Zurich Fabry study - prevalence of Fabry disease in young patients with first cryptogenic ischaemic stroke or TIA.

BACKGROUND AND PURPOSE: The etiology of stroke in young patients remains undetermined in up to half of the cases. Data on prevalence of Fabry disease (FD) in young people with cryptogenic ischaemic stroke are limited and controversial. We aimed to evaluate the frequency of unrecognized FD in a cohort of stroke patients at a tertiary stroke center. METHODS: Patients suffering from first cryptogenic ischaemic stroke or transient ischaemic attack (TIA) at the age of 18-55 years were screened for the presence of FD. We measured the serum activity of α-galactosidase (α-GAL) in all patients. In addition, sequencing of α-GAL gene was performed in men with low enzyme activity and in all women. RESULTS: Between January, 2006, and October, 2009, we recruited 150 patients (102 men, 48 women) with a mean age of 43 ± 9 years at symptom onset (135 ischaemic stroke, 15 TIA). The α-GAL activity was low in nine patients (6%; six men and three women). Genetic sequencing in six men with low enzyme activity and all 48 women detected no α-GAL gene mutation. CONCLUSION: Our study suggests that the yield of screening for FD in patients with first cryptogenic ischaemic stroke or TIA is very low. Further large-scale studies are needed to investigate the importance of FD amongst patients with recurrent cryptogenic strokes.

DIAgnosis and Management Of familial hypercholesterolemia in a Nationwide Design (DIAMOND-FH): Prevalence in Switzerland, clinical characteristics and the diagnostic value of clinical scores.

BACKGROUND AND AIMS: In Switzerland, the prevalence of familial hypercholesterolemia (FH) due to pathogenic apolipoprotein B-100 gene (APOB) variants was known, but not the prevalence of FH due to pathogenic low-density lipoprotein-receptor gene (LDLR) variants. Phenotypic differences (LDLR versus APOB) might affect the diagnostic value of the Dutch Lipid Clinic Network (DLCN) score and Simon Broome Diagnostic Criteria (SBDC). METHODS: A total of 2734 Swiss subjects were investigated, 2221 unselected subjects from three representative population surveys for estimation of the prevalence (LDLR variants), and 513 subjects from the DIAgnosis and Management Of familial hypercholesterolemia in a Nationwide Design (DIAMOND-FH) study for comparisons of phenotypic characteristics (LDLRversusAPOB variants), diagnostic values of clinical scores, and cardiovascular outcome. RESULTS: In 7 of 2221 individuals, FH (LDLR) was diagnosed (prevalence of FH due to LDLR variants: 1/317, prevalence of FH due to both LDLR and APOB variants: 1/125 to 1/135). In FH (APOB) patients under 35 years of age, mean total cholesterol (TC) was <8.5 mmoL/L but increased above 35. In FH (LDLR), TC was >8.5 mmoL/L in all age groups. This difference was crucial for the diagnosis of FH and resulted in a significantly lower sensitivity of clinical scores in FH (APOB) (DLCN: 13.8%, p < 0.0001; SBDC: 22.5%, p = 0.005). Thus, both scores were not useful for the definite diagnosis of FH due to APOB variants. Regarding the cardiovascular outcome, no differences (LDLR versus APOB) were found above 60 years. In countries with high percentages of FH due to APOB variants, cascade screening and molecular testing appear to be much more cost-effective.

The discrete and combined effect of SREBP-2 and SCAP isoforms in the control of plasma lipids among familial hypercholesterolaemia patients.

