Circulation: Cardiovascular Genetics.
2011; 4: 110-122
Targeted Next-Generation Sequencing for the Molecular Genetic Diagnostics of Cardiomyopathies
Benjamin Meder, MD*, Jan Haas, MS*, Andreas Keller, PhD, Christiane Heid, MS, Steffen Just, PhD, Anne Borries, MS, Valesca Boisguerin, PhD, Maren Scharfenberger-Schmeer, PhD, Peer Stähler;, Markus Beier, PhD, Dieter Weichenhan, PhD, Tim M. Strom, MD, Arne Pfeufer, MD, PhD, Bernhard Korn, PhD, Hugo A. Katus, MD and Wolfgang Rottbauer, MD
+ Author Affiliations
From the Department of Internal Medicine III (B.M., J.H., C.H., S.J., H.A.K., W.R.), University of Heidelberg; Biomarker Discovery Center (A.K.); febit biomed gmbh (A.B., V.B., P.S., M.B.); and German Cancer Research Center (DKFZ) (M.S.-S., D.W., B.K.), Heidelberg, Germany; Institute of Human Genetics (T.M.S.), Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany; Institute of Human Genetics (A.P.), Klinikum rechts der Isar, Technische Universität München, Munich, Germany; and Department of Internal Medicine II (W.R.), University of Ulm, Ulm, Germany.
Abstract
Background— Today, mutations in more than 30 different genes have been found to cause inherited cardiomyopathies, some associated with very poor prognosis. However, because of the genetic heterogeneity and limitations in throughput and scalability of current diagnostic tools up until now, it is hardly possible to genetically characterize patients with cardiomyopathy in a fast, comprehensive, and cost-efficient manner.
Methods and Results— We established an array-based subgenomic enrichment followed by next-generation sequencing to detect mutations in patients with hypertrophic cardiomyopathy (HCM) and dilated cardiomyopathy (DCM). With this approach, we show that the genomic region of interest can be enriched by a mean factor of 2169 compared with the coverage of the whole genome, resulting in high sequence coverage of selected disease genes and allowing us to define the genetic pathogenesis of cardiomyopathies in a single sequencing run. In 6 patients, we detected disease-causing mutations, 2 microdeletions, and 4 point mutations. Furthermore, we identified several novel nonsynonymous variants, which are predicted to be harmful, and hence, might be potential disease mutations or modifiers for DCM or HCM.
Conclusions— The approach presented here allows for the first time a comprehensive genetic screening in patients with hereditary DCM or HCM in a fast and cost-efficient manner.
Showing posts with label Genetics. Show all posts
Showing posts with label Genetics. Show all posts
Tuesday, April 19, 2011
Wednesday, February 16, 2011
Hypertension with Dexmedetomidine
Genetic Variations in the α2A-Adrenoreceptor Are Associated with Blood Pressure Response to the Agonist Dexmedetomidine
Daniel Kurnik et al.
CIRC GENETICS.110.957662 Published online before print February 15, 2011
Background—α2A-Adrenoceptors (α2AA-ARs) have important roles in sympathetic cardiovascular regulation. Variants of ADRA2A affect gene transcription and expression and are associated with insulin release and risk for type 2 diabetes. We examined whether ADRA2A variants are also associated with cardiovascular responses to the selective α2-AR-agonist, dexmedetomidine.
Methods and Results—73 healthy subjects participated in a placebo-controlled single-blind study. After 3 infusions of placebo, subjects received 3 incremental infusions of dexmedetomidine (cumulative dose, 0.4 mcg/kg). Primary outcomes were changes in systolic blood pressure (SBP) and plasma norepinephrine concentrations, measured as difference of the area-under-the-curve during placebo and dexmedetomidine infusions (ΔAUC). We used multiple linear regression analysis to examine the associations between 9 ADRA2A tagging variants and 5 inferred haplotypes and ΔAUC after adjustment for covariates. Homozygous carriers of rs553668, and the corresponding haplotype 4, previously associated with increased α2A-AR expression, had a 2.2-fold greater decrease in AUCSBP after dexmedetomidine (adjusted P=0.006); similarly, the maximum decrease in SBP was 24.7±8.1 mmHg compared to 13.6±5.9 mmHg in carriers of the wildtype allele (P=0.007). Carriers of haplotype 3, previously associated with reduced α2A-AR expression, had a 44% smaller decrease in AUCSBP (P=0.013). Haplotype information significantly improved the model predicting the decrease in SBP (P<0.001). There were similar but non-significant trends for diastolic blood pressure and heart rate. Genotypes were not significantly associated with norepinephrine responses.
