Angiotensin-converting enzyme (ACE) gene polymorphism in patients with sarcoidosis

Angiotensin-converting enzyme deletion allele is beneficial for the longevity of Europeans

The human angiotensin converting enzyme (ACE) gene is one of the most investigated candidate genes for cardiovascular diseases (CVD), but the understanding of its role among the elderly is vague. Therefore, this study focuses at: (a) testing the association of ACE polymorphism with CVD risk factors among the elderly, and (b) detecting the possible unequal distribution of ACE genotypes between senescent and younger segments of the European populations. The association of ACE I/D polymorphism with CVD health status [hypertension (HT), obesity, dislypidemia] in 301 very old subjects (88.2 ± 5 years; F/M = 221/80) was tested by means of logistic regression analysis. The meta-analysis of D allele frequency in general vs. elderly (80+ years) groups was conducted using all publicly available data for European populations comprising both age cohorts. Multiple multinomial logistic regression revealed that within this elderly sample, age (younger olds, 80-90 years), female sex (OR = 3.13, 95% CI = 1.59-6.19), and elevated triglycerides (OR = 2.53, 95% CI = 1.29-4.95) were positively associated with HT, while ACE polymorphism was not. It was also established that the DD genotype was twice as high in 80+ cohort compared to general population of Croatia (p < 0.00001). This trend was confirmed by the meta-analysis that showed higher D allele frequencies in olds from nine of ten considered European populations (OR = 1.19, 95% CI = 1.08-1.31). The data in elderly cohort do not confirm previously reported role of ACE DD genotype to the development of HT. Moreover, meta-analysis indicated that ACE D allele has some selective advantage that contributes to longevity in majority of European populations.

Role of genetic polymorphisms in ACE and TNF-alpha gene in sarcoidosis: a meta-analysis

A great number of association studies have been performed to identify the genes involved in the etiology and prognosis of sarcoidosis. We performed a systematic review of case-control studies through the PubMed database and evaluated them for a possible inclusion into a meta-analysis in order to assess whether the reported genetic polymorphisms are the risk factors of sarcoidosis. Case-control studies with clear diagnostic criteria and interventions were included. Only investigations of a single polymorphism/gene involvement in sarcoidosis reported more than five times were selected. Aggregating data from 12 studies on ID/ACE polymorphisms, the odds ratio (OR) for sarcoidosis, if the polymorphism was considered under the dominant genetic model, was not significantly increased: 1.19 (95% CI 0.98-1.43); OR under the recessive model was 1.20 (95% CI 0.98-1.46). In seven case-control studies on -308/TNF-alpha polymorphism, the OR for sarcoidosis if the polymorphism considered under the dominant genetic model was significantly increased at 1.47 (95% CI 1.03-2.08); the OR under the recessive model was 1.39 (95% CI 0.67-2.90). In conclusion, the results showed that the TNF-alpha genotype could be a significant risk factor for sarcoidosis, whereas the risk of sarcoidosis due to the ACE genotype was not substantially elevated.

Angiotensin-converting enzyme gene polymorphisms in patients with pulmonary sarcoidosis: impact on disease severity

Angiotensin converting enzyme (ACE) is a metallopeptidase with a key function in the regulation of blood pressure and volume. The ACE1 gene, on chromosome 17, contains a insertion/deletion (I/D) polymorphism in intron 16. The D allele of this polymorphism is linked with raised serum ACE (sACE) levels. Sarcoidosis is a systemic disease of granulomatous inflammation that primarily affects the lung and lymph system. It is often accompanied by elevated sACE related to ACE production from granuloma cells. The ACE I/D polymorphism has been tested for association or linkage with the risk of sarcoidosis. Though published results are conflicting, there seems to be suggestive evidence of a minor pro-inflammatory influence of the ACE D allele in sarcoidosis. At present, a more accurate interpretation of sACE levels in diagnosis and monitoring of sarcoidosis seems to be the main value of ACE I/D genotyping.

Ace gene I/D polymorphism and sarcoidosis pulmonary disease severity

Previous studies of the insertion/deletion (I/D) polymorphism of the angiotensin-converting enzyme (ACE) gene in sarcoidosis have revealed both ethnic heterogeneity of I/D frequencies and controversy surrounding the association between the polymorphism and severity of disease. The objective of this study was, therefore, to clarify the role of the ACE I/D polymorphism in (1) disease susceptibility, (2) pulmonary disease severity (with particular reference to pulmonary fibrosis), and (3) pulmonary disease progression, in two distinct European sarcoidosis populations. Standard chest radiographic staging was performed on 118 UK and 56 Czech white patients with sarcoidosis at 2 yr from presentation. Pulmonary function data were analyzed, and patients were then categorized according to disease severity. A PCR-SSP assay was used to determine the ACE I/D genotype of each patient studied. The I/D allele frequencies from these patients were compared with frequencies from ethnically matched UK (n = 386) and Czech (n = 179) control subjects using a chi-square contingency table. No significant differences were seen in the distribution of the ACE I/D genotypes, allele frequencies or phenotype frequencies. Furthermore, no association was found between the ACE I/D polymorphism and pulmonary disease severity, fibrosis, and progression. We conclude that the ACE I/D polymorphism has no role in sarcoidosis susceptibility in European whites and that it is not a regulatory variant in this disease.