BACKGROUND AND AIM: Hypercholesterolaemia is a major risk factor for atherosclerosis. Cholesterol is modulated by genetic and environmental factors. An important regulatory pathway is controlled by the sterol-regulatory element-binding proteins (SREBPs) and the SREBP cleavage-activating protein (SCAP). Both SREBP-2 and SCAP are candidates to contribute to the development of atherosclerosis. We investigated the possible effects of the variability of proteins involved in this regulatory pathway on plasma lipids among familial hypercholesterolaemia patients. METHODS AND RESULTS: Single nucleotide polymorphisms (SNPs) in the genes encoding SREBP-2 and SCAP causing amino acid changes at positions 595 (595G/A) and 796 (796I/V), respectively, were genotyped in 801 FH individuals originating from Israel, The Netherlands, and Switzerland. A linear regression model to examine the associations between SREBP-2 and SCAP isoforms and lipid and lipoprotein levels was used. In females, homozygosity either for the SREBP-2-595A or for the SCAP-796I isoform was associated with higher LDL-cholesterol plasma concentrations (14.7 mg/dl and 20.3 mg/dl, respectively). Surprisingly, heterozygosity for the combination SREBP-2-595A/SCAP-796I was associated with a decrease of 30.28 mg/dl in LDL-C (p-value for gene-gene interaction=0.09). No such effect was observed among FH males. Subgroup analysis considering the most frequent (N>/=24) LDL receptor mutations (del191-2, ins313+1-2, C660X, E207K, S285L) revealed further gene-dosage- and gender-dependent effects of the SCAP mutations on LDL-cholesterol concentrations (p=0.0345). These effects were, however, not present when less frequent LDL receptor mutations were investigated. CONCLUSIONS: These results suggest a possible gene-gene interaction between the genes encoding SREBP-2 and SCAP that modulate plasma lipids in a strictly gender-specific fashion. Further investigation is needed to confirm this effect. A study in a larger FH group or in non-FH hypercholesterolaemic subjects may further define the role of this regulatory mechanism in determining plasma lipid concentration.

Identification of mutations in the gene encoding sterol regulatory element binding protein (SREBP)-2 in hypercholesterolaemic subjects.

Human cells maintain their cholesterol homeostasis by regulated cleavage of membrane bound transcription factors, so-called sterol regulatory element binding proteins (SREBPs). If cells are deprived of cholesterol, SREBPs are cleaved by two proteolytic steps. The NH2-terminal domain of the SREBPs is released from the membranes of the endoplasmic reticulum and transported into the nucleus, where it binds to specific nucleotide sequences in the promoters of the low density lipoprotein receptor gene and of key genes involved in cholesterol and triglyceride homeostasis. Given the central role of SREBPs in the regulation of cholesterol metabolism, we investigated whether subjects with inherited forms of high plasma cholesterol carry specific sequence variations in SREBP-2 that might be involved in the development of hypercholesterolaemia. Exons 5 to 10, encoding the DNA binding and the regulatory domains of SREBP-2, were screened for sequence variations in a cohort of 70 hypercholesterolaemic subjects. Two missense mutations (V623M, R645Q) in the regulatory domain, one single nucleotide polymorphism (R371K) in the DNA binding domain, and one translationally silent mutation (P433P) were identified in SREBP-2. However, none of the mutations found in the regulatory domain could be detected in 167 subjects of a random control sample. A potential causative mechanism of these mutations for high plasma cholesterol concentrations is discussed. In summary, this is the first report of mutations in the human SREBP-2 gene to suggest that these and/or other mutations in this key regulator of cholesterol metabolism are associated with hypercholesterolaemia.

A single-nucleotide polymorphism in the sterol-regulatory element-binding protein 1c gene is predictive of HIV-related hyperlipoproteinaemia.

A single-nucleotide polymorphism (3'322C/G) was identified in the gene encoding a key cholesterol/triglyceride regulator, sterol-regulatory element-binding protein 1c (SREBP-1c). Although it did not alter the amino acid sequence, SREBP-1c-3'322C/G was predictive of highly active antiretroviral therapy-related hyperlipoproteinaemia. Increases in cholesterol were less frequently associated with homozygous SREBP-1c-3'322G (genotype 22) than with heterozygous/homozygous SREBP-1c-3'322C (genotypes 11/12) and correlated with leptin and insulin increases, particularly in genotype 11/12 carriers. A functional mutation linked to SREBP-1c-3'322C/G or messenger RNA conformation differences may explain our findings.

Estimation of tissue hypothyroidism by a new clinical score: evaluation of patients with various grades of hypothyroidism and controls.