Conclusions—Common ADRA2A variants are associated with the hypotensive response to dexmedetomidine. Effects of specific variants/haplotypes in vivo are compatible with their known effects on gene expression in vitro.
Daniel Kurnik et al.
CIRC GENETICS.110.957662 Published online before print February 15, 2011
Background—α2A-Adrenoceptors (α2AA-ARs) have important roles in sympathetic cardiovascular regulation. Variants of ADRA2A affect gene transcription and expression and are associated with insulin release and risk for type 2 diabetes. We examined whether ADRA2A variants are also associated with cardiovascular responses to the selective α2-AR-agonist, dexmedetomidine.
Methods and Results—73 healthy subjects participated in a placebo-controlled single-blind study. After 3 infusions of placebo, subjects received 3 incremental infusions of dexmedetomidine (cumulative dose, 0.4 mcg/kg). Primary outcomes were changes in systolic blood pressure (SBP) and plasma norepinephrine concentrations, measured as difference of the area-under-the-curve during placebo and dexmedetomidine infusions (ΔAUC). We used multiple linear regression analysis to examine the associations between 9 ADRA2A tagging variants and 5 inferred haplotypes and ΔAUC after adjustment for covariates. Homozygous carriers of rs553668, and the corresponding haplotype 4, previously associated with increased α2A-AR expression, had a 2.2-fold greater decrease in AUCSBP after dexmedetomidine (adjusted P=0.006); similarly, the maximum decrease in SBP was 24.7±8.1 mmHg compared to 13.6±5.9 mmHg in carriers of the wildtype allele (P=0.007). Carriers of haplotype 3, previously associated with reduced α2A-AR expression, had a 44% smaller decrease in AUCSBP (P=0.013). Haplotype information significantly improved the model predicting the decrease in SBP (P<0.001). There were similar but non-significant trends for diastolic blood pressure and heart rate. Genotypes were not significantly associated with norepinephrine responses.
Conclusions—Common ADRA2A variants are associated with the hypotensive response to dexmedetomidine. Effects of specific variants/haplotypes in vivo are compatible with their known effects on gene expression in vitro.
Wednesday, February 9, 2011
Marfans Syndrome: Revised Ghent Criteria 2010
J Med Genet 2010;47:476-485
The revised Ghent nosology for the Marfan syndrome
Bart L. Loeys et al.
Abstract
The diagnosis of Marfan syndrome (MFS) relies on defined clinical criteria (Ghent nosology), outlined by international expert opinion to facilitate accurate recognition of this genetic aneurysm syndrome and to improve patient management and counselling. These Ghent criteria, comprising a set of major and minor manifestations in different body systems, have proven to work well since with improving molecular techniques, confirmation of the diagnosis is possible in over 95% of patients. However, concerns with the current nosology are that some of the diagnostic criteria have not been sufficiently validated, are not applicable in children or necessitate expensive and specialised investigations. The recognition of variable clinical expression and the recently extended differential diagnosis further confound accurate diagnostic decision making. Moreover, the diagnosis of MFS—whether or not established correctly—can be stigmatising, hamper career aspirations, restrict life insurance opportunities, and cause psychosocial burden. An international expert panel has established a revised Ghent nosology, which puts more weight on the cardiovascular manifestations and in which aortic root aneurysm and ectopia lentis are the cardinal clinical features. In the absence of any family history, the presence of these two manifestations is sufficient for the unequivocal diagnosis of MFS. In absence of either of these two, the presence of a bonafide FBN1 mutation or a combination of systemic manifestations is required. For the latter a new scoring system has been designed. In this revised nosology, FBN1 testing, although not mandatory, has greater weight in the diagnostic assessment. Special considerations are given to the diagnosis of MFS in children and alternative diagnoses in adults. We anticipate that these new guidelines may delay a definitive diagnosis of MFS but will decrease the risk of premature or misdiagnosis and facilitate worldwide discussion of risk and follow-up/management guidelines.
The revised Ghent nosology for the Marfan syndrome
Bart L. Loeys et al.
