In addition, two novel targets of HTRA1 have been identified: EFEMP1, an extracellular matrix protein mutated in Doyne honeycomb retinal dystrophy, a genetic eye disease similar to AMD, and thrombospondin 1 (TSP1), an inhibitor of angiogenesis.
The studies were done using a mouse model of the inherited macular dystrophy Doyne Honeycomb Retinal Dystrophy/Malattia Leventinese (DHRD/ML) which is caused by a p.Arg345Trp mutation in EFEMP1.
Mutation screening of the EFEMP1 gene and haplotype analysis were performed in the family, an Indian ML/DHRD family, and a branch of 1 of 39 ML/DHRD families in the United States, in which all affected patients shared a common haplotype.
First, genetically engineered mice that target genes related to juvenile macular dystrophies are the most common models, and they include abcr(-/-) (Stargardt disease), transgenic ELOVL4 (Stargardt-3 dominant inheritary disease), Efemp1(R345W/R345W) (Doyne honeycomb retinal dystrophy), and Timp3(S156C/S156C) (Sorsby fundus dystrophy) mice.
Formation and progression of sub-retinal pigment epithelium deposits in Efemp1 mutation knock-in mice: a model for the early pathogenic course of macular degeneration.
The inherited macular degeneration Doyne honeycomb retinal dystrophy/Malattia Leventinese is thought to be caused by an R345W mutation in the EFEMP1 gene (also called fibulin-3).
The inherited macular degeneration Doyne honeycomb retinal dystrophy/Malattia Leventinese is thought to be caused by an R345W mutation in the EFEMP1 gene (also called fibulin-3).
The inherited macular degeneration Doyne honeycomb retinal dystrophy/Malattia Leventinese is thought to be caused by an R345W mutation in the EFEMP1 gene (also called fibulin-3).
The Arg345Trp mutation on exon 10 of the EGF-containing fibulin-like extracellular matrix protein 1 (EFEMP1) gene causes two clinical phenotypes of early onset drusen (Doyne honeycomb retinal dystrophy and Malattia Leventinese), yet does not appear to be involved in other early onset drusen phenotypes or typical AMD.
The Arg345Trp disease-associated allele in the EFEMP1 gene was confirmed in individuals with malattia leventinese and Doyne honeycomb retinal dystrophy.
At least two forms, Doyne honeycomb retinal dystrophy (DHRD) and Malattia Leventinese (MLVT), are associated with a single missense mutation (R345W) in the gene encoding the EGF-containing fibulin-like extracellular matrix protein-1 (EFEMP1) and are now thought to represent a single entity.
Given that mutations in EFEMP1 have been recently described in patients with Doyne honeycomb retinal dystrophy, EFEMP2 becomes a good candidate for such disorders.
These include MSH2, which is responsible for HNPCC, FSHR, the gene responsible for FMPP, EFEMP-1, the gene mutated in DHRD, GTBP, a DNA repair gene, and SPTBN1, nonerythryocytic beta-spectrin.