Vitreous amyloidosis caused by a Lys55Asn variant in transthyretin: A case report

BACKGROUND: Amyloidosis is caused by misfolding of proteins and is characterized by formation of extracellular aggregates of insoluble fibrin. The primary effects in the eye include sharp deterioration of visual acuity as a result of vitreous opacity. According to the local and systemic distribution characteristics of amyloid deposits and their fibrin components, amyloidosis can be classified as primary, secondary or familial. Therefore, we report a typical case of vitreous amyloidosis in hereditary transthyretin amyloidosis (hATTR) to improve ophthalmologists’ understanding of the disease and reduce misdiagnosis and recurrence. CASE SUMMARY: The patient was a 49-year-old man who complained of progressive visual decline in both eyes over a 2-mo period. No systemic diseases such as diabetes or hypertension were reported, and no obvious family history of disease was identified. The patient’s visual acuity was HM/10 cm in the right eye and 0.06 in the left eye. He had a transparent cornea in both eyes, with a normal anterior depth, clear aqueous humor, no obvious iris abnormalities, round pupils of approximately 3 mm in diameter, normal direct and indirect light reflexes, and normal intraocular pressure. After various examinations, the patient was diagnosed with binocular vitreous amyloidosis secondary to hATTR associated with a Lys55Asn variant in TTR. The binocular visual acuity recovered to 1.0 after binocular vitrectomy. CONCLUSION: Vitreous amyloidosis is rare in the clinic and gene testing can assist the diagnosis accurately and effectively.