Abstract
The diagnosis of Marfan syndrome (MFS) relies on defined clinical criteria (Ghent nosology), outlined by international expert opinion to facilitate accurate recognition of this genetic aneurysm syndrome and to improve patient management and counselling. These Ghent criteria, comprising a set of major and minor manifestations in different body systems, have proven to work well since with improving molecular techniques, confirmation of the diagnosis is possible in over 95% of patients. However, concerns with the current nosology are that some of the diagnostic criteria have not been sufficiently validated, are not applicable in children or necessitate expensive and specialised investigations. The recognition of variable clinical expression and the recently extended differential diagnosis further confound accurate diagnostic decision making. Moreover, the diagnosis of MFS—whether or not established correctly—can be stigmatising, hamper career aspirations, restrict life insurance opportunities, and cause psychosocial burden. An international expert panel has established a revised Ghent nosology, which puts more weight on the cardiovascular manifestations and in which aortic root aneurysm and ectopia lentis are the cardinal clinical features. In the absence of any family history, the presence of these two manifestations is sufficient for the unequivocal diagnosis of MFS. In absence of either of these two, the presence of a bonafide FBN1 mutation or a combination of systemic manifestations is required. For the latter a new scoring system has been designed. In this revised nosology, FBN1 testing, although not mandatory, has greater weight in the diagnostic assessment. Special considerations are given to the diagnosis of MFS in children and alternative diagnoses in adults. We anticipate that these new guidelines may delay a definitive diagnosis of MFS but will decrease the risk of premature or misdiagnosis and facilitate worldwide discussion of risk and follow-up/management guidelines.
Tuesday, February 8, 2011
Genetics Primer for Primary Cardiologist
Circulation. 2011;123:544-550
Genetics Primer for the General Cardiologist. Impact of Genetic Insights Into Mendelian Disease on Cardiovascular Clinical Practice
Luke Kim, MD; Richard B. Devereux, MD; Craig T. Basson, MD, PhD
An extract of the first 250 words of the full text is provided, because this article has no abstract.
Introduction: Recent advances in the field of genetics have significantly enhanced our understanding of many cardiovascular conditions and improved diagnosis as well as management of these disorders. However, mendelian cardiovascular diseases still pose unique challenges to clinicians, especially when presented with inherited conditions that have a wide range of phenotypic presentations. In cardiovascular single-gene disorders with potentially devastating initial manifestations, such as sudden cardiac death (SCD) or aortic dissection, appropriate and prompt identification of individuals at risk is imperative. In addition, the management of the disease is not only applicable to the individuals at risk but also extends to other members in the family. Therefore, the general approach to patients with such diseases and their affected family members needs to be considered in the context of fundamental principles of mendelian inheritance. Numerous examples of cardiovascular mendelian disorders exist in which the importance of genetics has been clearly recognized, and most common monogenic cardiovascular disorders are transmitted in families in an autosomal dominant fashion. In such autosomal dominant disorders, it is important to remember the overriding principle that any first-degree relative of an individual with an autosomal dominant multigenerational familial cardiovascular disorder has a 50% chance of also being affected by this genetic trait. Thus, when added to a family history, any symptom or sign on history, clinical evaluation, or testing that is consistent with the diagnosis in question creates a >50% likelihood that the family member is affected by the disorder as well. In this review, we will focus on a . . . [Full Text of this Article]
Genetics Primer for the General Cardiologist. Impact of Genetic Insights Into Mendelian Disease on Cardiovascular Clinical Practice
Luke Kim, MD; Richard B. Devereux, MD; Craig T. Basson, MD, PhD
An extract of the first 250 words of the full text is provided, because this article has no abstract.
