromosome deletions occur, there is no evidence that parents could have done anything to cause or prevent 1p36 deletion syndrome.


Is there a cure for 1p36 deletion syndrome?

No, unfortunately it is not possible to replace missing chromosome pieces. However, treatments are available for many of the problems associated with this condition.


How is 1p36 deletion syndrome diagnosed?

1p36 deletion syndrome is diagnosed by special laboratory testing. The deletion may be identified in the laboratory with high-resolution chromosome analysis or a test called FISH (fluorescent in-situ hybridization). FISH is used to detect missing pieces of chromosome material that are too small to be seen with a microscope during routine chromosome analysis. These tests might not be ordered unless the physician caring for the child recognizes the features of 1p36 deletion syndrome in the child.


How will making this diagnosis help my child and my family?

Making a diagnosis of 1p36 deletion syndrome is important in several ways. Knowing your child has 1p36 deletion syndrome allows you and your child’s physicians to plan for the child’s specific medical needs. A diagnosis can also help physicians recognize and treat problems early. A specific diagnosis allows for educational planning with special emphasis on speech and language problems. And making this diagnosis allows for accurate genetic counseling and the option of prenatal testing in future pregnancies.


Chromosome 1


Short arm (p) - Long arm (q)

A Normal chromosome 1

B Chromosome 1 with a deletion of 1p36


What specialists are needed to care for my child?

A team of doctors and medical specialists is needed to care for many children with 1p36 deletion syndrome. In addition to the child’s pediatrician, members of this team may include a medical geneticist; cardiologist; neurologist; gastroenterologist; ENT; ophthalmologist; nutritionist; and physical, occupational and speech therapists. Other specialists may also be needed depending on the child’s specific needs.


What are the health care guidelines for children with 1p36 deletion syndrome?

Because 1p36 deletion syndrome is a recently recognized condition, there are no standardized health care guidelines available. Recommendations, however, often include the following:


 An echocardiogram (ultrasound) of the heart to determine if there is a heart defect or cardiomyopathy

 An eye exam to determine if there are any vision or eye problems

 A complete hearing test (including high frequencies) to detect hearing loss

 A CT scan or MRI of the brain to rule out brain malformations

 Evaluation of feeding and growth as a newborn, and at regular intervals during childhood

•  Developmental assessments with speech, physical and occupational therapists

 Blood tests for thyroid dysfunction at birth and six months of age, and then annually


Will my future children have 1p36 deletion syndrome?

Most of the time, 1p36 deletion syndrome is not inherited, and is not likely to happen again with future children. Occasionally, a parent may have a chromosome rearrangement that significantly increases the chances of having another child with 1p36 deletion syndrome. All parents of children with 1p36 deletion syndrome should have genetic counseling, and should undergo chromosome analysis and FISH testing to determine if they have a chromosome rearrangement.


Can 1p36 deletion syndrome be detected in future pregnancies?

Yes, 1p36 deletion syndrome can be identified prenatally with FISH testing through amniocentesis or chorionic villus sampling (CVS). A genetic counselor can explain the potential risks and benefits of these procedures.


How can I talk to other parents who have children with 1p36 deletion syndrome?

Most genetics centers know families who have children with 1p36 deletion syndrome who would like to talk to other parents. Often there are local support groups for families whose children have a variety of special needs. There are also several internet-based support groups, some of whose members have 1p36 deletion syndrome.


Other support groups and related websites can be found at…


1p36 Deletion Support & Awareness (1P36 DSA)

Support, Awareness & Education to improve the lives of individuals affected by 1p36 Deletion Syndrome



Beccas Foundation



GeneReviews - Disease Characteristics



Chromosome Deletion Outreach



Unique-Rare Chromosome Disorder Support Group



Mothers United for Moral Support (MUMS)



National Organization for Rare Disorders



OMIM, Online Mendelian Inheritance in Man




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