The classical signs and symptoms of hypothyroidism were reevaluated in the light of the modern laboratory tests for thyroid function. We analyzed 332 female subjects: 50 overt hypothyroid patients, 93 with subclinical hypothyroidism (SCH), 67 hypothyroid patients treated with T4, and 189 euthyroid subjects. The clinical score was defined as the sum of the 2 best discriminating signs and symptoms. Beside TSH and thyroid hormones, we measured parameters known to reflect tissue manifestations of hypothyroidism, such as ankle reflex relaxation time and total cholesterol. Classical signs of hypothyroidism were present only in patients with severe overt hypothyroidism with low T3, but were rare or absent in patients with normal T3 but low free T4 or in patients with SCH (normal thyroid hormones but elevated basal TSH; mean scores, 7.8 +/- 2.7 vs. 4.4 +/- 2.2 vs. 3.4 +/- 2.0; P < 0.001). Assessment of euthyroid subjects and T4-treated patients revealed very similar results (mean score, 1.6 +/- 1.6 vs. 2.1 +/- 1.5). In overt hypothyroid patients, the new score showed an excellent correlation with ankle reflex relaxation time and total cholesterol (r = 0.76 and r = 0.60; P < 0.0001), but no correlation with TSH (r = 0.01). The correlation with free T4 was r = -0.52 (P < 0.0004), and that with T3 was r = -0.56 (P < 0.0001). In SCH, the best correlation was found between the new score and free T4 (r = -0.41; P < 0.0001) and TSH (r = 0.35; P < 0.0005). Evaluation of symptoms and signs of hypothyroidism with the new score in addition to thyroid function testing is very useful for the individual assessment of thyroid failure and the monitoring of treatment.

TSH-controlled L-thyroxine therapy reduces cholesterol levels and clinical symptoms in subclinical hypothyroidism: a double blind, placebo-controlled trial (Basel Thyroid Study).

This study evaluated the effect of physiological, TSH-guided, L-thyroxine treatment on serum lipids and clinical symptoms in patients with subclinical hypothyroidism. Sixty-six women with proven subclinical hypothyroidism (TSH, 11.7 +/- 0.8 mIU/liter) were randomly assigned to receive L-thyroxine or placebo for 48 wk. Individual L-thyroxine replacement (mean dose, 85.5 +/- 4.3 microg/d) was performed based on blinded TSH monitoring, resulting in euthyroid TSH levels (3.1 +/- 0.3 mIU/liter). Lipid concentrations and clinical scores were measured before and after treatment. Sixty-three of 66 patients completed the study. In the L-thyroxine group (n = 31) total cholesterol and low density lipoprotein cholesterol were significantly reduced [-0.24 mmol/liter, 3.8% (P = 0.015) and -0.33 mmol/liter, 8.2% (P = 0.004), respectively]. Low density lipoprotein cholesterol decrease was more pronounced in patients with TSH levels greater than 12 mIU/liter or elevated low density lipoprotein cholesterol levels at baseline. A significant decrease in apolipoprotein B-100 concentrations was observed (P = 0.037), whereas high density lipoprotein cholesterol, triglycerides, apolipoprotein AI, and lipoprotein(a) levels remained unchanged. Two clinical scores assessing symptoms and signs of hypothyroidism (Billewicz and Zulewski scores) improved significantly (P = 0.02). This is the first double blind study to show that physiological L-thyroxine replacement in patients with subclinical hypothyroidism has a beneficial effect on low density lipoprotein cholesterol levels and clinical symptoms of hypothyroidism. An important risk reduction of cardiovascular mortality of 9-31% can be estimated from the observed improvement in low density lipoprotein cholesterol.

Genetic association of a cystatin C gene polymorphism with late-onset Alzheimer disease.

