Disease Profile

8q12 microduplication syndrome

Prevalence ?
Prevalence estimates on Rare Medical Network websites are calculated based on data available from numerous sources, including US and European government statistics, the NIH, Orphanet, and published epidemiologic studies. Rare disease population data is recognized to be highly variable, and based on a wide variety of source data and methodologies, so the prevalence data on this site should be assumed to be estimated and cannot be considered to be absolutely correct.
<1 / 1 000 000

< 331

US Estimated

< 514

Europe Estimated

Age of Onset






Autosomal dominant ?A pathogenic variant in only one gene copy in each cell is sufficient to cause an autosomal dominant disease


Autosomal recessive ?Pathogenic variants in both copies of each gene of the chromosome are needed to cause an autosomal recessive disease and observe the mutant phenotype


X-linked dominant ?X-linked dominant inheritance, sometimes referred to as X-linked dominance, is a mode of genetic inheritance by which a dominant gene is carried on the X chromosome.


X-linked recessive ?Pathogenic variants in both copies of a gene on the X chromosome cause an X-linked recessive disorder


Mitochondrial or multigenic ?Mitochondrial genetic disorders can be caused by changes (mutations) in either the mitochondrial DNA or nuclear DNA that lead to dysfunction of the mitochondria and inadequate production of energy.


Multigenic or multifactor ?Inheritance involving many factors, of which at least one is genetic but none is of overwhelming importance, as in the causation of a disease by multiple genetic and environmental factors.


Not applicable


Other Names (AKA)

Dup(8)(q12); Trisomy 8q12; Chromosome 8q12 microduplication syndrome


Congenital and Genetic Diseases


The following summary is from Orphanet, a European reference portal for information on rare diseases and orphan drugs.

Orpha Number: 228399

The newly described 8q12 microduplication syndrome is associated with unusual and characteristic multiorgan clinical features, which include hearing loss, congenital heart defects, intellectual disability, hypotonia in infancy, and Duane anomaly (see this term).

It has been described in two patients.

Clinical description
The mild facial dysmorphism is characterized by high, arched eyebrows and unilateral narrowing of the palpebral fissure and retraction of the globe caused by Duane anomaly (Duane anomaly is a form of complex strabismus characterized by limited ocular abduction and variably limited adduction accompanied by retraction of the globe, which narrows the palpebral fissure).

This microduplication was identified by microarray-based comparative genomic hybridization (aCGH). The lack of recurrent breakpoints in these two cases and the absence of any low-copy repeats (LCR) pairs that flank these de novo events do not support non-allelic homologous recombination as the mutation mechanism. The 8q12 region includes CHD7 and it is proposed that this gene, associated with CHARGE syndrome by haploinsufficiency, causes a different phenotype by gain-of-dosage.

Visit the Orphanet disease page for more resources.


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.

Medical Terms Other Names
Learn More:
80%-99% of people have these symptoms
Duane anomaly
Global developmental delay
Long palpebral fissure
Broad opening between the eyelids
Long opening between the eyelids
Wide opening between the eyelids

[ more ]

Muscular hypotonia
Low or weak muscle tone
Sensorineural hearing impairment
Ventricular septal defect
Hole in heart wall separating two lower heart chambers
30%-79% of people have these symptoms
Abnormal cranial nerve morphology
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 ]

Attention deficit hyperactivity disorder
Attention deficit
Attention deficit disorder
Attention deficit-hyperactivity disorder
Attention deficits
Childhood attention deficit/hyperactivity disorder

[ more ]

Short and broad skull
Eye folds
Prominent eye folds

[ more ]

Everted lower lip vermilion
Drooping lower lip
Outward turned lower lip

[ more ]

Gastroesophageal reflux
Acid reflux
Acid reflux disease

[ more ]

Highly arched eyebrow
Arched eyebrows
Broad, arched eyebrows
High, rounded eyebrows
High-arched eyebrows
Thick, flared eyebrows

[ more ]

Long philtrum
Narrow mouth
Small mouth
Short foot
Short feet
Small feet

[ more ]

Corners of eye widely separated
Vesicoureteral reflux
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 ]


Learn More

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.

In-Depth Information

  • 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.
  • Orphanet is a European reference portal for information on rare diseases and orphan drugs. Access to this database is free of charge.