Title : Marcus gunn syndrome: A Case Report
Abstract:
A Case ReportIntroduction Marcus Gunn syndrome is a rare genetic condition that combines congenital neurogenic ptosis with mandibulopalpebral synkinesis. This synkinesis involves the involuntary elevation of the drooping upper eyelid during certain mandibular movements, particularly jaw lowering or mandibular diduction. We present a case of Marcus Gunn syndrome.Observation This concerns a 10-year-old child with no notable medical history, whose mother consulted for retraction of the left upper eyelid that synergistically accompanied chewing movements, observed since birth. The interview revealed no consanguinity or similar cases in the family, no infectious or viral episodes during the mother's pregnancy, and no childhood traumas. The ophthalmological examination identified left-sided amblyopia with visual acuity of 10/10 in the right eye and 7/10 in the left eye. The neurological examination revealed:Fluctuating, moderate, and isolated ptosis on the left side.Retraction of the left upper eyelid when opening the mouth, with moderate synkinesis. The photomotor reflexes were present and symmetrical. Additionally, the somatic examination, including the rest of the neurological examination, showed no abnormalities. Magnetic resonance imaging returned normal results.Discussion The first case of Marcus Gunn syndrome was described in a 15-year-old girl by Robert Marcus Gunn in 1883, initially referred to as "Jaw-Winking Phenomenon." While it is typically congenital (representing 2 to 13% of congenital ptosis cases), this phenomenon may also be triggered by an infectious or viral event during pregnancy. Rare acquired cases have been reported following childhood traumas, inflammatory processes, or even tumor lesions. The syndrome is characterized by ptosis associated with mandibulopalpebral synkinesis. Ptosis is corrected by mouth opening or mandibular diduction and can occur in isolation or be accompanied by oculomotor disturbances. The syndrome is generally unilateral, rarely bilateral, and most commonly affects the left side, as observed in our case. It is typically transmitted in an autosomal dominant manner, with sporadic cases also reported. In our observation, this is the first diagnosed case in the family. The pathogenesis is not well understood, but it results from aberrant innervation of the levator muscle of the upper eyelid by motor fibers of the trigeminal nerve. Various etiological hypotheses include:Central neurogenic origin due to abnormal connections at multiple levels (between the pontine masticatory nucleus of the trigeminal nerve and the anterior quadrigeminal tubercles of the oculomotor nerve, an internuclear or infra-nuclear connection, or even abnormal cortical or subcortical connections).Peripheral neurogenic origin through in utero neurogenic atrophy with aberrant innervation.Muscular origin with atrophy of muscle fibers in the affected side's levator muscle of the upper eyelid. The frequency of amblyopia varies from 34% to 59% in different case series. Associated systemic anomalies are very rare and may include ectrodactyly, bilateral pes cavus with genu varum, bilateral cryptorchidism, supernumerary incisors, spina bifida, and cleft lip. The goal of treatment is to eliminate synkinesis, correct ptosis, and manage associated issues, especially amblyopia. Treatment options include muscle resection or suspension of the upper eyelid to the frontal muscle.Conclusion Marcus Gunn syndrome is a rare condition that combines ptosis with mandibulopalpebral synkinesis. It is likely caused by erratic innervation of the levator muscle of the upper eyelid by branches of the trigeminal nerve. It may be associated with other oculomotor or systemic disorders
Audience Take Away Notes:
- Marcus Gunn Syndrome, also known as Marcus Gunn Jaw-Winking Syndrome, is a rare congenital condition that primarily affects the eyes and facial muscles.
- Here are some key points about this syndrome:
- Involuntary Eyelid Movement: The hallmark characteristic of Marcus Gunn Syndrome is an involuntary movement of the upper eyelid when certain facial movements occur, particularly jaw movements. This means that when the individual opens their mouth, chews, or makes certain facial expressions, their upper eyelid may move up and down.
- Congenital Condition: Marcus Gunn Syndrome is present from birth and is typically noticed during early childhood or infancy. It is considered a congenital disorder, meaning it results from developmental issues during fetal growth.
- Cause: The exact cause of Marcus Gunn Syndrome is not always clear, but it is thought to be related to abnormal connections or miswiring of the nerves that control the eyelid and jaw muscles. This miscommunication leads to the unusual eyelid movement.
- Unilateral or Bilateral: This condition can affect one eye (unilateral) or both eyes (bilateral), although unilateral presentation is more common.
- Severity Varies: The severity of Marcus Gunn Syndrome can vary among individuals. In some cases, the eyelid movement is subtle and hardly noticeable, while in others, it can be more pronounced.Treatment
- Options: Treatment options depend on the severity and impact of the condition. In mild cases, no treatment may be necessary. In more pronounced cases that affect vision or aesthetics, surgical correction may be considered to improve eyelid movement and alignment.
- Normal Vision: It's important to note that Marcus Gunn Syndrome does not typically affect vision itself; it's mainly a cosmetic concern due to the eyelid movement.Management and treatment decisions should be made in consultation with a healthcare professional, such as an ophthalmologist or a surgeon, who can assess the individual's specific condition and recommend appropriate steps if necessary.
