National Center for Advancing and Translational Sciences Genetic and Rare Diseases Information Center, a program of the National Center for Advancing and Translational Sciences

Chromosome 18p deletion


Other Names:
18p-; Monosomy 18p
Categories:
Chromosome 18p deletion is a chromosome abnormality that occurs when there is a missing (deleted) copy of genetic material on the short arm (p) of chromosome 18. The severity of the condition and the signs and symptoms depend on the size and location of the deletion and which genes are involved. Features that often occur in people with chromosome 18p deletion include developmental delay, intellectual disability, behavioral problems and distinctive facial features.[1][2][3] Chromosome testing of both parents can provide more information on whether or not the deletion was inherited. In most cases, parents do not have any chromosomal anomaly. However, sometimes one parent is found to have a balanced translocation, where a piece of a chromosome has broken off and attached to another one with no gain or loss of genetic material. The balanced translocation normally does not cause any signs or symptoms, but it increases the risk for having an affected child with a chromosomal anomaly like a deletion. Treatment is based on the signs and symptoms present in each person.

This page is meant to provide general information about 18p deletions. You can contact GARD if you have questions about a specific deletion on chromosome 18. To learn more about chromosomal anomalies please visit our GARD webpage on FAQs about Chromosome Disorders.
Last updated: 4/11/2018

This table lists symptoms that people with this disease may have. For most diseases, symptoms will vary from person to person. People with the same disease may not have all the symptoms listed. This information comes from a database called the Human Phenotype Ontology (HPO) . The HPO collects information on symptoms that have been described in medical resources. The HPO is updated regularly. Use the HPO ID to access more in-depth information about a symptom.

Showing of 53 |
Medical Terms Other Names
Learn More:
HPO ID
80%-99% of people have these symptoms
Abnormality of the antihelix 0009738
Brachydactyly
Short fingers or toes
0001156
Delayed speech and language development
Deficiency of speech development
Delayed language development
Delayed speech
Delayed speech acquisition
Delayed speech development
Impaired speech and language development
Impaired speech development
Language delay
Language delayed
Language development deficit
Late-onset speech development
Poor language development
Speech and language delay
Speech and language difficulties
Speech delay
[ more ] 		0000750
Global developmental delay 0001263
Hypodontia
Failure of development of between one and six teeth
0000668
Intellectual disability
Mental deficiency
Mental retardation
Mental retardation, nonspecific
Mental-retardation
[ more ] 		0001249
Protruding ear
Prominent ear
Prominent ears
[ more ] 		0000411
Short philtrum 0000322
Short stature
Decreased body height
Small stature
[ more ] 		0004322
30%-79% of people have these symptoms
Brachycephaly
Short and broad skull
0000248
Carious teeth
Dental cavities
Tooth cavities
Tooth decay
[ more ] 		0000670
Cleft palate
Cleft roof of mouth
0000175
Downturned corners of mouth
Downturned corners of the mouth
Downturned mouth
[ more ] 		0002714
Enlarged thorax
Wide rib cage
0100625
Epicanthus
Eye folds
Prominent eye folds
[ more ] 		0000286
Hypertension 0000822
Kyphoscoliosis 0002751
Low posterior hairline
Low hairline at back of neck
0002162
Macrotia
Large ears
0000400
Microcephaly
Abnormally small skull
Decreased circumference of cranium
Decreased size of skull
Reduced head circumference
Small head circumference
[ more ] 		0000252
Micrognathia
Little lower jaw
Small jaw
Small lower jaw
[ more ] 		0000347
Misalignment of teeth
Abnormal dental position
Abnormal teeth spacing
Abnormality of alignment of teeth
Abnormality of teeth spacing
Crooked teeth
Malaligned teeth
Malposition of teeth
Malpositioned teeth
[ more ] 		0000692
Muscular hypotonia
Low or weak muscle tone
0001252
Pectus excavatum
Funnel chest
0000767
Ptosis
Drooping upper eyelid
0000508
Short neck
Decreased length of neck
0000470
Webbed neck
Neck webbing
0000465
Wide intermamillary distance
Wide-spaced nipples
Widely spaced nipples
Widely-spaced nipples
[ more ] 		0006610
Wide nasal bridge
Broad nasal bridge
Broad nasal root
Broadened nasal bridge
Increased breadth of bridge of nose
Increased breadth of nasal bridge
Increased width of bridge of nose
Increased width of nasal bridge
Nasal bridge broad
Wide bridge of nose
Widened nasal bridge
[ more ] 		0000431
5%-29% of people have these symptoms
Abnormality of cardiovascular system morphology 0030680
Alopecia
Hair loss
0001596
Autoimmunity
Autoimmune disease
Autoimmune disorder
[ more ] 		0002960
Behavioral abnormality
Behavioral changes
Behavioral disorders
Behavioral disturbances
Behavioral problems
Behavioral/psychiatric abnormalities
Behavioural/Psychiatric abnormality
Psychiatric disorders
Psychiatric disturbances
[ more ] 		0000708
Generalized dystonia 0007325
Holoprosencephaly 0001360
Hypothyroidism
Underactive thyroid
0000821
Lymphedema
Swelling caused by excess lymph fluid under skin
0001004
Microphthalmia
Abnormally small eyeball
0000568
Percent of people who have these symptoms is not available through HPO
Anteverted nares
Nasal tip, upturned
Upturned nasal tip
Upturned nose
Upturned nostrils
[ more ] 		0000463
Autosomal dominant inheritance 0000006
Clinodactyly
Permanent curving of the finger
0030084
Cryptorchidism
Undescended testes
Undescended testis
[ more ] 		0000028
Decreased testicular size
Small testes
Small testis
[ more ] 		0008734
Dystonia 0001332
Gonadal dysgenesis 0000133
High palate
Elevated palate
Increased palatal height
[ more ] 		0000218
Hypertelorism
Wide-set eyes
Widely spaced eyes
[ more ] 		0000316
Micropenis
Short penis
Small penis
[ more ] 		0000054
Radial deviation of finger 0009466
Redundant neck skin
Excess neck skin
Excess skin over the neck
Redundant skin folds of neck
Redundant skin over the neck
[ more ] 		0005989
Round face
Circular face
Round facial appearance
Round facial shape
[ more ] 		0000311
Small for gestational age
Birth weight less than 10th percentile
Low birth weight
[ more ] 		0001518
Sporadic
No previous family history
0003745
Showing of 53 |
Last updated: 7/1/2020

