Pathogenic variants in plakophilin-2 gene (PKP2) are associated with better survival in arrhythmogenic right ventricular cardiomyopathy.

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is mainly caused by mutations in genes encoding desmosomal proteins. Variants in plakophilin-2 gene (PKP2) are the most common cause of the disease, associated with conventional ARVC phenotype. The study aims to evaluate the prevalence of PKP2 variants and examine genotype-phenotype correlation in Polish ARVC cohort. All 56 ARVC patients fulfilling the current criteria were screened for genetic variants in PKP2 using denaturing high-performance liquid chromatography or next-generation sequencing. The clinical evaluation involved medical history, electrocardiogram, echocardiography, and follow-up. Ten variants (5 frameshift, 2 nonsense, 2 splicing, and 1 missense) in PKP2 were found in 28 (50%) cases. All truncating variants are classified as pathogenic/likely pathogenic, while the missense variant is classified as variant of uncertain significance. Patients carrying a PKP2 mutation were younger at diagnosis (p = 0.003), more often had negative T waves in V1-V3 (p = 0.01), had higher left ventricular ejection fraction (p = 0.04), and were less likely to present symptoms of heart failure (p = 0.01) and left ventricular damage progression (p = 0.04). Combined endpoint of death or heart transplant was more frequent in subgroup without PKP2 mutation (p = 0.03). Pathogenic variants in PKP2 are responsible for 50% of ARVC cases in the Polish population and are associated with a better prognosis. ARVC patients with PKP2 mutation are less likely to present left ventricular involvement and heart failure symptoms. Combined endpoint of death or heart transplant was less frequent in this group.

GROWTH RATE OF PARAGANGLIOMAS RELATED TO GERMLINE MUTATIONS OF THE SDHX GENES.

OBJECTIVE: The purpose was to determine the growth rate of succinate dehydrogenase subunit (SDHx) gene-related paragangliomas based on computed tomography (CT) measurements. METHODS: Twenty-seven patients with SDHx mutations who underwent subsequent CT examinations were enrolled in the study. Tumors were classified as head and neck (HNP), thoracic, or abdominal/pelvic paragangliomas (PGLs). The percentage volume increase and volume doubling time were estimated. RESULTS: We analyzed 56 PGLs (21 with SDHD, 6 with SDHB mutations) in 27 patients (16 men, 11 women; mean age 37.7 years). The estimated median of the follow-up was 23 months. Twenty-two (39.3%) PGLs were located in the abdomen, 8 (14.3%) in the thorax, and 26 (46.4%) in the head and neck region. The median volume growth rate was estimated at 10.4% per year (interquartile range [IQR]: -1.3; 36.3). The volume doubling time was estimated as 7.01 (2.24;+∞) years. By tumor site, the estimated medians of the annual volume growth rates were 13.6% (IQR:0.8 -30.4) for HNP, -6.06% (IQR: -1.79;47.32) for thoracic PGLs, and 10.5% (IQR: -2.2;44.6) for abdominal PGLs. The volume doubling time was 5.44 years (2.61; 87.0) for HNP, 11.8 years (1.79;+∞) for thoracic PGLs, and 6.94 years (1,88;+∞) for abdominal PGLs. There was no significant difference in the volume growth rate according to tumor location or initial size (P>.7 and P = .07, respectively) or gene mutation type (SDHB vs. SDHD, P>.8). CONCLUSION: PGLs related to SDHx mutations are slowly growing tumors. There were no correlations between tumor location, growth rate or initial size over a 23-month follow-up period. ABBREVIATIONS: CT = computed tomography HNP = head and neck paraganglioma IQR = interquartile range PGL = paraganglioma PPGL = pheochromocytoma and paraganglioma SDH = succinate dehydrogenase.

Evaluation of Head and Neck Paragangliomas by Computed Tomography in Patients with Pheochromocytoma-Paraganglioma Syndromes.

