Vitreous amyloidosis in two large mainland Chinese kindreds resulting from transthyretin variant Lys35Thr and Leu55Arg.

Objective: To describe the clinical and pathological findings of two large mainland Chinese kindreds with vitreous amyloidosis and associated transthyretin mutation. Methods: Twenty individuals from two kindreds with vitreous amyloidosis were ascertained. The transtheretin (TTR) gene of each individual was analyzed, and a clinical examination was obtained on the index patient. Results: Vitreous amyloidosis and radiculopathy were the significant findings in affected individuals. Vitrectomy was performed on the severely affected individuals, with resulting postoperative visual acuity of 20/80 to 20/25. Congo red staining demonstrated amyloid in the vitreous specimen. In Case A, DNA sequencing of exon 2 in the TTR gene revealed a base-pair substitution at codon 35, AAG>ACG (Lys35Thr). In Case B, a missense mutation of leucine-to-arginine substitution was identified at amino acid position 55 in exon 3, CTG>CGG (Leu55Arg). Conclusions: TTR Lys35Thr and Leu55Arg mutations are associated with vitreous amyloidosis. The phenotype is variable, with vitreous opacities occurring earlier, and sometimes as the sole signs of amyloidotic polyneuropathies (FAPs). Vitrectomy improves vision in some patients with vitreous amyloidosis.