{{Rsnum 
|rsid = 4340
|Gene = ACE
|Orientation=plus
|geno1=(C;C)
|geno2=(C;T)
|geno3=(T;T)
|Chromosome=17
|position=61565892
|Assembly=GRCh37
|GenomeBuild=37.1
|dbSNPBuild=131
}}[[rs4340]] is one of four SNPs representing perhaps the best studied [[ACE]] SNP. It is actually not a single nucleotide polymorphism at all; instead, it is an insertion/deletion of an [[Alu]] repetitive element in an intron of the [[ACE]] gene. Alleles containing the insertion are called "I" alleles, and "D" alleles lack the repetitive element. The other dbSNP entries all tagging this same single insertion/deletion SNP are:

* [[rs1799752]]
* [[rs13447447]] 
* [[rs4646994]]

There are numerous association studies reported for these SNPs. Examples:

*(I;I) homozygotes respond better to [[Viagra]] than (D;I) or (D;D) individuals, in a study of 100+ Caucasian men with erectile dysfunction. (OR 3.07, CI: 1.03 - 9.13, p=0.04). {{PMID|12837457}}

*(I;I) homozygotes are are higher risk for early-onset [[psoriasis]], with an odds ratio of 1.88 (CI: 1.12-3.15, p=0.016).{{PMID|18031458}}

{{PMID|18333655}} (I) is found more commonly in sherpas

{{ neighbor
| rsid = 1799752
| distance = 2
}}
{{ neighbor
| rsid = 4646994
| distance = 8
}}

{{PharmGKB
|RSID=rs4340
|Name_s=ACE:I/D, rs4646994, rs13447447, rs4340, rs1799752
|Gene_s=ACE
|Feature=Intron
|Evidence=PubMed ID:15121491
|Annotation=In a clinical trial of spironolactone in chronic heart failure patients, the I allele of ACE:I/D was associated with improved response to treatment.
|Drugs=spironolactone
|Drug Classes=
|Diseases=Heart Failure
|Curation Level=Curated
|PharmGKB Accession ID=PA165109821
}}

{{PharmGKB
|RSID=rs4340
|Name_s=ACE:I/D
|Gene_s=ACE
|Feature=Intron
|Evidence=PubMed ID:12837457
|Annotation=This variant is one of the insertion/deletion variant in intron 16 of the ACE gene. It is associated with sildenafil response for erectile dysfunction patients. Patients with D allele have elevated ACE serum concentrations and are less likely to respond to sildenafil.
|Drugs=sildenafil
|Drug Classes=
|Diseases=Erectile Dysfunction
|Curation Level=Curated
|PharmGKB Accession ID=PA161822203
}}
{{PMID Auto
|PMID=20570668
|Title=Genetic associations with mountain sickness in Han and Tibetan residents at the Qinghai-Tibetan Plateau
}}
{{omim
|id=106180
|rsnum=4340
|variant=0001
}}
{{PMID Auto
|PMID=21722816
|Title=Contribution of Deletion in Angiotensin-converting Enzyme But Not A1166C Angiotensin II Type-1 Receptor Gene Polymorphisms to Clinical Outcomes in Atherothrombotic Disease
}}{{PMID Auto
|PMID=17092869
|Title=Haplotype structure of five SNPs within the ACE gene in the Tunisian population.
}}

{{PMID Auto
|PMID=18637188
|Title=RAS gene polymorphisms, classical risk factors and the advent of coronary artery disease in the Portuguese population.
|OA=1
}}

{{PMID Auto
|PMID=18805939
|Title=Functional genetic polymorphisms and female reproductive disorders: part II--endometriosis.
|OA=1
}}

{{PMID Auto
|PMID=18974842
|Title=Gender differences in genetic risk profiles for cardiovascular disease.
|OA=1
}}
{{PMID Auto
|PMID=22908855
|Title=The linkage disequilibrium pattern of the angiotensin converting enzyme gene in Arabic and Asian population groups
}}{{PMID Auto
|PMID=23107763
|Title=Host genetic risk factors for community-acquired pneumonia.
}}
{{PMID Auto
|PMID=24860821
|Title=Gender Specific Association of RAS Gene Polymorphism with Essential Hypertension: A Case-Control Study
}}
{{PMID Auto
|PMID=24903972
|Title=Genetic predisposition to calcific aortic stenosis and mitral annular calcification
}}