Process for detecting increased risk of fetal chromosomal abnormality

Abstract

An increased risk of a fetal chromosomal abnormality, for example, fetal Down syndrome can be detected by separating or discriminating α-fetoproteins present in the body fluid of a pregnant woman, and measuring the proportion of one or more of the α-fetoproteins which have a specific sugar chain structure, relative to the total α-fetoproteins.

What is claimed is:  
     
         1 . A process for detecting an increased risk of a fetal chromosomal abnormality which comprises separating α-fetoproteins present in a body fluid of a pregnant woman on the basis of the difference between or among their sugar chain structures, measuring one or more of α-fetoproteins having a specific sugar chain structure, and detecting the increased risk on the basis of a result of the measurement.  
     
     
         2 . A process according to  claim 1 , wherein the α-fetoproteins having a specific sugar chain structure are those having a bi-antennarly complex type sugar chain or a sugar chain formed by the conversion of said bi-antennarly complex type sugar chain.  
     
     
         3 . A process according to  claim 1 , wherein the α-fetoproteins having a specific sugar chain structure are those which can be separatated by use of a protein capable of recognizing a specific sugar chain of at least one of α-fetoproteins.  
     
     
         4 . A process according to  claim 3 , wherein the protein capable of recognizing a specific sugar chain is  Lens culinaris  agglutinin, erythroagglutinating phytohemagglutinin-E4 or concanavalin A.  
     
     
         5 . A process according to  claim 1 , wherein the chromosomal abnormality is an autosomal abnormality or a sex chromosomal abnormality.  
     
     
         6 . A process according to  claim 1 , wherein the body fluid is amniotic fluid, plasma or serum.  
     
     
         7 . A process according to  claim 1 , wherein the body fluid is collected from a pregnant woman in the 10 to 20 weeks of gestation.  
     
     
         8 . A reagent for detecting an increased risk of a fetal chromosomal abnormality which comprises a protein capable of recognizing a specific sugar chain of at least one of α-fetoproteins and is used in the process of  claim 3 .  
     
     
         9 . A reagent according to  claim 8 , wherein the specific sugar chain of α-fetoproteins is a bi-antennarly complex type sugar chain or a sugar chain formed by the conversion of said bi-antennarly complex type sugar chain.  
     
     
         10 . A reagent according to  claim 8 , wherein the protein capable of recognizing a specific sugar chain is  Lens culinaris  agglutinin, erythroagglutinating phytohemagglutinin-E4 or concanavalin A.  
     
     
         11 . A reagent according to any one of  claim 8  to  10 , wherein the chromosomal abnormality is an autosomal abnormality or a sex chromosomal abnormality.  
     
     
         12 . A process for detecting an increased risk of a fetal chromosomal abnormality which comprises separating α-fetoproteins present in a body fluid of a pregnant woman on the basis of the difference between or among their sugar chain structures, measuring the proportion of one or more of the α-fetoproteins which have a specific sugar chain structure, relative to the total α-fetoproteins, and detecting the increased risk on the basis of a result of the measurement.  
     
     
         13 . A process according to  claim 12 , wherein the α-fetoproteins having a specific sugar chain structure are those having a bi-antennarly complex type sugar chain or a sugar chain formed by the conversion of said bi-antennarly complex type sugar chain.  
     
     
         14 . A process according to  claim 12 , wherein the α-fetoproteins having a specific sugar chain structure are those which can be separated by use of a protein capable of ecognizing a specific sugar chain of at least one of α-fetoproteins.  
     
     
         15 . A process according to  claim 14 , wherein the protein capable of recognizing a specific sugar chain is  Lens culinaris  agglutinin, erythroagglutinating phytohemagglutinin-E4 or concanavalin A.  
     
     
         16 . A process according to  claim 12 , wherein the chromosomal abnormality is an autosomal abnormality or a sex chromosomal abnormality.  
     
     
         17 . A process according to  claim 12 , wherein the body fluid is amniotic fluid, plasma or serum.  
     
     
         18 . A process according to  claim 12 , wherein the body fluid is collected from a pregnant woman in the 10 to 20 weeks of gestation.  
     
     
         19 . A kit for detecting an increased risk of a fetal chromosomal abnormality, which comprises (1) a lectin capable of recognizing a specific sugar chain of at least one of α-fetoproteins and (2) an anti-α-fetoprotein antibody.  
     
     
         20 . A kit according to  claim 19 , wherein the lectin is  Lens culinaris  agglutinin, erythroagglutinating phytohemagglutinin-E4 or concanavalin A.  
     
     
         21 . A kit for detecting an increased risk of a fetal chromosomal abnormality which comprises (1) a lectin capable of recognizing a specific sugar chain of at least one of α-fetoproteins, (2) an anti-α-fetoprotein antibody capable of binding to all α-fetoproteins irrespective of whether the lectin binds to α-fetoproteins or not and (3) an anti-α-fetoprotein antibody having a low reactivity with an α-fetoprotein(s) having the lectin attached thereto but having a high reactivity with an α-fetoprotein(s) to which the lectin does not-bind.  
     
     
         22 . A kit according to  claim 21 , wherein the lectin is  Lens culinaris  agglutinin, erythroagglutinating phytohemagglutinin-E4 or concanavalin A.