BACKGROUND: Hereditary head and neck paragangliomas (HNP) are very often associated with pheochromocytoma-paraganglioma syndromes, which are caused by mutations in genes encoding subunits of succinate dehydrogenase (SDHx) complex. The aim of this study was to determine the frequency and location of HNP among SDHx carriers. MATERIAL/METHODS: A total of 72 patients with SDHx mutations underwent computed tomography examinations of the head and neck. HNP were present in 44 (61.1%) out of 72 patients (31 SDHD, 11 SDHB, 2 SDHC); 113 HNP were found; the most common were carotid paragangliomas (59) and vagal paragangliomas (27). RESULTS: The HNP were statistically more frequent in carriers of SDHD mutations compared to carriers of SDHB mutations (72.1% vs. 43.5%, p=0.033). Multiple tumors more often occurred in patients with SDHD mutations 26/31 (83.9%) than in patients with SDHB mutations 6/11 (54.5%) p=0.05. There was a significant difference in the prevalence of carotid paragangliomas between patients with SDHB and SDHD mutations (7/11 [63.6%] vs. 30/31 [96.8%], respectively, p=0.004). Patients with SDHD mutations more often had carotid paragangliomas located on the left side than on the right side, as compared to SDHB mutations 25/31 (80.6%) vs. 4/11 (36.4%), p=0.006. CONCLUSIONS: SDHx mutations predispose to multifocal and bilateral HNP. Carotid and vagal paragangliomas occurred most often. Patients with SDHD mutations are characterized by higher frequency of HNP than patients with SDHB mutations, which is mainly driven by higher frequency of carotid body tumors in patients with SDHD mutations. No difference in the frequency of head and neck paragangliomas in other locations was found.

Mediastinal paragangliomas related to SDHx gene mutations.

INTRODUCTION: Paragangliomas (PGLs) related to hereditary syndromes are rare mediastinal tumors. Paragangliomas are caused by mutations in genes encoding subunits of succinate dehydrogenase enzyme (SDH). AIM: To evaluate clinical, anatomical and functional characteristics of mediastinal paragangliomas related to SDHx gene mutations. MATERIAL AND METHODS: Retrospective analysis of 75 patients with confirmed SDHx gene mutations (24 patients with SDHB, 5 SDHC, 46 with SDHD mutations) was performed. Patients underwent evaluation using computed tomography (CT), somatostatin receptor scintigraphy (SRS) (99mTc-[HYNIC,Tyr3]-octreotide), 123I mIBG scintigraphy and urinary excretion of total methoxycatecholamines. RESULTS: Out of 75 patients, 16 (21%) patients (1 SDHB, 15 SDHD mutations) had 17 PGLs localized in the mediastinum. Fourteen PGLs were localized in the middle mediastinum (intrapericardial) and 3 PGLs in the posterior mediastinum. The median diameter of paragangliomas measured on the axial slice was 24.3 mm (interquartile range (IQR): 14.7-36.6), and the median volume was 2.78 ml (IQR: 0.87-16.16). Twelve out of 16 patients (75%) underwent SRS, and 11 of them (92.3%) had pathological uptake of the radiotracer. Eleven (68.75%) out of 16 patients underwent 123 I mIBG, with only 3 positive results. Symptoms of catecholamine excretion were observed in 3 patients with PGLs localized in the posterior mediastinum. All PGLs were benign except in 1 patient with the SDHB mutation and PGL detected in the posterior mediastinum, who had a metastatic disease. CONCLUSIONS: Most mediastinal paragangliomas were related to SDHD gene mutations. They were asymptomatic, localized in the medial mediastinum, intrapericardially.

Coexistence of Andersen-Tawil Syndrome with Polymorphisms in hERG1 Gene (K897T) and SCN5A Gene (H558R) in One Family.

BACKGROUND: Andersen-Tawil Syndrome (ATS) is a channelopathy caused by mutations in KCNJ2 gene. It is characterized by symptoms of ventricular arrhythmias, periodic paralysis or muscle weakness, and dysmorphic features. ATS can present with the triad of symptoms, any combination or none of them. Risk factors for dangerous arrhythmias are unknown. The study assessed the impact of K897T polymorphism in hERG1 gene and H558R polymorphism in SCN5A gene coexisting with R218Q mutation in KCNJ2 in one family on clinical manifestation. METHODS: Family members underwent clinical assessment, ECG and genotyping. Holter monitoring was performed in mutation carriers and additionally in one family member with no mutation, but with K897T polymorphism. RESULTS: Proband with ATS mutation, K897T and H558R polymorphisms and proband's sister with ATS mutation and K897T polymorphism presented following symptoms: loss of consciousness, bidirectional and polymorphic ventricular tachycardia and about 5000 ventricular extrasystoles. Symptoms presented by the member with only the ATS mutation and by member with ATS mutation and H558R polymorphism were not as severe. U wave appeared in all examined family members regardless of the mutation presence. Studied individuals with ATS mutation had the T-peak-U-peak interval longer than 200 ms. In all ATS mutation carriers it was longer than in family members with no mutation. T-peak-T-end interval was the longest (>120 ms) in members with coexisting mutation and K897T polymorphism. CONCLUSION: ATS severity possibly depends on other genes' polymorphisms. In the presented family, it could depend on the presence of K897T polymorphism in hERG1.

