What are the other Names for this Condition? (Also known as/Synonyms)

• Duane Retraction Syndrome 1
• DURS1 (Duane Retraction Syndrome 1)

What is Duane Syndrome Type 1? (Definition/Background Information)

• Duane Syndrome Type 1 is the most common type of Duane syndrome, an eye movement disorder that is present at birth
• People with Duane Syndrome have restricted ability to move the affected eye(s) outward toward the ear (abduction) and/or inward toward the nose (adduction). The different types are distinguished by the eye movements that are most restricted
• Duane Syndrome Type 1 is characterized by absent to very restricted abduction and normal to mildly restricted adduction
• The eye opening (palpebral fissure) narrows and the eyeball retracts into the orbit with adduction. With abduction, the reverse occurs
• One or both eyes may be affected. The majority of cases are sporadic (not inherited), while about 10% are familial. 70% of affected people do not have any other abnormalities at birth (isolated Duane syndrome)
• Treatment is mainly supportive and may include glasses or contact lenses for vision correction, eye patches, or surgery

(Source: Duane Syndrome Type 1; Genetic and Rare Diseases Information Center (GARD) of National Center for Advancing Translational Sciences (NCATS), USA.)

Who gets Duane Syndrome Type 1? (Age and Sex Distribution)

• Duane Syndrome Type 1 is a rare congenital disorder. The presentation of symptoms may occur in childhood
• Both males and females may be affected
• Worldwide, individuals of all racial and ethnic groups may be affected

What are the Risk Factors for Duane Syndrome Type 1? (Predisposing Factors)

• A positive family history may be an important risk factor, since Duane Syndrome Type 1 is an inherited condition
• Currently, no risk factors have been clearly identified for the disorder

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases one’s chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Duane Syndrome Type 1? (Etiology)

• The exact genetic cause of Duane Syndrome Type 1 is not known. However, the causative gene(s) map to the long arm (q) of chromosome 8
• Duane Syndrome Type 1 is inherited in an autosomal dominant manner

Autosomal dominant inheritance: Autosomal dominant conditions are traits or disorders that are present when only one copy of the mutation is inherited on a non-sex chromosome. In these types of conditions, the individual has one normal copy and one mutant copy of the gene. The abnormal gene dominates, masking the effects of the correctly function gene. If an individual has an autosomal dominant condition, the chance of passing the abnormal gene on to their offspring is 50%. Children, who do not inherit the abnormal gene, will not develop the condition or pass it on to their offspring.

What are the Signs and Symptoms of Duane Syndrome Type 1?

The signs and symptoms of Duane Syndrome Type 1 may include:

Very frequently present symptoms in 80-99% of the cases:

• Oculomotor nerve palsy 
• Short palpebral fissure
• Strabismus

Frequently present symptoms in 30-79% of the cases:

• Abnormal vertebral segmentation and fusion 
• Anteverted nares
• Blepharophimosis
• Deeply set eye
• Low posterior hairline
• Sensorineural hearing impairment

Occasionally present symptoms in 5-29% of the cases:

• Abnormal form of the vertebral bodies 
• Abnormality of cardiovascular system morphology         
• Abnormality of the pupil
• Absent radius     
• Amblyopia
• Aniridia
• Anorectal anomaly          
• Aplasia/Hypoplasia of the thumb
• Blepharospasm
• Brachydactyly 
• Camptodactyly 
• Central heterochromia                   
• Chorioretinal coloboma 
• Cleft palate 
• Ectopic kidney
• Everted lower lip vermilion
• External ear malformation 
• Facial asymmetry
• Global developmental delay       
• Hypopigmented skin patches 
• Hypoplasia of the radius 
• Hypoplastic iris stroma 
• Iris coloboma
• Irregular hyperpigmentation 
• Microcephaly
• Microcornea 
• Micrognathia
• Narrow internal auditory canal 
• Nystagmus 
• Optic disc hypoplasia 
• Patchy hypopigmentation of hair 
• Plagiocephaly
• Preauricular skin tag 
• Preaxial hand polydactyly
• Ptosis
• Seizures
• Short neck
• Skeletal muscle atrophy
• Spina bifida occulta 
• Stenosis of the external auditory canal 
• Talipes equinovarus
• Triphalangeal thumb
• Webbed neck
• Wide nasal bridge

In addition, the following signs and symptoms may also be present:

• Congenital strabismus
• Duane anomaly 
• Impaired convergence 
• Impaired ocular abduction 
• Impaired ocular adduction 
• Palpebral fissure narrowing on adduction

(Source: Duane Syndrome Type 1; Genetic and Rare Diseases Information Center (GARD) of National Center for Advancing Translational Sciences (NCATS), USA.)

How is Duane Syndrome Type 1 Diagnosed?

Duane Syndrome Type 1 is diagnosed on the basis of the following information:

• Complete physical examination
• Thorough medical history evaluation
• Assessment of signs and symptoms
• Laboratory tests
• Imaging studies
• Biopsy studies, if necessary

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Duane Syndrome Type 1?

The complications of Duane Syndrome Type 1 may include:

• Impaired vision
• Hearing loss

Complications may occur with or without treatment, and in some cases, due to treatment also.

How is Duane Syndrome Type 1 Treated?

There is no cure for Duane Syndrome Type 1. The treatment options may include:

• Correction of amblyopia ("lazy eye")
• Wearing glasses or contact lenses
• The use of prisms to correct for abnormal head posture
• Possible eye muscle surgery

(Source: Duane Syndrome Type 1; Genetic and Rare Diseases Information Center (GARD) of National Center for Advancing Translational Sciences (NCATS), USA.)

How can Duane Syndrome Type 1 be Prevented?

Duane Syndrome Type 1 may not be preventable, since it is a genetic disorder.

• If there is a family history of the condition, then genetic counseling will help assess risks, before planning for a child
• Active research is currently being performed to explore the possibilities for treatment and prevention of inherited and acquired genetic disorders
• Regular medical screening at periodic intervals with tests and physical examinations are recommended

What is the Prognosis of Duane Syndrome Type 1? (Outcomes/Resolutions) 

• The prognosis of Duane Syndrome Type 1 is dependent upon the severity of the signs and symptoms and associated complications, if any
• Individuals with mild conditions have better prognosis than those with severe symptoms and complications
• Typically, the prognosis may be assessed on a case-by-case basis

Additional and Relevant Useful Information for Duane Syndrome Type 1:

The following DoveMed website link is a useful resource for additional information:

http://www.dovemed.com/diseases-conditions/rare-disorders/