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

Proximal chromosome 18q deletion syndrome


Other Names:
Proximal 18q deletion syndrome; Proximal 18q-; Monosomy 18q syndrome; Proximal 18q deletion syndrome; Proximal 18q-; Monosomy 18q syndrome; Proximal 18q deletion See More
Categories:
This disease is grouped under:
Chromosome 18q deletion
Proximal chromosome 18q deletion syndrome is a chromosome abnormality that occurs when there is a missing (deleted) copy of genetic material from the part of the long (q) arm near the center 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 proximal chromosome 18q deletion syndrome include developmental delay, intellectual disability, and distinctive facial features. The might also have seizures, low muscle tone (hypotonia), speech and language delays, obesity, and short stature.[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 a 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 proximal 18q 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 FAQs About Chromosome Disorders.

Last updated: 9/20/2016

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.

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Medical Terms Other Names
Learn More:
HPO ID
30%-79% of people have these symptoms
Abnormal facial shape
Unusual facial appearance
0001999
Abnormal myelination 0012447
Abnormal palmar dermatoglyphics 0001018
Abnormal retinal morphology
Retina issue
0000479
Arachnodactyly
Long slender fingers
Spider fingers
[ more ] 		0001166
Bilateral conductive hearing impairment 0008513
Bilateral cryptorchidism 0008689
Delayed skeletal maturation
Delayed bone maturation
Delayed skeletal development
[ more ] 		0002750
Depressed nasal bridge
Depressed bridge of nose
Flat bridge of nose
Flat nasal bridge
Flat, nasal bridge
Flattened nasal bridge
Low nasal bridge
Low nasal root
[ more ] 		0005280
Diffuse white matter abnormalities 0007204
Downturned corners of mouth
Downturned corners of the mouth
Downturned mouth
[ more ] 		0002714
Global developmental delay 0001263
Intellectual disability, mild
Mental retardation, borderline-mild
Mild and nonprogressive mental retardation
Mild mental retardation
[ more ] 		0001256
Kyphoscoliosis 0002751
Macrotia
Large ears
0000400
Mandibular prognathia
Big lower jaw
Increased projection of lower jaw
Increased size of lower jaw
Large lower jaw
Prominent chin
Prominent lower jaw
[ more ] 		0000303
Micropenis
Short penis
Small penis
[ more ] 		0000054
Myopia
Close sighted
Near sighted
Near sightedness
Nearsightedness
[ more ] 		0000545
Neonatal hypotonia
Low muscle tone, in neonatal onset
0001319
Patent ductus arteriosus 0001643
Pes planus
Flat feet
Flat foot
[ more ] 		0001763
Poor coordination 0002370
Pulmonary valve defects 0005148
Secondary growth hormone deficiency 0008240
Short stature
Decreased body height
Small stature
[ more ] 		0004322
Talipes equinovarus
Club feet
Club foot
Clubfeet
Clubfoot
[ more ] 		0001762
Tapered finger
Tapered fingertips
Tapering fingers
[ more ] 		0001182
5%-29% of people have these symptoms
Absence of the pulmonary valve 0005134
Aortic aneurysm
Bulge in wall of large artery that carries blood away from heart
0004942
Aortic valve stenosis
Narrowing of aortic valve
0001650
Biparietal narrowing 0004422
Bulbous nose 0000414
Cerebellar hypoplasia
Small cerebellum
Underdeveloped cerebellum
[ more ] 		0001321
Choanal stenosis
Narrowing of the rear opening of the nasal cavity
0000452
Choreoathetosis 0001266
Congestive heart failure
Cardiac failure
Cardiac failures
Heart failure
[ more ] 		0001635
Decreased circulating IgA level 0002720
Downslanted palpebral fissures
Downward slanting of the opening between the eyelids
0000494
Dysplastic pulmonary valve 0005164
Epicanthus
Eye folds
Prominent eye folds
[ more ] 		0000286
Failure to thrive
Faltering weight
Weight faltering
[ more ] 		0001508
High palate
Elevated palate
Increased palatal height
[ more ] 		0000218
Hydrocephalus
Too much cerebrospinal fluid in the brain
0000238
Hypothyroidism
Underactive thyroid
0000821
Joint hypermobility
Double-Jointed
Flexible joints
Increased mobility of joints
[ more ] 		0001382
Left aortic arch with right descending aorta and right ductus arteriosus 0011596
Left-to-right shunt 0012382
Low anterior hairline
Low frontal hairline
Low-set frontal hairline
[ more ] 		0000294
Microcephaly
Abnormally small skull
Decreased circumference of cranium
Decreased size of skull
Reduced head circumference
Small head circumference
[ more ] 		0000252
Mitral regurgitation 0001653
Open mouth
Gaped jawed appearance
Gaped mouthed appearance
Slack jawed appearance
[ more ] 		0000194
Pectus excavatum
Funnel chest
0000767
Prominent nose
Big nose
Disproportionately large nose
Increased nasal size
Increased size of nose
Large nose
Pronounced nose
[ more ] 		0000448
Secundum atrial septal defect 0001684
Seizure 0001250
Sensorineural hearing impairment 0000407
Short philtrum 0000322
Slender build
Thin build
0001533
Strabismus
Cross-eyed
Squint
Squint eyes
[ more ] 		0000486
Thick vermilion border
Full lips
Increased volume of lip
Plump lips
Prominent lips
Thick lips
[ more ] 		0012471
Wide mouth
Broad mouth
Large mouth
[ more ] 		0000154
1%-4% of people have these symptoms
Astrocytoma 0009592
Atlantoaxial abnormality 0003413
Percent of people who have these symptoms is not available through HPO
Abnormality of the cerebral white matter 0002500
Ascending tubular aorta aneurysm
Bulging of wall of large artery located above heart
0004970
Asthma 0002099
Atopic dermatitis 0001047
Atresia of the external auditory canal
Absent ear canal
0000413
Atrial septal defect
An opening in the wall separating the top two chambers of the heart
Hole in heart wall separating two upper heart chambers
[ more ] 		0001631
Autosomal dominant inheritance 0000006
Bifid uvula 0000193
Blepharophimosis
Narrow opening between the eyelids
0000581
Broad-based gait
Wide based walk
0002136
Chorea 0002072
Cleft upper lip
Harelip
0000204
Conductive hearing impairment
Conductive deafness
Conductive hearing loss
[ more ] 		0000405
Cryptorchidism
Undescended testes
Undescended testis
[ more ] 		0000028
Delayed CNS myelination 0002188
Dysplastic aortic valve 0005176
Failure to thrive in infancy
Faltering weight in infancy
Weight faltering in infancy
[ more ] 		0001531
Generalized hypotonia
Decreased muscle tone
Low muscle tone
[ more ] 		0001290
Growth hormone deficiency 0000824
Hypertelorism
Wide-set eyes
Widely spaced eyes
[ more ] 		0000316
Hypospadias 0000047
Inguinal hernia 0000023
Intellectual disability
Mental deficiency
Mental retardation
Mental retardation, nonspecific
Mental-retardation
[ more ] 		0001249
Joint laxity
Joint instability
Lax joints
Loose-jointedness
Loosejointedness
[ more ] 		0001388
Malar flattening
Zygomatic flattening
0000272
Midface retrusion
Decreased size of midface
Midface deficiency
Underdevelopment of midface
[ more ] 		0011800
Motor delay 0001270
Muscular hypotonia
Low or weak muscle tone
0001252
Nystagmus
Involuntary, rapid, rhythmic eye movements
0000639
Optic atrophy 0000648
Overlapping toe
Overlapping toes
Overriding toes
[ more ] 		0001845
Pes cavus
High-arched foot
0001761
Proximal placement of thumb
Attachment of thumb close to wrist
0009623
Recurrent respiratory infections
Frequent respiratory infections
Multiple respiratory infections
respiratory infections, recurrent
Susceptibility to respiratory infections
[ more ] 		0002205
Rocker bottom foot
Rocker bottom feet
Rocker-bottom feet
Rockerbottom feet
[ more ] 		0001838
Rod-cone dystrophy 0000510
Scoliosis 0002650
Secretory IgA deficiency 0004433
Short neck
Decreased length of neck
0000470
Short palpebral fissure
Short opening between the eyelids
0012745
Sporadic
No previous family history
0003745
Stenosis of the external auditory canal
Narrowing of passageway from outer ear to middle ear
0000402
Toe syndactyly
Fused toes
Webbed toes
[ more ] 		0001770
Tremor 0001337
Umbilical hernia 0001537
U-Shaped upper lip vermilion
Carp-like mouth
Carp-shaped mouth
Fish mouth
Large, carp-shaped mouth
Wide, carp-shaped mouth
[ more ] 		0010806
Ventricular septal defect
Hole in heart wall separating two lower heart chambers
0001629
Ventriculomegaly 0002119
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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