OBJECTIVE: To determine whether the cystatin C gene (CST3) is genetically associated with late-onset Alzheimer disease (AD). DESIGN: A case-control study with 2 independent study populations of patients with AD and age-matched, cognitively normal control subjects. SETTING: The Alzheimer's Disease Research Unit at the University Hospital Hamburg-Eppendorf, Hamburg, Germany, for the initial study (n = 260). For the independent multicenter study (n = 647), an international consortium that included the Massachusetts Alzheimer's Disease Research Center at the Massachusetts General Hospital, Boston; the Scientific Institute for Research and Patient Care, Brescia, Italy; and Alzheimer's research units at the Universities of Basel and Zurich, Switzerland, and Bonn, Goettingen, and Hamburg, Germany. PARTICIPANTS: Five hundred seventeen patients with AD and 390 control subjects. MEASURES: Molecular testing of the KspI polymorphisms in the 5' flanking region and exon 1 of CST3 and the apolipoprotein E (APOE) genotype. Mini-Mental State Examination scores for both patients with AD and control subjects. RESULTS: Homozygosity for haplotype B of CST3 was significantly associated with late-onset AD in both study populations, with an odds ratio of 3.8 (95% confidence interval, 1.56-9.25) in the combined data set; heterozygosity was not associated with an increased risk. The odds ratios for CST3 B/B increased from 2.6 in those younger than 75 years to 8.8 for those aged 75 years and older. The association of CST3 B/B with AD was independent of APOE epsilon4; both genotypes independently reduced disease-free survival. CONCLUSIONS: CST3 is a susceptibility gene for late-onset AD, especially in patients aged 75 years and older. To our knowledge, CST3 B is the first autosomal recessive risk allele in late-onset AD.

Clinical value of a mucin-like carcinoma-associated antigen in monitoring breast cancer patients in comparison with CA 15-3.

A new tumour marker, mucin-like carcinoma-associated antigen (MCA), was evaluated in 176 breast cancer patients classified either as free of tumour (NED, n = 141) or as having metastases (PD, n = 35). During the 5 year follow-up, 842 measurements of MCA and 363 measurements of CA 15-3 were done. MCA levels were significantly increased in the PD group (P = 0.0001) but not in the NED group. The sensitivities of the MCA and the CA 15-3 assays were 84% and 78% and the specificities were 81% and 78%, respectively. The negative predictive value of 97% for MCA was significantly higher (P = 0.0001) than the 88% for CA 15-3. Thus the MCA enzyme immunoassay is at least equivalent to the CA 15-3 test and is recommended in the assessment of metastatic spread or tumour recurrence in breast cancer patients.

Molecular Biocomputing Suite: a word processor add-in for the analysis and manipulation of nucleic acid and protein sequence data.

In all fields of molecular biology, researchers are increasingly challenged by experiments planned and evaluated on the basis of nucleic acid and protein sequence data generally retrieved from public databases. Despite the wide spectrum of available Web-based software tools for sequence analysis, the routine use of these tools has disadvantages, particularly because of the elaborate and heterogeneous ways of data input, output, and storage. Here we present a Visual Basic-encoded Microsoft Word Add-In, the Molecular BioComputing Suite (MBCS), available at the BioTechniques Software Library (www.BioTechniques.com). The MBCS software aims to manage and expedite a wide range of sequence analyses and manipulations using an integrated text editor environment including menu-guided commands. Its independence of sequence formats enables MBCS to be used as a pivotal application between other software tools for sequence analysis, manipulation, annotation, and editing.

RepGene: a spreadsheet template for the management of reporter gene assays.

One of the most powerful techniques in molecular biology is the controlled expression of specific proteins by transfection of eukaryotic cells. This method has become feasible and highly sensitive and, thus, suitable for high-throughput reporter gene assays in basic and applied research. Moreover, the limiting factors are neither the transfection efficiency nor the functional analysis, but rather the ability to manage complex experimental protocols when multiple genes are co-transfected and/or when the effects of several chemical compounds are investigated within the same experiment. Here, we describe an easy-to-use and highly flexible spreadsheet template intended to rationalize and expedite the organization and data management of multi-step reporter gene assays. The objectives of this spreadsheet template are the design of the transfection protocol, the coordination of the administration of test compounds, and the graphical presentation and statistical analysis of the results.