Usefulness of Somatostatin Receptor Scintigraphy (Tc-[HYNIC, Tyr3]-Octreotide) and 123I-Metaiodobenzylguanidine Scintigraphy in Patients with SDHx Gene-Related Pheochromocytomas and Paragangliomas Detected by Computed Tomography.

AIMS: The aim of this study was to assess the usefulness of somatostatin receptor scintigraphy (SRS) using (99m)Tc-[HYNIC, Tyr3]-octreotide (TOC) and 123I-metaiodobenzylguanidine (mIBG) in patients with SDHx-related syndromes in which paragangliomas were detected by computed tomography and to establish an optimal imaging diagnostic algorithm in SDHx mutation carriers. METHODS: All carriers with clinical and radiological findings suggesting paragangliomas were screened by SRS and 123I-mIBG. Lesions were classified by body regions, i.e. head and neck, chest, abdomen with pelvis and adrenal gland as well as metastasis. RESULTS: We evaluated 46 SDHx gene mutation carriers (32 index cases and 14 relatives; 28 SDHD, 16 SDHB and 2 SDHC). In this group, 102 benign tumors were found in 39 studied patients, and malignant disease was diagnosed in 7 patients. In benign tumors, the sensitivity of SRS was estimated at 77% and of 123I-mIBG at 22.0%. The SRS and mIBG sensitivity was found to be clearly region dependent (p < 0.001). The highest SRS sensitivity was found in head and neck paragangliomas (HNP; 91.4%) and the lowest was found in abdominal paragangliomas and pheochromocytomas (40 and 42.9%, respectively). The highest 123I-mIBG sensitivity was found in pheochromocytomas (sensitivity of 100%) and the lowest in HNP (sensitivity of 3.7%). In metastatic disease, SRS was superior to mIBG (sensitivity of 95.2 vs. 23.8%, respectively). CONCLUSION: SRS and 123I-mIBG single photon emission computed tomography (SPECT) sensitivity in SDHx patients is highly body region dependent. In malignant tumors, SRS is superior to 123I-mIBG SPECT.

Pheochromocytoma presenting as takotsubo-like cardiomyopathy following delivery.

OBJECTIVE: Diagnosis of pheochromocytoma during pregnancy can be difficult, and the tumor carries an unfavorable prognosis if not diagnosed and treated in a timely manner. METHODS: To present a case of Takotsubo-like cardiomyopathy characterized by transient left ventricular apical ballooning due to pheochromocytoma following delivery. RESULTS: A few hours after Caesarean section, a 32-year-old Caucasian female presented with pulmonary edema followed by cardiac arrest with echocardiographic and ventriculographic evidence of reversible acute myocardial failure characteristic of Takotsubo-like cardiomyopathy. A previously unrecognized adrenal pheochromocytoma was found during her clinical work-up. Left ventricle (LV) function normalized after surgical removal of the tumor, which was carried out after implementing an alpha-adrenoreceptor blockade. Hemorrhagic necrosis of the pheochromocytoma was seen on histopathologic analysis; this may have triggered the sequence of events leading to the development of Takotsubo-like cardiomyopathy and hemodynamic collapse. CONCLUSION: To the best of our knowledge, this is the first reported case of Takotsubo-like cardiomyopathy related to pheochromocytoma following delivery. This emphasizes the increased cardiovascular risk if pheochromocytoma is not diagnosed and treated in a timely manner, especially during pregnancy.

Outcomes of adrenal-sparing surgery or total adrenalectomy in phaeochromocytoma associated with multiple endocrine neoplasia type 2: an international retrospective population-based study.

