Marcus Gunn phenomenon

Is Marcus Gunn phenomenon inherited?

People with Marcus Gunn phenomenon usually have no family history of the disorder and do not pass it down to their children. However there have been reported cases where more than one family member has the disorder, but so far the genetic cause in these families is unknown. Sometimes, people with Marcus Gunn phenomenon are also born with other birth defects. In these cases, a chromosome or gene mutation may be found.

Since there are different causes of Marcus Gunn phenomenon and in most cases the cause is unknown, it is difficult to predict if it can be passed down in a family. If a gene or chromosome mutation is found, the risk of passing the Marcus Gunn phenomenon down to children will depend on the mutation.

Last updated on 05-01-20

How might Marcus Gunn phenomenon be treated?

While it may not be needed in every case, people with Marcus Gunn phenomenon may benefit from surgery. Children with Marcus Gunn phenomenon need to be regularly monitored for amblyopia. If not addressed by age 7 to 10 years of age, amblyopia may become untreatable. Untreated severe ptosis can also result in vision loss. Other associated eye problems, such as horizontal strabismus, vertical strabismus, and double elevator palsy typically need to be addressed before considering how to manage Marcus Gunn phenomenon itself. These related eye problems may be corrected with eyeglasses, surgery, and/or medications.

Surgery for Marcus Gunn phenomenon may be considered for ptosis or jaw winking that is considered cosmetically significant, or causing amblyopia. Depending on the degree of ptosis and severity of jaw winking, several surgical techniques have been proposed. For mild Marcus Gunn phenomenon, management has included observation, levator muscle resection, and the Fasanella-Servat procedure.

More detailed information about treatment of Marcus Gunn phenomenon is available on Medscape Reference's Web site and can be viewed here.

Last updated on 05-01-20

In-Depth Information


EyeWiki is an eye encyclopedia written by eye physicians and surgeons that offers an information page on Marcus Gunn phenomenon. Please click the link to access this resource.

Last updated on 04-27-20

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