Angiotensin-converting enzyme (ACE) gene polymorphisms and familial occurrence of sarcoidosis

OBJECTIVES

The aim of this study was to test for genetic linkage and association between polymorphisms of the angiotensin-converting enzyme (ACE) gene and familial occurrence of sarcoidosis.

DESIGN, SETTING AND SUBJECTS

German families with more than one member suffering from sarcoidosis were contacted and a DNA bank was established. Sixty-two families (140 patients, 77 females and 63 males, and 104 unaffected relatives) were genotyped for the ACE gene insertion/deletion (I/D) polymorphism and for two flanking variable sites (ACE A-5466C and ACE 4656(CT)2/3). As controls, 100 DNAs from unrelated resident Caucasians (50 females, 50 males) were analysed. ACE allele and genotype frequencies were determined, and parametric linkage and affected sib pair analyses and transmission disequilibrium tests were performed.

RESULTS

There was a striking over-representation of the ACE I/D genotype DD in patients with sarcoidosis and their families as compared with controls of the study and well founded genotype frequencies from the literature. The same was evident for the accompanying genotypes CC and 2,2 of the flanking polymorphisms. Linkage between the segregation of ACE alleles and the disorder within families was clearly excluded for simple models of inheritance. However, there was a suggestive but not significant (P = 0.06) excess of allele sharing amongst affected siblings. There was no transmission disequilibrium for any ACE allele or haplotype.

CONCLUSIONS

ACE is involved in the pathogenesis of sarcoidosis, but the ACE polymorphisms are not an inherited main cause of the disease. They are more likely to modify the development of the disorder, and the ACE I/D genotype DD might be a promoter to clinical manifestation.

Angiotensin converting enzyme (ACE) gene polymorphism in sarcoidosis in relation to associated autoimmune diseases

OBJECTIVES

To investigate the significance of ACE gene insertion/deletion (I/D) polymorphism in the frequency of autoimmune manifestations in sarcoidosis.

DESIGN

In patients with sarcoidosis the ACE gene I/D polymorphism was detected with PCR on genomic DNA. The patients with sarcoidosis were divided according to the presence (n = 30) or absence (n = 32) of autoimmune manifestations. The former group was subdivided into thyroid autoimmunity (n = 10), gluten immune reactivity (n = 10) and gastric autoimmunity (n = 17).

SETTINGS

The patients were recruited at the Department of Pulmonary Medicine, and the study was conducted at the Department of Endocrinology, University of Lund, Malmö University Hospital, Malmö, Sweden.

SUBJECTS

Sixty-two patients with documented sarcoidosis (30 females, 32 males, median age/range at diagnosis of sarcoidosis 31.5/19-75 years, median age/range at study 47.5/22-81 years) were examined. A total of 107 healthy unrelated subjects without sarcoidosis (60 females, 47 males, median age/range at study 58/40-82 years) served as controls.

RESULTS

S-ACE values were significantly increased in patients compared to controls (P = 0.00001). The same was true in the subgroup of sarcoidosis patients with associated autoimmunity compared with those with isolated sarcoidosis (P = 0.0328). A significant association was seen between ACE gene polymorphism (II, ID, DD genotypes) and S-ACE levels in both patients and controls according to the order II < ID < DD. The observed genotype frequency distributions in the different study groups agreed the Hardy-Weinberg equilibrium without significant differences between the patients and the controls. Within the group with autoimmune manifestations the DD genotype was significantly over-represented in X-ray stage III compared to the other X-ray stages (P = 0.0181) and a significant increase in the DD genotype in X-ray stage III (P = 0.035) in the group with autoimmune manifestations compared to isolated sarcoidosis was detected.

CONCLUSION

We confirmed that the S-ACE levels corresponded to the order II < ID < DD in patients with sarcoidosis as well as in healthy controls. S-ACE levels were significantly higher in sarcoidosis patients with autoimmune manifestations. The frequency of the DD genotype was significantly increased in patients with autoimmune manifestations and major granuloma mass (X-ray stage III). The ACE D allele in its homozygous form may confer susceptibility for autoimmune manifestations in sarcoidosis, possibly via the high levels of S-ACE it encodes.