Última actualización:
March 24, 2008
Años publicados: 1991, 1997, 2003
Marcus Gunn phenomenon is a rare genetic disorder that is usually present at birth. It is characterized by the movement of one upper eyelid in a rapid rising motion each time the jaw moves. Other eye abnormalities and vision difficulties may also occur. The exact cause of this phenomenon is not known.
In most patients with Marcus Gunn phenomenon, the upper eyelid of one eye (unilateral) droops (blepharoptosis). The major symptom of this disorder is the rapid and involuntary upward movement of the affected eyelid after almost any movement of the lower jaw. As a result, that eye appears to open even wider. This first becomes apparent soon after birth, especially during feeding and sucking. These activities cause the eyelid to move up and down. A few cases have been seen in adults.
Individuals with Marcus Gunn phenomenon may experience visual impairment, such as crossing of the eyes (strabismus), slight impairment of vision in one eye as compared to the other (a difference in the refractive powers of the eyes [anisometropia], and other problems (e.g., superior rectus muscle palsy or double elevator palsy).
In some cases, symptoms may be produced by movement of the lips, whistling, smiling, clenching the teeth, chewing, puffing out the cheeks, or swallowing.
The exact cause of Marcus Gunn phenomenon is not known. For reasons that are unclear, there is a bad connection between the nerves that stimulate, and the muscles that move, the eyelids and the jaw. Some clinical researchers believe that about half of the cases of Marcus Gunn phenomenon are genetically determined. The site and nature of the gene(s) at fault in this disorder are not known, but familial studies indicate that it is transmitted as an autosomal dominant trait.
Chromosomes, which are present in the nucleus of human cells, carry the genetic information for each individual. Human body cells normally have 46 chromosomes. Pairs of human chromosomes are numbered from 1 through 22 and the sex chromosomes are designated X and Y. Males have one X and one Y chromosome and females have two X chromosomes. Each chromosome has a short arm designated p and a long arm designated q. Chromosomes are further sub-divided into many bands that are numbered. For example, chromosome 11p13 refers to band 13 on the short arm of chromosome 11. The numbered bands specify the location of the thousands of genes that are present on each chromosome.
Genetic diseases are determined by the combination of genes for a particular trait which are on the chromosomes received from the father and the mother.
Dominant genetic disorders occur when only a single copy of an abnormal gene is necessary for the appearance of the disease. The abnormal gene can be inherited from either parent, or can be the result of a new mutation (gene change) in the affected individual. The risk of passing the abnormal gene from affected parent to offspring is 50% for each pregnancy regardless of the sex of the resulting child.
Marcus Gunn phenomenon is a rare genetic disorder present at birth. It affects males and females in equal numbers. Approximately 300 cases have been reported in the medical literature.
The diagnosis is obvious and is often made by one or both of the parents who become aware of the major symptom during feeding.
Treatment
Treatment of Marcus Gunn phenomenon is usually not needed because the condition tends to grow less noticeable with age. Genetic counseling may be of benefit for patients and their families. Other related eye problems such as strabismus, amblyopia, etc., may be corrected with eyeglasses, surgery and/or drugs.
Surgical correction of the droopiness of the eyelid or of the jaw winking is recommended only if the patient (or parents) agree on which of the symptoms is the more cosmetically objectionable. Surgical procedures are available for several different intensities of the droop of the eyelids.
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TEXTBOOKS
Gorlin RJ, Cohen MMJr, Levin LS. Eds. Syndromes of the Head and Neck. 3rd ed. Oxford University Press, London, UK; 1990:604-05.
Kanski JJ. Ed. Clinical Ophthalmology. 4th ed. Butterworth-Heinemann. Oxford, UK; 1999:35.
Newell FW. Ed. Ophthalmology: Principles and Concepts. 7th ed. Mosby Year Book, St. Louis, MO; 1991:168.
JOURNAL ARTICLES
Wong JF, Theriault JF, Bouzouaya C, et al. Marcus-Gun jaw-winking phenomenon: a new supplemental test in the preoperative evaluation. Ophthal Plastic Reconstr Surg. 2001;17:412-18.
Hwang JM, Park SH. A case of Marcus Gunn jaw winking and pseudo inferior oblique overaction. Am J Ophthalmol. 2001;131:148-50.
Kodsi S. Marcu Gunn jaw winking with trigemino-abducens synkinesis. J AAPOS. 2000;4:316-17.
Yoshikata R, Yanai A. A clinical sign of the Marcus Gunn phenomenon. Case Report. Scand J Plastic Reconstr Surg Hand Surg. 1999;33:237-41.
Bartkowski SB, Zapala J, Wyszynska-Pawelec G, et al. Marcus Gunn Jaw-Winking Phenomenon: management and results of treatment in 19 patients. J Craniomaxillofac Surg. 1999;27:25-29.
Landau WM. Clinical Neuromythology. I. The Marcus Gunn phenomenon: loose canon of neuroophthalmology. Neurology. 1988;38:1141-42.
FROM THE INTERNET
McKusick VA, Ed. Online Mendelian Inheritance In Man (OMIM). Marcus Gunn Phenomenon. The Johns Hopkins University. Entry Number;154600: Last Edit Date; 11/6/1994.
Blaydon SM. Marcus Gunn Jaw-winking Syndrome. emedicine. Last Updated: July 6, 2001. 11pp.
www.emedicine.com/iph/topic608.htm
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Aprende más https://rarediseases.org/patient-assistance-programs/caregiver-respite/The information provided on this page is for informational purposes only. The National Organization for Rare Disorders (NORD) does not endorse the information presented. The content has been gathered in partnership with the MONDO Disease Ontology. Please consult with a healthcare professional for medical advice and treatment.
The Genetic and Rare Diseases Information Center (GARD) has information and resources for patients, caregivers, and families that may be helpful before and after diagnosis of this condition. GARD is a program of the National Center for Advancing Translational Sciences (NCATS), part of the National Institutes of Health (NIH).
View reportOrphanet has a summary about this condition that may include information on the diagnosis, care, and treatment as well as other resources. Some of the information and resources are available in languages other than English. The summary may include medical terms, so we encourage you to share and discuss this information with your doctor. Orphanet is the French National Institute for Health and Medical Research and the Health Programme of the European Union.
View reportOnline Mendelian Inheritance In Man (OMIM) has a summary of published research about this condition and includes references from the medical literature. The summary contains medical and scientific terms, so we encourage you to share and discuss this information with your doctor. OMIM is authored and edited at the McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine.
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