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Introduction
Case
A 34 year old male presents to the emergency department following a motor vehicle accident in which he struck a light post at low speeds. He was belted and the airbag was activated. There was no loss of consciousness or signifant systemic injuries, however he complains of decreased vision and monocular diplopia in the right eye. His past medical and ocular history is otherwise unremarkable.
The patient says the symptoms started soon after the incident, and feels the airbag impact was maximal over his right eye. On exam, visual acuity is 20/100 and 20/20 in the right and left eyes, respectively. Posterior segment exam is shown below:
While likely not present in this individual, what is the most common genetic cause of the abnormality causing this patient’s symptoms?
Pseudoexfoliation syndrome: INCORRECT
Pseudoexfoliation syndrome is an elastic microfibrillopathy characterized by fibrillogranular material found in the anterior segment. Although certainly associated with ectopia lentis, it is not the most common cause.
Marfan syndrome: CORRECT
Ehlers-Danlos syndrome: INCORRECT
Ehlers-Danlos syndrome is a group of connective tissue disorders characterized by a defect in the synthesis of collagen. It is a relatively common disorder and only very rarely causes ectopia lentis.
Myopia: INCORRECT
Myopia is not the most common genetic cause of ectopia lentis.
Ectopia lentis is a partial or complete displacement of the crystalline lens from its central position in the pupil, caused by broken or weakened zonules.1 It is most commonly caused by trauma, although it also is associated with many systemic conditions, including most commonly Marfan syndrome.2 Nontraumatic ectopia lentis occurs at an estimated prevalence of 6.4 per 100,000, and affects both males and females at an equal rate.3