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 Proximal chromosome 18q deletion syndrome. 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 Proximal chromosome 18q deletion syndrome:
    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 Proximal chromosome 18q deletion syndrome. 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.
  • The Chromosome 18 Registry & Research Society is an advocacy organization composed of parents of individuals with chromosome 18 abnormalities. Click on the link above to view their information page on proximal 18q deletion syndrome.

In-Depth Information

  • The Chromosome 18 Clinical Research Center provides clinical management guidelines for people with different disorders involving chromosome 18, including Proximal chromosome 18q deletion syndrome.
  • 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 Proximal chromosome 18q deletion syndrome. 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. Submit a new question

  • Is it possible to potty train my daughter who has proximal chromosome 18q deletion syndrome? See answer


  1. 18q deletion syndrome. Genetics Home Reference (GHR). June 2014; https://ghr.nlm.nih.gov/condition/18q-deletion-syndrome.
  2. Proximal 18q-. The Chromosome 18 Registry and Research Society. December 9, 2015; http://www.chromosome18.org/18q/proximal-18q/.
  3. Fryns JP, Hulten M. 18q deletions from 18q11.2 to 18q21.2. Unique. February 2, 2014; http://www.rarechromo.org/information/Chromosome%2018/18q%20deletions%20from%20%2018q11.2%20to%2018q21.2%20FTNP.pdf.