title: Toronto hypertrophic cardiomyopathy genotype score for prediction of a positive genotype in hypertrophic cardiomyopathy.
abstract: BACKGROUND
  Genotyping in hypertrophic cardiomyopathy has gained increasing attention in the past decade. Its major role is for family screening and rarely influences decision-making processes in any individual patient. It is associated with substantial costs, and cost-effectiveness can only be achieved in the presence of high-detection rates for disease-causing sarcomere protein gene mutations. Therefore, our aim was to develop a score based on clinical and echocardiographic variables that allows prediction of the probability of a positive genotype.
  
  
  RESULTS
  Clinical and echocardiographic variables were collected in 471 consecutive patients undergoing genetic testing at a tertiary referral center between July 2005 and November 2010. Logistic regression for a positive genotype was used to construct integer risk weights for each independent predictor variable. These were summed for each patient to create the Toronto hypertrophic cardiomyopathy genotype score. A positive genotype was found in 163 of 471 patients (35%). Independent predictors with associated-risk weights in parentheses were as follows: age at diagnosis 20 to 29 (-1), 30 to 39 (-2), 40 to 49 (-3), 50 to 59 (-4), 60 to 69 (-5), 70 to 79 (-6), ≥80 (-7); female sex (4); arterial hypertension (-4); positive family history for hypertrophic cardiomyopathy (6); morphology category (5); ratio of maximal wall thickness:posterior wall thickness <1.46 (0), 1.47 to 1.70 (1), 1.71 to 1.92 (2), 1.93 to 2.26 (3), ≥2.27 (4). The model had a receiver operator curve of 0.80 and Hosmer-Lemeshow goodness-of-fit P=0.22.
  
  
  CONCLUSIONS
  The Toronto genotype score is an accurate tool to predict a positive genotype in a hypertrophic cardiomyopathy cohort at a tertiary referral center.
authors.affiliation: Division of Cardiology, Toronto General Hospital, Peter Munk Cardiac Center, 4N-504, 200 Elizabeth St, Toronto, ON M5G 2C4, Canada. christiane.gruner@gmx.ch
authors.forename: Christiane
authors.initials: C
authors.lastname: Gruner
authors.forename: Joan
authors.initials: J
authors.lastname: Ivanov
authors.forename: Melanie
authors.initials: M
authors.lastname: Care
authors.forename: Lynne
authors.initials: L
authors.lastname: Williams
authors.forename: Gil
authors.initials: G
authors.lastname: Moravsky
authors.forename: Hua
authors.initials: H
authors.lastname: Yang
authors.forename: Balint
authors.initials: B
authors.lastname: Laczay
authors.forename: Katherine
authors.initials: K
authors.lastname: Siminovitch
authors.forename: Anna
authors.initials: A
authors.lastname: Woo
authors.forename: Harry
authors.initials: H
authors.lastname: Rakowski
mesh_terms: D000328:Adult; D000368:Aged; D002312:Cardiomyopathy, Hypertrophic / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000235:genetics*; D015331:Cohort Studies; D004452:Echocardiography; D005260:Female; D005820:Genetic Testing / Q000379:methods*; D005838:Genotype; D006801:Humans; D008297:Male; D008875:Middle Aged; D008957:Models, Genetic; D055815:Young Adult