Gabriel Miltenberger-Miltenyi

Atomic Force Microscopy-Based Molecular Recognition of a Fibrinogen Receptor on Human Erythrocytes

The established hypothesis for the increase on erythrocyte aggregation associated with a higher incidence of cardiovascular pathologies is based on an increase on plasma adhesion proteins concentration, particularly fibrinogen. Fibrinogen-induced erythrocyte aggregation has been considered to be caused by its nonspecific binding to erythrocyte membranes. In contrast, platelets are known to have a fibrinogen integrin receptor expressed on the membrane surface (the membrane glycoprotein complex alpha(IIb)beta(3)). We demonstrate, by force spectroscopy measurements using an atomic force microscope (AFM), the existence of a single molecule interaction between fibrinogen and an unknown receptor on the erythrocyte membrane, with a lower but comparable affinity relative to platelet binding (average fibrinogen--erythrocyte and --platelet average (un)binding forces were 79 and 97 pN, respectively). This receptor is not as strongly influenced by calcium and eptifibatide (an alpha(IIb)beta(3) specific inhibitor) as the platelet receptor. However, its inhibition by eptifibatide indicates that it is an alpha(IIb)beta(3)-related integrin. Results obtained for a Glanzmann thrombastenia (a rare hereditary bleeding disease caused by alpha(IIb)beta(3) deficiency) patient show (for the first time) an impaired fibrinogen--erythrocyte binding. Correlation with genetic sequencing data demonstrates that one of the units of the fibrinogen receptor on erythrocytes is a product of the expression of the beta(3) gene, found to be mutated in this patient. This work demonstrates and validates the applicability of AFM-based force spectroscopy as a highly sensitive, rapid and low operation cost nanotool for the diagnostic of genetic mutations resulting in hematological diseases, with an unbiased functional evaluation of their severity.

Sarcomeric hypertrophic cardiomyopathy: Genetic profile in a Portuguese population

BACKGROUND Sarcomeric hypertrophic cardiomyopathy has heterogeneous phenotypic expressions, of which sudden cardiac death is the most feared. A genetic diagnosis is essential to identify subjects at risk in each family. The spectrum of disease-causing mutations in the Portuguese population is unknown. METHODS Seventy-seven unrelated probands with hypertrophic cardiomyopathy were systematically screened for mutations by PCR and sequencing of five sarcomeric genes: MYBPC3, MYH7, TNNT2, TNNI3 and MYL2. Familial cosegregation analysis was performed in most patients. RESULTS Thirty-four different mutations were identified in 41 (53%) index patients, 71% with familial hypertrophic cardiomyopathy. The most frequently involved gene was MYBPC3 (66%) with 22 different mutations (8 novel) in 27 patients, followed by MYH7 (22%), TNNT2 (12%) and TNNI3 (2.6%). In three patients (7%), two mutations were found in MYBPC3 and/or MYH7. Additionally, 276 relatives were screened, leading to the identification of a mean of three other affected relatives for each pedigree with the familial form of the disease. CONCLUSIONS Disease-associated mutations were identified mostly in familial hypertrophic cardiomyopathy, corroborating the idea that rarely studied genes may be implicated in sporadic forms. Private mutations are the rule, MYBPC3 being the most commonly involved gene. Mutations in MYBPC3 and MYH7 accounted for most cases of sarcomere-related disease. Multiple mutations in these genes may occur, which highlights the importance of screening both. The detection of novel mutations strongly suggests that all coding regions should be systematically screened. Genotyping in hypertrophic cardiomyopathy enables a more precise diagnosis of the disease, with implications for risk stratification and genetic counseling.

Pachydermoperiostosis in an African patient caused by a Chinese/Japanese SLCO2A1 mutation—Case report and review of literature

OBJECTIVES Pachydermoperiostosis is a rare clinical entity characterized by skin thickening of the forehead, eyelids, and hands, digital clubbing, and periostosis. Two genes have been associated, HPGD and recently SLCO2A1. We present a detailed clinical and genetic description of an African pachydermoperiostosis patient with a SLCO2A1 mutation. METHODS Standard clinical and laboratory evaluation was carried out. Genetic screening was done with PCR followed by direct sequencing. We discuss the clinical features and known mutations of previously reported cases identified through a PubMed literature review. RESULTS The clinical findings showed special features, including exuberant knee effusions and an extraordinary good response on surgery of the blepharoptosis. We found a splice site mutation in the SLCO2A1 gene in homozygous form: c.940+1G>A. This mutation was previously reported only in 1 Chinese and 3 Japanese cases and was considered as a founder mutation in Japan. Beside our case, only one other patient in the literature carried this mutation in homozygous condition, but with different main clinical symptoms. CONCLUSIONS Our case demonstrates phenotypic heterogeneity of PDP even between homozygous carriers of the same mutation, suggesting further modifiers. Besides, it shows that this rare SLCO2A1 mutation is not exclusively present in East-Asia, but can occur in various ethnicities, with different origin, thus the incidence is probably underestimated.

