Assay for the diagnosis of macular degeneration

Abstract

An assay and kit for detecting N-retinylidene-N-retinylethanolamine (A2E) in a sample that uses a lipid binding protein, such as Saposin B, to capture A2E in the sample and assist in the extraction and measurement of A2E via mass spectroscopy. A2E thus serves as a marker for macular degeneration so that the assay and kit of the invention can be used to detect the presence or severity of macular degeneration.

What is claimed is: 
     
         1 . A kit for performing an assay for the diagnosis of macular degeneration, comprising:
 a quantity of a lipid binding protein; and   an immunoprecipitation substrate having a plurality antibodies to the lipid binding protein.   
     
     
         2 . The kit of  claim 1 , wherein the lipid binding protein is Saposin B. 
     
     
         3 . The kit of  claim 2 , wherein the immunoprecipitation substrate comprises protein G beads that have been incubated with antibodies targeting Saposin B. 
     
     
         4 . The kit of  claim 3 , wherein the antibodies are IgG anti-saposin B antibodies. 
     
     
         5 . A method of diagnosing a subject as having macular degeneration, comprising the steps of:
 obtaining a sample from the subject;   adding a quantity of a lipid binding protein to the sample to bind any N-retinylidene-N-retinylethanolamine in the sample; and   incubating the urine sample and the quantity of the lipid binding protein with an immunoprecipitation substrate having a plurality of antibodies to the lipid binding protein.   
     
     
         6 . The method of  claim 5 , further comprising the step of collecting any bound lipid binding protein and N-retinylidene-N-retinylethanolamine. 
     
     
         7 . The method of  claim 6 , further comprising the step of determining how much of any bound lipid binding protein and N-retinylidene-N-retinylethanolamine has been collected. 
     
     
         8 . The method of  claim 7 , wherein the lipid binding protein is Saposin B. 
     
     
         9 . The method of  claim 8 , wherein the immunoprecipitation substrate comprises protein G beads that have been incubated with antibodies targeting Saposin B. 
     
     
         10 . The method of  claim 9 , wherein the antibodies are IgG anti-saposin B antibodies. 
     
     
         11 . The method of  claim 9 , wherein the step of determining how much of any bound lipid binding protein and N-retinylidene-N-retinylethanolamine has been collected comprises the use of a mass spectrograph. 
     
     
         12 . The method of  claim 5 , wherein the sample is a urine sample.