Introduction: Recent advances in the field of genetics have significantly enhanced our understanding of many cardiovascular conditions and improved diagnosis as well as management of these disorders. However, mendelian cardiovascular diseases still pose unique challenges to clinicians, especially when presented with inherited conditions that have a wide range of phenotypic presentations. In cardiovascular single-gene disorders with potentially devastating initial manifestations, such as sudden cardiac death (SCD) or aortic dissection, appropriate and prompt identification of individuals at risk is imperative. In addition, the management of the disease is not only applicable to the individuals at risk but also extends to other members in the family. Therefore, the general approach to patients with such diseases and their affected family members needs to be considered in the context of fundamental principles of mendelian inheritance. Numerous examples of cardiovascular mendelian disorders exist in which the importance of genetics has been clearly recognized, and most common monogenic cardiovascular disorders are transmitted in families in an autosomal dominant fashion. In such autosomal dominant disorders, it is important to remember the overriding principle that any first-degree relative of an individual with an autosomal dominant multigenerational familial cardiovascular disorder has a 50% chance of also being affected by this genetic trait. Thus, when added to a family history, any symptom or sign on history, clinical evaluation, or testing that is consistent with the diagnosis in question creates a >50% likelihood that the family member is affected by the disorder as well. In this review, we will focus on a . . . [Full Text of this Article]
Tuesday, December 7, 2010
22q11 microdeletion
requency of 22q11.2 microdeletion in children with congenital heart defects in Western Poland
Anna Wozniak 
, Danuta Wolnik-Brzozowska , Marzena Wisniewska , Renata Glazar , Anna Materna-Kiryluk , Tomasz Moszura , Magdalena Badura-Stronka , Joanna Skolozdrzy , Maciej Krawczynski , Joanna Zeyland , Waldemar Bobkowski , Ryszard Slomski , Anna Latos-Bielenska and Aldona Siwinska
BMC Pediatrics 2010, 10:88doi:10.1186/1471-2431-10-88
| Published: | 6 December 2010 |
Abstract (provisional)
Background
The 22q11.2 microdeletion syndrome (22q11.2 deletion syndrome -22q11.2DS) refers to congenital abnormalities, including primarily heart defects and facial dysmorphy, thymic hypoplasia, cleft palate and hypocalcaemia. Microdeletion within chromosomal region 22q11.2 constitutes the molecular basis of this syndrome. The 22q11.2 microdeletion syndrome occurs in 1/4000 births. The aim of this study was to determine the frequency of 22q11.2 microdeletion in 87 children suffering from a congenital heart defect (conotruncal or non-conotruncal) coexisting with at least one additional 22q11.2DS feature and to carry out 22q11.2 microdeletion testing of the deleted children's parents. We also attempted to identify the most frequent heart defects in both groups and phenotypic traits of patients with microdeletion to determine selection criteria for at risk patients.
Methods
The analysis of microdeletions was conducted using fluorescence in situ hybridization (FISH) on metaphase chromosomes and interphase nuclei isolated from venous peripheral blood cultures. A molecular probe (Tuple) specific to the HIRA (TUPLE1, DGCR1) region at 22q11 was used for the hybridisation.
Results
Microdeletions of 22q11.2 region were detected in 13 children with a congenital heart defect (14.94% of the examined group). Microdeletion of 22q11.2 occurred in 20% and 11.54% of the conotruncal and non-conotruncal groups respectively. Tetralogy of Fallot was the most frequent heart defect in the first group of children with 22q11.2 microdeletion, while ventricular septal defect and atrial septal defect/ventricular septal defect were most frequent in the second group. The microdeletion was also detected in one of the parents of the deleted child (6.25%) without congenital heart defect, but with slight dysmorphism. In the remaining children, 22q11.2 microdeletion originated de novo.
Conclusions
Patients with 22q11.2DS exhibit wide spectrum of phenotypic characteristics, ranging from discreet to quite strong. The deletion was inherited by one child. Our study suggests that screening for 22q11.2 microdeletion should be performed in children with conotruncal and non-conotruncal heart defects and with at least one typical feature of 22q11.2DS as well as in the deleted children's parents.
Monday, September 27, 2010
Trisomy-13 and 18 - Cardiac Surgery
Effectiveness of Cardiac Surgery in Trisomies 13 and 18 (From the Pediatric Cardiac Care Consortium).
Eric Graham, Scott Bradley, Girish Shirali, Christine Hills and Andrew Atz.
Am J Cardiol 2004;93:801-3
1982-2000.
Multicenter Pediatric Cardiac Care Consortium - Cardiac Registry
70 were identified, only 35 had genetic confirmation.
Study group: n=35
5 cardiac diagnostic categories (based on the most-significant lesion):
VSD - 20
TOF - 6
Coarctation - 4
PDA - 3
AVSD - 2.
Weight range: 2.1 - 16 kg (Median 3.7 kg).