Gene expression differences in peripheral blood of Parkinson's disease patients with distinct progression profiles.

The prognosis of neurodegenerative disorders is clinically challenging due to the inexistence of established biomarkers for predicting disease progression. Here, we performed an exploratory cross-sectional, case-control study aimed at determining whether gene expression differences in peripheral blood may be used as a signature of Parkinson’s disease (PD) progression, thereby shedding light into potential molecular mechanisms underlying disease development. We compared transcriptional profiles in the blood from 34 PD patients who developed postural instability within ten years with those of 33 patients who did not develop postural instability within this time frame. Our study identified >200 differentially expressed genes between the two groups. The expression of several of the genes identified was previously found deregulated in animal models of PD and in PD patients. Relevant genes were selected for validation by real-time PCR in a subset of patients. The genes validated were linked to nucleic acid metabolism, mitochondria, immune response and intracellular-transport. Interestingly, we also found deregulation of these genes in a dopaminergic cell model of PD, a simple paradigm that can now be used to further dissect the role of these molecular players on dopaminergic cell loss. Altogether, our study provides preliminary evidence that expression changes in specific groups of genes and pathways, detected in peripheral blood samples, may be correlated with differential PD progression. Our exploratory study suggests that peripheral gene expression profiling may prove valuable for assisting in prediction of PD prognosis, and identifies novel culprits possibly involved in dopaminergic cell death. Given the exploratory nature of our study, further investigations using independent, well-characterized cohorts will be essential in order to validate our candidates as predictors of PD prognosis and to definitively confirm the value of gene expression analysis in aiding patient stratification and therapeutic intervention.

Chorea‐acanthocytosis presenting as motor neuron disease

Introduction: Chorea‐acanthocytosis (ChAc) is a rare autosomal recessive disease characterized by involuntary movements, seizures, cognitive changes, myopathy, and axonal neuropathy. Methods: We report a patient who presented with gait impairment and dysarthria. Clinical and neurophysiological assessment disclosed upper and lower motor neuron signs suggestive of motor neuron disease (MND). Results: Later observation of involuntary movements prompted further investigation. Acanthocytes were identified, and the patients chorein level was low. Genetic studies identified a novel double heterozygous mutation of the chorein gene involving an exon‐stop mutation associated with another mutation that can affect the normal splicing of the RNA. Conclusions: We speculate that this genetic mutation could cause the atypical presentation. ChAc should be included in the differential diagnosis of atypical MND. Muscle Nerve, 2012

Genetic polymorphisms of proangiogenic factors seem to favor hepatocellular carcinoma development in alcoholic cirrhosis.

Objective Angiogenesis has been associated with hepatic cirrhosis and hepatocellular carcinoma (HCC). Alcohol promotes liver hypoxia, a trigger of angiogenesis. We aimed to evaluate whether the frequency of three polymorphisms in hypoxia-induced factor-1&agr; (HIF-1&agr;), vascular endothelial growth factor A (VEGFA), and KDR (encoding vascular endothelial growth factor receptor 2) genes was higher in alcoholics presenting liver disease (ALD) and ALD patients who developed HCC. Materials and methods Functional HIF-1&agr; 1744C/T, VEGFA 2578C/A, and KDR 1416A/T single-nucleotide polymorphisms were studied in 125 ALD patients and 88 heavy drinkers without liver disease (NLD). ALD patients were followed up to 9 years or until they died; 26 patients developed HCC. Results ALD patients were older than NLD (56±11 vs. 50±13, P<0.001), but drank less (215±164 vs. 331±293 g/day, P<0.001). No differences were found between HIF-1&agr;, VEGFA, or KDR allelic frequencies or genotypes, isolated or simultaneously, between ALD and NLD. In ALD patients, those who developed HCC had a higher KDR 1416T allele frequency (36 vs. 15%, P=0.004; odds ratio 2.72; 95% confidence interval 1.35–5.46). There was also a progressive increase in genotypes with one or two T alleles in patients who developed HCC: AA 50 vs. 73%, AT 35 vs. 23%, and TT 15 vs. 4% (P=0.009). The simultaneous presence of KDR 1416T and VEGFA 2578A was associated with an increased risk of HCC (odds ratio 3.088; 95% confidence interval 1.20–7.96). Conclusion Genetic polymorphisms in proangiogenic factors did not associate with the risk of ALD in heavy drinkers. However, KDR and VEFGA polymorphisms may confer an increased risk of HCC in patients with ALD.