Clinical value of a mucin-like carcinoma-associated antigen (MCA) in patients with carcinomas of the kidney and the urinary collecting system.

A new tumor marker, mucin-like carcinoma-associated antigen (MCA), was evaluated in thirty-four patients with renal cell carcinomas and forty patients with carcinomas of the urinary collecting system. In the first group, specificity was 95%, sensitivity 65%, the predictive value for positive diagnosis was 94%, and for negative diagnosis 72%. In the second group specificity was 83%, sensitivity 71%, predictive value for positive diagnosis was 63%, and for negative diagnosis 88%. Receiver operating characteristic curves indicated that the maximum amount of information was greater in patients of the first group than the second (0.379 vs. 0.332 bits). In the light of these data, the MCA test can be recommended for assessing metastatic spread in patients particularly with renal cell carcinomas.

The diagnostic value of mucinous carcinoma-associated antigen (MCA) tests in breast carcinomas.

MCA (Mucinous Carcinoma-Associated Antigen) levels of 176 breast carcinoma patients were tested postoperatively by serial determination. One hundred forty-one patients had non-progressive disease (PD-) while 35 were in the progressive phase (PD+); in the latter the diagnosis was confirmed by means of current diagnostic procedures. One hundred seventeen of the 141 PD-patients showed MCA levels below cutoff whereas 27 of the 35 PD+ cases showed high values. The difference in the incidence of elevated MCA levels between PD- and PD+ groups was statistically significant (p < 0.05). The overall diagnostic efficacy of MCA assays showed 77% sensitivity and 82% specificity.

[Prevention of coronary heart disease in familial hypercholesterolemia]. / Prävention der koronaren Herzkrankheit bei familiären Hypercholesterinämien.

Familial forms of isolated hypercholesterolemia are inherited autosomal-dominantly and are caused by defects of the low-density lipoprotein (LDL) receptor protein or its ligand, the apolipoprotein B-100, the exclusive apolipoprotein moiety of the LDL particles. Mutations at the LDL receptor gene locus (more than 150 different mutations have been described up to now) lead to familial hypercholesterolemia (FH); the only mutation at the apolipoprotein B-100 gene locus described in detail so far leads to the so-called familial defective apolipoprotein B-100 (FDB). Both lipid disorders are characterized by an increased risk for premature atherosclerosis involving primarily the coronary arteries. An increased risk for coronary heart disease can be expressed statistically by the excess mortality. In particular, individuals between the age of 20 and 59 are affected by an excess mortality; coronary deaths are approximately 100 times more frequent in patients between 20 and 39 with familial forms of hypercholesterolemia than within the normal population. On the other hand, in patients with myocardial infarctions before the age of 60, the diagnosis of FH is approximately 20 to 30 times more frequent than within the normal population. A regression of cardiovascular lesions subsequent to an intensive lipid-lowering therapy has clearly been demonstrated in patients with familial forms of hypercholesterolemia. Because of the serious prognosis of untreated familial forms of isolated hypercholesterolemia with respect to longevity, it is important to identify patients and their relatives with FH and FDB as early as possible and to treat them, besides a lipid-lowering diet, intensively with lipid-lowering drugs.

[Application of genetic principles to the causal assessment of atherosclerosis]. / Anwendung genetischer Prinzipien zur Ursachenabklärung der Atherosklerose.

The pathophysiological mechanisms responsible for the development of atherosclerosis are complex and influenced by numerous genetic factors [polygenic] as well as environmental factors. Specific disorders caused by single gene mutations [monogenic] may considerably enhance the risk for atherosclerosis. In such cases, other genes or environmental factors are often secondary importance. A detailed family history including a pedigree analysis may lead to the correct diagnosis; molecular genetic methods can confirm the clinical diagnosis. The association between a particular gene [candidate gene] and a disorder characterized by an increased risk for atherosclerosis can be verified indirectly by linkage analysis or directly by the detection of the gene mutation causing the disorder. Both approaches are based on the fact that a polymorphism used as a marker for a gene locus or a mutation responsible for a particular disorder may destroy or create a restriction site [restriction fragment length polymorphism, RFLP] or may modify the electrophoretic mobility of a fragment amplified by the polymerase chain reaction [PCR]. The latter property is the basis of the single-strand conformation polymorphism [SSCP] technique, followed by sequencing for the exact localization of the polymorphism or the mutation. Using these methods, other family members carrying the underlying gene defect can be identified and treated before the manifestation of their atherosclerotic lesions.