BACKGROUND: The prevention of medullary thyroid cancer in patients with multiple endocrine neoplasia type 2 syndrome has demonstrated the ability of molecular diagnosis and prophylactic surgery to improve patient outcomes. However, the other major neoplasia associated with multiple endocrine neoplasia type 2, phaeochromocytoma, is not as well characterised in terms of occurrence and treatment outcomes. In this study, we aimed to systematically characterise the outcomes of management of phaeochromocytoma associated with multiple endocrine neoplasia type 2. METHODS: This multinational observational retrospective population-based study compiled data on patients with multiple endocrine neoplasia type 2 from 30 academic medical centres across Europe, the Americas, and Asia. Patients were included if they were carriers of germline pathogenic mutations of the RET gene, or were first-degree relatives with histologically proven medullary thyroid cancer and phaeochromocytoma. We gathered clinical information about patients'RET genotype, type of treatment for phaeochromocytoma (ie, unilateral or bilateral operations as adrenalectomy or adrenal-sparing surgery, and as open or endoscopic operations), and postoperative outcomes (adrenal function, malignancy, and death). The type of surgery was decided by each investigator and the timing of surgery was patient driven. The primary aim of our analysis was to compare disease-free survival after either adrenal-sparing surgery or adrenalectomy. FINDINGS: 1210 patients with multiple endocrine neoplasia type 2 were included in our database, 563 of whom had phaeochromocytoma. Treatment was adrenalectomy in 438 (79%) of 552 operated patients, and adrenal-sparing surgery in 114 (21%). Phaeochromocytoma recurrence occurred in four (3%) of 153 of the operated glands after adrenal-sparing surgery after 6-13 years, compared with 11 (2%) of 717 glands operated by adrenalectomy (p=0.57). Postoperative adrenal insufficiency or steroid dependency developed in 292 (86%) of 339 patients with bilateral phaeochromocytoma who underwent surgery. However, 47 (57%) of 82 patients with bilateral phaeochromocytoma who underwent adrenal-sparing surgery did not become steroid dependent. INTERPRETATION: The treatment of multiple endocrine neoplasia type 2-related phaeochromocytoma continues to rely on adrenalectomies with their associated Addisonian-like complications and consequent lifelong dependency on steroids. Adrenal-sparing surgery, a highly successful treatment option in experienced centres, should be the surgical approach of choice to reduce these complications.

Myocardial iron homeostasis in advanced chronic heart failure patients.

BACKGROUND: Although, correction of iron deficiency and/or anemia in heart failure (HF) with iron seems promising, little is known about myocardial iron load and homeostasis. Moreover iron supplementation indications are solely based on iron serum markers. The purpose was to assess myocardial iron (M-Iron), ferritin (M-FR), transferrin receptor (M-sTfR) in HF in relation to serum Iron markers. METHODS AND RESULTS: Study group 33 patients, left/right ventricle (LV/RV) (LVEDV 245 ± 84 ml; LVESV 189 ± 85 ml; LVEF 22 ± 11%; RVD 32 ± 10 mm), NTproBNP (5464 ± 4825 pg/ml). Iron homeostasis assessment serum: iron, FR, transferrin/saturation (TSAT), sTfR; myocardial: M-Iron (Instrumental Neutron Activation Analysis, µg/g), M-FR, M-sTfR (ELISA - ng/mg protein) in the explanted failing hearts (FH), compared to non-failing hearts (NFH n=11). In FH as compared to NFH, M-Iron was reduced in RV (174 ± 45 vs 233 ± 97, respectively, p=0.07), LV (189 ± 58 vs 265 ± 119, p=0.04), without significant changes in M-FR/M-sTfR. Out of all serum iron markers only sTfR was negatively correlated with M-Iron in either ventricle (RV r=-0.44, p=0.03, LV r=-0.38, p=0.07). With regard to serum iron status, based on TSAT, patients were divided into two subgroups: reduced (TSAT<15%; n=11) and not-reduced serum iron (TSAT ≥ 15%; n=22). Both subgroups had similar grade of LV/RV dysfunction, NT-proBNP levels. M-FR was lower in TSAT<15% than in TSAT ≥ 15% (LV -31 ± 26 vs 46 ± 29; p=0.07) and (RV -24 ± 24 vs 43 ± 29; p=0.02), without differences in M-Iron and M-sTfR. CONCLUSIONS: In HF, M-Iron levels were reduced. Serum iron markers did not reflect M-Iron levels, except for serum sTfR. In reduced serum iron group, decrease in myocardial storage protein M-FR was observed.

Influence of renin-angiotensin system gene polymorphisms on the risk of ST-segment-elevation myocardial infarction and association with coronary artery disease risk factors.

