Case Reveals Late-onset Eye Problems May Be Sign of Severe Disease
A man with familial amyloid polyneuropathy (FAP) developed eye problems years after he was found to have an uncommon disease-causing mutation called ATTRD18E, according to a case report from Canada.
Abnormal findings included vitreous opacities, or eye floaters, and retinal angiopathy — a condition in which blood vessels at the back of the eye become damaged. Conjunctival lymphangiectasia, a condition in which lymph vessels in the membrane that covers the front of the eye become unusually dilated, was also seen.
“These ocular findings may serve as a relevant biomarker for severe disease prognosis in ATTRD18E amyloidosis,” the researchers wrote.
The case report, “Conjunctival lymphangiectasia and retinal angiopathy in hereditary transthyretin amyloidosis,” was published in the International Journal of Retina and Vitreous.
FAP is caused by mutations in the gene that provides instructions for making a protein called transthyretin (TTR). Mutations cause TTR to fold into the wrong shape and clump together in various tissues. These protein clumps, called amyloid deposits, typically accumulate in nerves, as well as in the kidneys and the heart. When they accumulate in the eyes, however, they may cause serious eye problems.
Changes in the retina and the cornea have been suggested as early biomarkers of FAP. However, for many uncommon forms of the disease, eye changes are not well-documented, particularly when they occur relatively late in the course of the disease. The retina is the layer at the back of the eye that absorbs light and enables vision, while the cornea is the transparent layer covering the front of the eye.
In the report, a team of investigators in Canada described the case of a 43-year-old Caucasian man with FAP who experienced a series of eye changes. His diagnosis was made based on results from a genetic test that revealed the presence of an uncommon disease mutation, called ATTRD18E, almost 20 years earlier.
The man was referred to specialists because he had floaters and light flashes in his vision that were progressively getting worse. His right eye was also producing an excessive amount of tears. Floaters and flashes had been present for 10 years, but they had never been evaluated in detail by an eye doctor.
The man also had widespread symptoms of the disease, which affected the heart, blood vessels, and lungs. His treatment regimen included Onpattro (patisiran) to lower the production of TTR by the liver, and acetylsalicylic acid and warfarin to thin the blood.
Best corrected visual acuity — a measure of the best possible vision that an eye can achieve with the use of contact lenses or glasses — was 20/20, meaning it was normal.
Further examination revealed that the membrane that covers the front of the eye, called the conjunctiva, had a nodular, jelly-like appearance, which was consistent with conjunctival lymphangiectasia.
There was a large vitreous opacity in his left eye, and ruptured, leaky, and tortuous blood vessels, with focal deposits along their walls, “presumed to be amyloid.”
At a two-year follow-up visit, the man’s vision acuity remained normal. Most ocular findings were unchanged, with the exception of the leaky blood vessels, which appeared in greater number in both eyes.
“As treatment for ATTR amyloidosis advances, patients are living longer and the importance of detecting, monitoring, and treating ocular manifestations becomes more crucial, particularly as current medical and surgical treatment options do not address ocular symptoms,” the team wrote.
Further studies are needed to determine the prognosis and incidence of eye changes in patients with FAP and similar disorders, the researchers added.