Gender: 14/21
Age at surgery: 4 - 2479 days (Median 128 days)
Hospital stay: 3 - 48 days (Median 10 days)
Hospital survival: 32 (91%)
Morbidity: Among 26 patients who were either intubated for surgery or intubated for less than 2 days prior to surgery: Among 9 patients who were intubated for > 2 days prior to surgery, 3 were extubated prior to discharge. One died. 5 were still intubated at discharge.
Follow-up: None, after hospital discharge.
Justification for surgery: To improve quality of life...was not addressed in this study.
Other references:
Japan: Am J Med Genet 2008;146A(11):1372-80 (& Editorial on p.1369-71)
Gp A - 2000-2: Offered no treatment (n=13)
Gp B - 2002-3: Offered pharmacologic treatment for PDA only (n-9)
Gp C - After Nov 2003 - 2005: Pharmacologic and Surgical treatment offered (n=9)
Median length of survival:
Gp A - 7 days
Eric Graham, Scott Bradley, Girish Shirali, Christine Hills and Andrew Atz.
Am J Cardiol 2004;93:801-3
1982-2000.
Multicenter Pediatric Cardiac Care Consortium - Cardiac Registry
70 were identified, only 35 had genetic confirmation.
Study group: n=35
5 cardiac diagnostic categories (based on the most-significant lesion):
VSD - 20
TOF - 6
Coarctation - 4
PDA - 3
AVSD - 2.
Weight range: 2.1 - 16 kg (Median 3.7 kg).
Gender: 14/21
Age at surgery: 4 - 2479 days (Median 128 days)
Hospital stay: 3 - 48 days (Median 10 days)
Hospital survival: 32 (91%)
Morbidity: Among 26 patients who were either intubated for surgery or intubated for less than 2 days prior to surgery: Among 9 patients who were intubated for > 2 days prior to surgery, 3 were extubated prior to discharge. One died. 5 were still intubated at discharge.
Follow-up: None, after hospital discharge.
Justification for surgery: To improve quality of life...was not addressed in this study.
Other references:
Japan: Am J Med Genet 2008;146A(11):1372-80 (& Editorial on p.1369-71)
Gp A - 2000-2: Offered no treatment (n=13)
Gp B - 2002-3: Offered pharmacologic treatment for PDA only (n-9)
Gp C - After Nov 2003 - 2005: Pharmacologic and Surgical treatment offered (n=9)
Median length of survival:
Gp A - 7 days
Gp B - 24 days
Gp C - 243 days
Utah: Am J Med Genet 2006;140:937-44 & 1994;49:175-88Saturday, July 10, 2010
Warfarin - Genotyping
Warfarin genotyping reduces hospitalization rates. Results from MM-WES (Medco-Mayo Warfarin Effectiveness Study).
Robert S. Epstein, et al. JACC 2010;55(25):2804-12.
Article
Editorial comments
Two genes have been shown in past decade to influence warfarin dosing.
One gene, CYP2C9 determines the activity of hepatic isoenzyme cytochrome P450 2C9 that plays a role in converting S-war-farin to its inactive form.
Second gene, VKORC1 - determines the activity of Vit K epoxide reductase that produces the active form of Vit K that is necessary for clotting.
CYP 2C9 & NKORC1 polymorphisms account for > 1/3rd of variations associated with variations in warfarin dosage. Warfarin sensitivity genotyping involves a test that simultaneously tests for allelic variation in both genes.
Genetic testing is not widely adopted due to lack of studies demonstrating the utility of these tests. This is the first national study on this.
Robert S. Epstein, et al. JACC 2010;55(25):2804-12.
Article
Editorial comments
Two genes have been shown in past decade to influence warfarin dosing.
One gene, CYP2C9 determines the activity of hepatic isoenzyme cytochrome P450 2C9 that plays a role in converting S-war-farin to its inactive form.
Second gene, VKORC1 - determines the activity of Vit K epoxide reductase that produces the active form of Vit K that is necessary for clotting.
CYP 2C9 & NKORC1 polymorphisms account for > 1/3rd of variations associated with variations in warfarin dosage. Warfarin sensitivity genotyping involves a test that simultaneously tests for allelic variation in both genes.
Genetic testing is not widely adopted due to lack of studies demonstrating the utility of these tests. This is the first national study on this.
Thursday, July 8, 2010
Genetics: Genome Wide Association Studies - Review from NEJM
Article reviews the principles of the procedure and its implications.
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