BACKGROUND: Recent advances in molecular biology have made it possible to identify numerous polymorphisms of the renin-angiotensin system, which play an important role in the etiology of cardiovascular disease. OBJECTIVE: The aims of the study were (i) to assess the distribution of the angiotensin II type 1 receptor (AGTR1) gene 1166A/C polymorphism and two polymorphisms of the angiotensinogen (AGT) gene (Met235Thr and Thr174Met) in patients with ST-segment-elevation myocardial infarction (STEMI) who underwent coronary angiography, compared with healthy volunteers; (ii) to determine if there was any correlation between these polymorphisms and risk of STEMI; and (iii) to assess the association of the examined polymorphisms with such classic cardiovascular risk factors as hypertension, diabetes mellitus, obesity (based on a body mass index ≥25 kg/m2), smoking, dyslipidemia, and family history of cardiovascular disease. METHODS: A total of 100 patients (mean age 57 ± 10 years [range 31-76 years]; 21% women) with diagnosed STEMI and a control group consisting of 95 healthy volunteers (mean age 38 ± 11 years [range 17-60 years]; 20% women) were investigated for the AGTR1 1166A/C polymorphism and two variants of AGT (Met235Thr and Thr174Met). All patients received standard therapy for STEMI. RESULTS: There were significant differences in the distribution of genotypes and the AGT Met174 allele for AGT Thr174Met polymorphism between patients and healthy subjects (p < 0.05). The AGTR1 1166A/C polymorphism genotype frequencies were significantly different in patients with hypertension compared with normotensive individuals. Specifically, the AGTR1 1166 AA genotype was twice as common in patients with hypertension as in those without (67% vs 33%), while the AC and CC genotypes were found predominantly in normotensive patients (p = 0.0016). The variant 1166C allele was much more common in patients without hypertension (67%) than in patients with hypertension (33%; p = 0.0006). The variant AGT Thr235 allele was more common in patients without a family history of cardiovascular disease than in patients with this risk factor (p < 0.05). The odds ratio (OR) for STEMI in patients with the heterozygous AGT 174 Thr/Met genotype was increased to 1.884 (95% confidence interval [CI] 1.03, 3.446; p < 0.05), while the OR calculated for carriers of the AGT Met174 allele was 2.038 (95% CI 1.129, 3.68; p = 0.0182). Significant genotypic associations of combinations of renin-angiotensin system gene polymorphisms in STEMI were not observed. CONCLUSIONS: The most powerful predictive value for STEMI was represented by the Thr/Met genotype and the Met174 allele of the AGT Thr174Met gene polymorphism. In our study, in contrast to observations reported by other authors, the AA genotype of the AGTR1 1166A/C gene polymorphism - much more than other genotypes - was associated with hypertension.

Dilated cardiomyopathy with profound segmental wall motion abnormalities and ventricular arrhythmia caused by the R541C mutation in the LMNA gene.

In laminopathies cardiac involvement is common with dilated cardiomyopathy associated with atrio-ventricular block and malignant ventricular arrhythmia found in vast majority of patients. However, the specific disease course can be very different even among members of the same family which makes genotype-phenotype correlations difficult. Here we describe a 19-year-old patient with the LMNA R541C mutation and compare the course of his disease with two previously reported cases of the same molecular defect. We found that our patient shared important features with the previously described other subjects: significant LV segmental contractility defects (dyskinesis of the inferior wall and akinesis of LV apex), the presence of LBBB without atrio-ventricular block on 12-lead standard ECG and ICD requirement. The important differences between our subject and previously reported cases were early presentation (first symptoms at the age of 11 years) and early, progressive LV dilatation. We conclude that the LMNA R541C mutation should be considered not only in patients with malignant ventricular arrhythmia and LV local wall motion abnormalities, but also in classic dilated cardiomyopathy with profound segmental LV contractility defects.

Cardiac rhabdomyoma in tuberous sclerosis: hyperactive Erk signaling.

Tuberous sclerosis (TS) is a neurological disorder associated with the formation of tumors in several organs. Cardiac rhabdomyomas are possibly the earliest symptom of TS. Although rhabdomyomas are present in about half of TS patients, little is known of their molecular background since these tumors are rarely resected. Here we present a patient diagnosed with TS, in whom rhabdomyoma has been excised due to deterioration of hemodynamics. We found, that the tumor remained heterozygous for the affected TSC2 gene. To analyze molecular mechanisms implicated in rhabdomyoma growth, we determined the status of mTOR, Akt and Erk pathways. We found that Akt was not upregulated, while mTOR, Erk and its substrates were hyperactive. Classic activator of Erk, MEK, was only modestly active. We hypothesize that rhabdomyoma arising in TS may progress due to Erk potentiation.