A Novel Study Paradigm for Long-term Prevention Trials in Alzheimer Disease: The Placebo Group Simulation Approach (PGSA): Application to MCI data from the NACC database.

INTRODUCTION: The PGSA (Placebo Group Simulation Approach) aims at avoiding problems of sample representativeness and ethical issues typical of placebo-controlled secondary prevention trials with MCI patients. The PGSA uses mathematical modeling to forecast the distribution of quantified outcomes of MCI patient groups based on their own baseline data established at the outset of clinical trials. These forecasted distributions are then compared with the distribution of actual outcomes observed on candidate treatments, thus substituting for a concomitant placebo group. Here we investigate whether a PGSA algorithm that was developed from the MCI population of ADNI 1*, can reliably simulate the distribution of composite neuropsychological outcomes from a larger, independently selected MCI subject sample. METHODS: Data available from the National Alzheimer's Coordinating Center (NACC) were used. We included 1523 patients with single or multiple domain amnestic mild cognitive impairment (aMCI) and at least two follow-ups after baseline. In order to strengthen the analysis and to verify whether there was a drift over time in the neuropsychological outcomes, the NACC subject sample was split into 3 subsamples of similar size. The previously described PGSA algorithm for the trajectory of a composite neuropsychological test battery (NTB) score was adapted to the test battery used in NACC. Nine demographic, clinical, biological and neuropsychological candidate predictors were included in a mixed model; this model and its error terms were used to simulate trajectories of the adapted NTB. RESULTS: The distributions of empirically observed and simulated data after 1, 2 and 3 years were very similar, with some over-estimation of decline in all 3 subgroups. The by far most important predictor of the NTB trajectories is the baseline NTB score. Other significant predictors are the MMSE baseline score and the interactions of time with ApoE4 and FAQ (functional abilities). These are essentially the same predictors as determined for the original NTB score. CONCLUSION: An algorithm comprising a small number of baseline variables, notably cognitive performance at baseline, forecasts the group trajectory of cognitive decline in subsequent years with high accuracy. The current analysis of 3 independent subgroups of aMCI patients from the NACC database supports the validity of the PGSA longitudinal algorithm for a NTB. Use of the PGSA in long-term secondary AD prevention trials deserves consideration.

Quantitative EEG and apolipoprotein E-genotype improve classification of patients with suspected Alzheimer's disease.

OBJECTIVE: To establish a model for better identification of patients in very early stages of Alzheimer's disease, AD (including patients with amnestic MCI) using high-resolution EEG and genetic data. METHODS: A total of 26 patients in early stages of probable AD and 12 patients with amnestic MCI were included. Both groups were similar in age and education. All patients had a comprehensive neuropsychological examination and a high resolution EEG. Relative band power characteristics were calculated in source space (LORETA inverse solution for spectral data) and compared between groups. A logistic regression model was calculated including relative band-power at the most significant location, ApoE status, age, education and gender. RESULTS: Differences in the delta band at 34 temporo-posterior source locations (p<.01) between AD and MCI groups were detected after correction for multiple comparisons. Classification slightly increased when ApoE status was added (p=.06 maximum likelihood test). Adjustment of analyses for the confounding factors age, gender and education did not alter results. CONCLUSIONS: Quantitative EEG (qEEG) separates between patients with amnestic MCI and patients in early stages of probable AD. Adding information about Apo ε4 allele frequency slightly enhances diagnostic accuracy. SIGNIFICANCE: qEEG may help identifying patients who are candidates for possible benefit from future disease modifying treatments.