April is Fabry Awareness Month. Fabry disease is a rare genetic disorder. It results from the buildup of a particular type of fat, called globotriaosylceramide, in the body's cells. The enzyme that breaks down globotriaosylceramide is absent or does not function properly. The fat accumulates in the walls of the blood vessels, decreasing blood flow to the kidneys, heart, skin and nervous system.
Beginning in childhood, this buildup causes signs and symptoms that affect many parts of the body. Characteristic features of Fabry disease include; episodes of pain, particularly in the hands and feet (acroparesthesias); clusters of small, dark red spots on the skin called angiokeratomas; a decreased ability to sweat (hypohidrosis); problems with the gastrointestinal system; ringing in the ears (tinnitus); and hearing loss.
Fabry disease also involves potentially life-threatening complications such as progressive kidney damage, heart attack, and stroke. Some affected individuals have milder forms of the disorder that appear later in life and affect only the heart or kidneys.
As optometrists, we are on the frontline to diagnose this often overlooked disease and allow our patients to seek critical treatment. All you need is a slit-lamp. There are some tell-tale ocular signs including:
Cornea verticillata: Cornea verticillata consist of bilateral whorl-like opacities located in the superficial corneal layers, most commonly in the inferior corneal area. These opacities are typically cream coloured, ranging from whitish to golden-brown. This manifest as early as in childhood. These corneal whorls are sometimes attributed to systemic drugs such as amiodarone. Amiodarone is an antiarrhythmic cardiac medication, commonly used in older patients. Keep in mind some patients may be on amiodarone due to Fabry disease affecting their heart. You should keep this in mind for younger patients - perhaps they are on amiodarone for complications secondary to Fabry?
Lenticular opacities: Anterior capsular or subcapsular cataract and a radial posterior subcapsular cataract (Fabry cataracts) have been reported in patients with Fabry disease. These are best seen with retro-illumination.
Vascular abnormalities: Conjunctival, retinal and choroidal vessels tend to show increased vessel tortuosity. Conjunctival abnormalities are commonly located in the inferior bulbar conjunctiva. In the retina, you may see tortuous “corkscrew’ vessels with segmental venous dilation, arteriolar narrowing and arterio-venous nicking.
Optometrists can make a huge difference in our patients’ lives, if we just look and act upon the signs we find. There is no cure for the Fabry disease, but patients often benefit from enzyme replacement therapy. If you suspect Fabry disease, you should refer the patient to their GP to commence genetic testing.