Alteration of myocardial sarcoplasmic reticulum Ca2+-ATPase and Na+-Ca2+ exchanger expression in human left ventricular volume overload.

BACKGROUND: Reduced myocardial contractility is often attributed to altered Ca(2+) transients and expression of Ca(2+)-ATPase of the SR (SERCA) and Na+/Ca(2+)exchanger (NCX) genes. AIMS: To assess myocardial expression of SERCA and NCX protein levels in left ventricular (LV) remodelling due to chronic severe mitral regurgitation (MR). METHODS: Myocardial expression of SERCA/NCX in biopsy specimens obtained during mitral surgery was assessed in 36 MR patients with LV remodelling and plasma neurohumoral/cytokine activation and in four non-failing hearts (NFH). RESULTS: Myocardial protein levels of SERCA were significantly (20%) lower in the MR group than in NFH group (p=0.016). No significant changes in NCX were observed. However, a lack of homogeneity with regard to SERCA/NCX proteins was observed. Moreover, SERCA was negatively correlated with BNP (r=-0.49, p=0.02), TNFalpha (r=-0.68, p=0.0005) and IL-6 (r=-0.52, p=0.02), whereas NCX was only negatively correlated with TNFalpha (r=-0.62, p=0.002). CONCLUSIONS: MR patients showed wide variations in SERCA/NCX protein expression. Myocardial protein levels of SERCA were significantly lower in the MR population. Moreover, a correlation between BNP, cytokines (IL-6, TNFalpha) and the expression of SERCA/NCX proteins was observed.

The C677T mutation in methylenetetrahydrofolate reductase gene, plasma homocysteine concentration and the risk of coronary artery disease.

BACKGROUND: The C677T mutation in methylenetetrahydrofolate reductase (MTHFR) gene is one of the causes of an elevated homocysteine plasma concentration and is probably one of the atherosclerotic risk factors. AIM: To assess the relationship between the presence of the MTHFR gene mutation, plasma homocysteine concentration and the risk of coronary artery disease (CAD). METHODS: The study group consisted of 120 consecutive patients (78% were male, mean age 59.2+/-9.6 years) with angiographically confirmed CAD and 106 healthy volunteers (76% were male, mean age 47.4+ or -6.0 years). The MTHFR gene mutation was detected based on the polymerase chain reaction and digestion with restrictive endonuclease HinfI. Total homocysteine plasma concentration was measured using HPLC. Folic acid and vitamin B12 plasma levels were assessed using the chemiluminescence method. Hyperhomocysteinemia was defined as homocysteine concentration > or =90 percentile of the control group which was > or =12.4 micro mol/L. RESULTS: The incidence of the mutation of allele T and the genotype TT was similar in patients and controls (51.7% vs 56.6%, and 9.2% vs 10.4%, NS, respectively). The folic acid and vitamin B12 levels were not related to the MTHFR genotype (folic acid: 8.1 ng/L in homozygotes TT vs 8.6 in heterozygotes CT and 8.3 in homozygotes CC; and vitamin B12: 273 pg/L vs 303.3 vs 314.3, respectively). Although homozygotes TT had significantly higher homocysteine concentration than heterozygotes and homozygotes CT or CC (15.4 vs 11.0 vs 11.2 micro mol/L, p<0.001), the odds ratio for CAD in genotype TT was 0.87 (95% CI 0.5-2.1, NS). The odds ratio in subjects with at least one mutated T allele was 0.82 (95%CI 0.5-1.4, NS). Homocysteine plasma concentration was significantly higher in patients with CAD than controls (12.8+/-5.1 vs 10.0+/-5.0 micro mol/L, p<0.001) and correlated significantly with folic acid (r= -0.28, p=0.0001), vitamin B12 (r= -0.19, p<0.005), age (r=0.35, p=0.0001) and creatinine (r=0.26, p=0.0001). The odds ratio for CAD in subjects with hyperhomocysteinemia was 7.1 (95%CI 3.4-14.9, p=0.001) and was 2.6 (95%CI 1.6-4.1, p=0.0001) with a homocysteine increase of 5 micro mol/L. Multivariate analysis showed that hyperhomocysteinemia was an independent risk factor of CAD (OR 2.7, 95%CI 1-7.2, p<0.05). Conclusions. Hyperhomocysteinemia rather than a mutation in the methylenetetrahydrofolate reductase gene, is an independent risk factor of coronary artery disease.