Protein Deposits Affecting the Eyes Can Be Common in hATTR Patients
About one-third of people in study, particularly women, show eye involvement
Eye involvement can become common over time in people with hereditary transthyretin amyloidosis (hATTR), a group of disorders that includes familial amyloid polyneuropathy (FAP), a study from Spain reported.
Researchers also noted that symptoms affecting the eyes are often slower to develop than others due to this disease. As such, this study “highlights the importance of routine ophthalmologic examinations in hATTR patients because many may show no signs of [eye] involvement at first, but may develop a wide variety of alterations as the disease evolves, many of them being treatable.”
The study, “Ophthalmologic Involvement in Patients with Hereditary Transthyretin Amyloidosis,” was published in the journal Retina.
Eye symptoms usually later to develop than neurologic or cardiac symptoms
hATTR refers to a group of disorders caused by mutations in the TTR gene that lead to toxic protein aggregates building in body tissues. FAP is a form of hATTR characterized by neurological symptoms.
These disorders can cause a number of eye-related problems, but they are usually slower to develop than neurological or heart symptoms, and detailed research on eye-related manifestations of the disease is limited.
“It is important to note that, although cardiac and neurologic manifestations tend to be the first signs to appear in hATTR patients … and [are] more common, other systems usually show alterations in time,” the researchers wrote. “Digestive and ocular involvement are often the next down the line.”
A team of researchers in Spain conducted detailed exams on 58 eyes of 29 people with hATTR who were receiving care at their center. Among the patients, 42% were women, 88.5% were white, and their mean age was 57.8.
About one-third of the eyes analyzed — 18 out of 58, or 34.6% — showed signs of disease involvement. The most common type, detected in all affected eyes, was vitreous amyloid deposits, or abnormal protein clumps described as having a “glassy” appearance.
Other abnormalities included protein deposits on the lens of the eye and in the blood vessels near the back of the eye. Of note, the lens is a transparent structure that helps focus the light rays that enter the eye in order to create an image.
Eye involvement was more common in women than in men; the eyes of two-thirds of the women in this study (66.7%) were affected. Patients with eye involvement were significantly more likely to have heart or neurological signs of the disease as well. However, there were no clear associations between eye involvement and the specific type of disease-causing mutation, including the more common Val30Met mutation found in 30.8% of this study’s patients.
Compared with unaffected eyes, eyes with disease involvement had significantly visual acuity, or the ability to see clearly, highlighting that eye involvement can affect patients’ quality of life. The researchers stressed that most of these forms of disease involvement are manageable with appropriate treatment.
As such, “ophthalmologic assessment is paramount to identify, follow, and in some cases treat the alterations that tend to appear in time in different parts of the eye” in people with hATTR, they noted.
“Larger studies will be necessary to establish which genetic mutations show a higher tendency to lead to ocular involvement,” the team added.