Hypertrophic cardiomyopathy or non-compaction? How the first impression can be wrong

Left ventricular non-compaction cardiomyopathy (LVNC) is a rare disease, resulting from the interruption of myocardial compaction during embryonic growth. Clinical signs are variable, ranging from lack of symptoms to severe manifestations, as heart failure, thromboembolic events, arrhythmias or sudden cardiac death. LVNC is not uncommonly misdiagnosed and, in this regard, multimodality cardiovascular imaging may add important diagnostic information. We report the case of a 46-year-old African black man with no previous significant cardiovascular history, who presented to the emergency department with chest pain, increased cardiac troponin I (31.2 ng/dL) and the ECG showed T wave inversion in lateral and inferior leads, being admitted for non-ST elevation acute myocardial infarction (AMI). Two-dimensional echocardiography performed in the emergency setting showed wall motion abnormalities with posterior akinesia and lateral wall hypokinesia. Non-obstructive assymetric septal and apical hypertrophy was noted in 4-chamber (Fig. 1-A) and parasternal long axis (Fig. 1-B) views. An early invasive strategy was pursued and coronary angiography showed normal coronary arteries. Cardiac magnetic resonance (CMR) was subsequently performed with a presumptive diagnosis of hypertrophic cardiomyopathy (HCM). Surprisingly no left ventricular hypertrophy was demonstrated, but a hypertrabeculated pattern with deep recesses in the left ventricular apical wall, meeting LVNC criteria (ratio between the

Cleidocranial dysplasia with severe parietal bone dysplasia: a new (p.Val124Serfs) RUNX2 mutation.

Neonatal Unit, Genetics Unit, Department of Pediatrics, Santa Maria Hospital and GenoMed Diagnostic Laboratory, Institute of Molecular Medicine, University of Lisbon, Lisbon, Portugal Correspondence to Dr Graça Oliveira, MD, Department of Paediatrics, Santa Maria Hospital, Av. Prof. Egas Moniz, Lisbon 1600, Portugal Tel: + 35 196 928 0518; fax: + 35 121 780 5586; e-mail: graca.oliveira@hsm.min-saude.pt; oligraca@hotmail.co

Novel mutation in the KCNH2 gene associated with long QT syndrome

A 37-year-old man was admitted to our department after an episode of rapid regular palpitations, triggered by emotional stress. He had no previous symptoms and was not taking any medication. There was no relevant family history. The first two electrocardiograms documented sinus rhythm and a pattern of abnormal repolarization with STsegment elevation. The corrected QT interval (QTc) was between 428 and 468 ms (Figure 1A and B). Laboratory tests showed no abnormalities and exercise testing was normal. Holter monitoring documented intermittent QTc prolongation (maximum 580 ms), with no other abnormalities. Screening for mutations in the KCNQ1, KCNH2, SCN5A and KCNE1 genes for LQT1, LQT2, LQT3 and LQT5 variants of long QT syndrome (LQTS) revealed a c.529G>T (p.Glu177X) mutation in heterozygosity in the KCNH2 gene of LQT2

Nova mutação na síndroma de QT Longo em doente com diagnóstico prévio de epilepsia

Congenital long QT syndrome (LQTS) can present as syncope or seizures, secondary to polymorphic ventricular tachycardia, mimicking a primary seizure disorder. In patients treated with an implantable cardioverter-defibrillator (ICD), the recurrence of arrhythmias with subsequent frequent therapeutic shocks may cause adverse reactions, which can be psychogenic. We report the case of a 22-year-old woman with syncope and seizures who was diagnosed in childhood as epileptic and in whom LQTS was diagnosed only in adulthood. Beta-blocker therapy failed and an ICD was implanted. However, as arrhythmias persisted, left cardiac sympathetic denervation was performed. After surgery, three-month follow-up showed a significant reduction in arrhythmias. The genetic study identified a heterozygous mutation, c.1817 C>T p.S606F, on the KCNH2 gene that has not previously been reported in the literature. We also report the rare occurrence of an electrical storm in the course of H1N1 infection. This case illustrates the difficulties in the diagnosis and treatment of LQTS. The possibility of a common genetic basis for arrhythmic diseases and epilepsy is discussed.