Sorsby Fundus Dystrophy (SFD)

Introduction

Sorsby fundus dystrophy (SFD) is an autosomal dominant macula dystrophy with middle age onset. Patients lose central vision as a result of extra-cellular deposits and thickening in Bruch’s membrane, sub-retinal neovascularization, and atrophy of the ocular tissues. The SFD phenotype shares extensive clinical similarity with age-related macular degeneration (AMD), in particular the more severe or “wet” form of AMD. Mutations in the gene encoding tissue inhibitor of metalloproteinases-3 (TIMP-3) have been shown to be responsible for SFD. These mutations are confined to exon 5 of TIMP-3 and its intron4/exon5 acceptor splice site

Referral information

Mutation screening is available for affected individuals with suspected SFD. Pre-symptomatic testing is available for families with a previously identified mutation.

Technical information

Mutation scanning is carried out by bi-directional sequencing of exon 5 and the intron 4/exon 5 splice acceptor site of the TIM-3 gene.

Price & reporting times

Test	Price NHS (£)	Price non-NHS (£)	TRT (calendar days)
Mutation scanning	POA	POA	28
Urgent/Predictive single mutation test	POA	POA	14

Test validation & quality assurance - information for users

Mutations are found in 33% of SFD cases referred for TIMP-3 screening. The laboratory is UKAS assessed against ISO 15189 standards.

Sample requirements

4ml EDTA blood sample

Referral guidelines

Please see our referral guidelines for more information.

OMIM Number(s) - 136900

Gene(s) - TIMP3