Susceptibility gene for alzheimer's disease

1. A method for indicating the pre-disposition of a male human subject to developing Alzheimer's disease, which method comprises:

(A) assaying a nucleic acid sample obtained from the subject for a p21 polymorphism to determine the allele present at said polymorphism, said p21 polymorphism being a p21 E2c31 C/A polymorphism;

and

(B) correlating the allele present at said polymorphism with the pre-disposition of said subject to developing Alzheimer's disease;

wherein a determination that said subject possesses a variant A allele of said p21E2c31 C/A polymorphism is taken as an indication that the subject is pre-disposed to Alzheimer's disease.

2. A method for diagnosing Alzheimer's disease in a male human subject exhibiting clinical symptoms of Alzheimer's disease, which method comprises:

(A) assaying a nucleic acid sample obtained from the subject for a p21 polymorphism to determine the allele present at said polymorphism, said p21 polymorphism being a p21 E2c31 C/A polymorphism;

and

(B) correlating the allele present at said polymorphism with the diagnosis of Alzheimer's disease in said subject;

wherein a determination that said subject possesses a variant A allele of said p21E2c31 C/A polymorphism is diagnostic that said subject has Alzheimer's disease.

3. A method of determining the existence of a genetic basis for Alzheimer's disease in a male human subject, which method comprises:

(A) assaying a nucleic acid sample obtained from the subject for a p21 polymorphism to determine the allele present at said polymorphism, said p21 polymorphism being a p21 E2c31 C/A polymorphism;

and

(B) correlating the allele present at said polymorphism with its contribution to the genetic basis for Alzheimer's disease in said subject;

wherein a determination that said subject possesses a variant A allele of said p21E2c31 C/A polymorphism indicates that a genetic variation that contributes to the genetic basis for Alzheimer's disease is present in said subject.

4. The method of claim 1 , wherein said assaying comprises a ligation detection reaction, single nucleotide primer extension, DNA sequencing or mass spectroscopy.

5. The method of claim 2 , wherein said assaying comprises a ligation detection reaction, single nucleotide primer extension, DNA sequencing or mass spectroscopy.

6. The method of claim 3 , wherein said assaying comprises a ligation detection reaction, single nucleotide primer extension, DNA sequencing or mass spectroscopy.

7. A method of determining the existence of a genetic basis for earlier onset of Alzheimer's disease in a female human subject exhibiting clinical symptoms of Alzheimer's disease, which method comprises:

(A) assaying a nucleic acid sample obtained from the subject for a p21E2c31 C/A polymorphism to determine the allele present at said polymorphism, and

(B) correlating the allele present at said polymorphism with the existence of a genetic basis for earlier onset of Alzheimer's disease in said subject, wherein a determination that said subject possesses a variant A allele of said p21E2c31 C/A polymorphism indicates that a genetic variation that contributes to the genetic basis for earlier onset of Alzheimer's disease is present in said subject, wherein said assaying comprises a ligation detection reaction, single nucleotide primer extension, DNA sequencing or mass spectroscopy.

8. The method of claim 1 , wherein said assaying employs a DNA microarray.

9. The method of claim 2 , wherein said assaying employs a DNA microarray.

10. The method of claim 3 , wherein said assaying employs a DNA microarray.

11. The method of claim 7 , wherein said assaying employs a DNA microarray.

12. The method of claim 1 , wherein said method further comprises determining whether said male human subject possesses the variant T allele of the p21E3+20 C/T polymorphism in the p21cip1 gene, wherein the presence of said variant T allele of said p21E3+20 C/T polymorphism is further indicative that said subject is pre-disposed to Alzheimer's disease.

13. The method of claim 2 , wherein said method further comprises determining whether said male human subject possesses the variant T allele of the p21E3+20 C/T polymorphism in the p21cip1 gene, wherein the presence of said variant T allele of said p21E3+20 C/T polymorphism is further diagnostic that said subject has Alzheimer's disease.

14. The method of claim 3 , wherein said method further comprises determining whether said male human subject possesses the variant T allele of the p21E3+20 C/T polymorphism in the p21cip1 gene, wherein the presence of said variant T allele of said p21E3+20 C/T polymorphism is further indicative that a genetic variation that contributes to the genetic basis for Alzheimer's disease is present in said subject.