If you need medical advice, you can look for doctors or other healthcare professionals who have experience with this disease. You may find these specialists through advocacy organizations, clinical trials, or articles published in medical journals. You may also want to contact a university or tertiary medical center in your area, because these centers tend to see more complex cases and have the latest technology and treatments.

If you can’t find a specialist in your local area, try contacting national or international specialists. They may be able to refer you to someone they know through conferences or research efforts. Some specialists may be willing to consult with you or your local doctors over the phone or by email if you can't travel to them for care.

You can find more tips in our guide, How to Find a Disease Specialist. We also encourage you to explore the rest of this page to find resources that can help you find specialists.

Healthcare Resources

Related diseases are conditions that have similar signs and symptoms. A health care provider may consider these conditions in the table below when making a diagnosis. Please note that the table may not include all the possible conditions related to this disease.

Conditions with similar signs and symptoms from Orphanet
Differential diagnosis may include a wide number of syndromes with short stature and mild intellectual deficiency. In young children, deletion 18p syndrome may be vaguely evocative of either Turner syndrome or trisomy 21 (see these terms).
Visit the Orphanet disease page for more information.

Research helps us better understand diseases and can lead to advances in diagnosis and treatment. This section provides resources to help you learn about medical research and ways to get involved.

Patient Registry

  • A registry supports research by collecting of information about patients that share something in common, such as being diagnosed with Chromosome 18p deletion. The type of data collected can vary from registry to registry and is based on the goals and purpose of that registry. Some registries collect contact information while others collect more detailed medical information. Learn more about registries.

    Registries for Chromosome 18p deletion:
    Chromosome 18 Registry & Research Society
     

Support and advocacy groups can help you connect with other patients and families, and they can provide valuable services. Many develop patient-centered information and are the driving force behind research for better treatments and possible cures. They can direct you to research, resources, and services. Many organizations also have experts who serve as medical advisors or provide lists of doctors/clinics. Visit the group’s website or contact them to learn about the services they offer. Inclusion on this list is not an endorsement by GARD.

Organizations Supporting this Disease

These resources provide more information about this condition or associated symptoms. The in-depth resources contain medical and scientific language that may be hard to understand. You may want to review these resources with a medical professional.

Where to Start

  • Genetics Home Reference (GHR) contains information on Chromosome 18p deletion. This website is maintained by the National Library of Medicine.
  • The National Organization for Rare Disorders (NORD) has a report for patients and families about this condition. NORD is a patient advocacy organization for individuals with rare diseases and the organizations that serve them.
  • Unique is a source of information and support to families and individuals affected by rare chromosome disorders. Click on the link to view information about 18p deletions.

In-Depth Information

  • The Chromosome 18 Clinical Research Center provides clinical management guidelines for people with different disorders involving chromosome 18, including Chromosome 18p deletion.
  • The Monarch Initiative brings together data about this condition from humans and other species to help physicians and biomedical researchers. Monarch’s tools are designed to make it easier to compare the signs and symptoms (phenotypes) of different diseases and discover common features. This initiative is a collaboration between several academic institutions across the world and is funded by the National Institutes of Health. Visit the website to explore the biology of this condition.
  • Online Mendelian Inheritance in Man (OMIM) is a catalog of human genes and genetic disorders. Each entry has a summary of related medical articles. It is meant for health care professionals and researchers. OMIM is maintained by Johns Hopkins University School of Medicine. 
  • Orphanet is a European reference portal for information on rare diseases and orphan drugs. Access to this database is free of charge.
  • PubMed is a searchable database of medical literature and lists journal articles that discuss Chromosome 18p deletion. Click on the link to view a sample search on this topic.

Questions sent to GARD may be posted here if the information could be helpful to others. We remove all identifying information when posting a question to protect your privacy. If you do not want your question posted, please let us know.

  1. 18p deletions. Unique. 2013; http://www.rarechromo.org/information/Chromosome%2018/18p%20deletions%20FTNW.pdf.
  2. 18p-. The Chromosome 18 Registry and Research Society. December 2015; http://www.chromosome18.org/18p/.
  3. Chromosome 18, Monosomy 18p. NORD. 2009; http://rarediseases.org/rare-diseases/chromosome-18-monosomy-18p/.