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.

Vitreous amyloidosis as primary manifestation of disease: case report

A 35-year-old woman with progressive decrease of vision in both eyes and with no other associated symptoms, manifested as the only antecedent, the death of her brother due to amyloidosis. The visual acuity was counting fingers at 30 centimetres in the right eye and 20/70 in the left eye. In ophthalmoscopy of the right eye, a white, homogeneous vitreous, that was difficult to assess in detail, was observed, and in the left eye a whitish vitreous with band-like opacities in the cortical region. Vitrectomy was performed in the right eye, and a study with specific stains showed positive for amyloid material. A case is reported of amyloidosis diagnosed with specific stains in a vitreous sample for which the initial and only manifestation was the presence of vitreous opacities. The processing of these samples should be considered in patients with family history, early vitreous opacities, negative results of systemic biopsy, or atypical course of the disease.

Vitreous amyloidosis with autonomic neuropathy of the digestive tract associated with a novel transthyretin p.Gly87Arg variant in a Bangladeshi patient: a case report

BACKGROUND

Hereditary transthyretin amyloidosis is an autosomal dominant inherited disorder, first described in families with sensorimotor and autonomic neuropathy. Since its first description, more than 120 amyloidogenic transthyretin mutations have been reported with various geographic distributions and associated with a wide range of phenotypes involving the peripheral nerve, the heart, the gastrointestinal tract, the eyes, the central nervous system, or the kidneys. In some cases of transthyretin amyloidosis, the first clinical manifestation is vitreous opacity.

CASE PRESENTATION

A 46-year-old Bangladeshi woman presented with vitreous amyloidosis and progressive autonomic neuropathy of the digestive tract as initial clinical manifestations, with no clinical evidence of cardiac, renal, central nervous system, or peripheral nerve dysfunction. A novel transthyretin mutation, p.Gly87Arg, was identified in the heterozygous state in this proband of Bangladeshi origin. Histological examination of accessory salivary glands and gastric biopsies revealed Congo-red-positive deposits. Laser microdissection of salivary gland Congo-red deposits and tandem mass spectrometry-based proteomic analysis identified the mutated transthyretin peptide containing the arginine residue at position 87 of the mature protein.

CONCLUSIONS

Vitreous amyloidosis should be considered a differential diagnosis of uveitis, in particular transthyretin amyloidosis. Proteomics data from our case, consistent with the genetic findings, highly suggests that this new p.Gly87Arg variant is amyloidogenic. Here, we described the second case of transthyretin amyloidosis reported in a Bangladeshi patient.

Vitreous Amyloidosis as the Presenting Symptom of Familial Amyloid Polyneuropathy TTR Val30Met in a Portuguese Patient

Familial amyloid polyneuropathy (FAP) is a group of disorders characterized by the extracellular deposition of amyloid substance in various tissues. The peripheral nervous system and the heart are the main target organs, but the eye may also be involved. We report a case of vitreous amyloidosis as the first manifestation of FAP in a 66-year-old Portuguese man without a family history.