title: Risk prediction for clinical phenotype in myotonic dystrophy type 1: data from 2,650 patients.
abstract: Myotonic dystrophy type 1 (DM1) is a multisystem disorder that affects skeletal and smooth muscle as well as the eye, heart, endocrine system, and central nervous system. DM1 is caused by expansion of a CTG trinucleotidedaggerrepeat in the gene DMPK. Clinical findings in DM1 span a continuum from mild to severe. Although the CTG repeat correlates with the disease phenotype, caution is used in predicting disease severity on the basis of CTG repeat number. This study reports an extensive genotype-phenotype study to evaluate the clinical validity and clinical utility of the molecular genetic test. Data were analyzed by multiple logistic regression, used to estimate the odds ratio (OR) and correlation coefficients for patients phenotype in respect to the categorical variables expansion class, gender, familiarity, and the continuous variables age and disease duration. We assessed disease expression by clinical evaluation and the molecular genetic test in 2,650 patients identified by accurate clinical diagnosis and family segregation. We were able to estimate OR and correlation coefficients for patients phenotype according to CTG number. A genotype-phenotype correlation was established to derivate a clinical predictive risk on the basis of molecular data. This study demonstrates that measurement of triplet expansions in patients' DNA can be considered as a useful tool for DM1 phenotype assessment and presymptomatic testing.
authors: Department of Biopathology and Diagnostic Imaging, Tor Vergata University, Rome, Italy. l.b.salehi@mclink.it
authors: Leila Baghernajad
authors: LB
authors: Salehi
authors: Emanuela
authors: E
authors: Bonifazi
authors: Enrico Di
authors: ED
authors: Stasio
authors: Massimo
authors: M
authors: Gennarelli
authors: Annalisa
authors: A
authors: Botta
authors: Laura
authors: L
authors: Vallo
authors: Raniero
authors: R
authors: Iraci
authors: Roberto
authors: R
authors: Massa
authors: Giovanni
authors: G
authors: Antonini
authors: Corrado
authors: C
authors: Angelini
authors: Giuseppe
authors: G
authors: Novelli
mesh_terms: D005838:Genotype; D006801:Humans; D009223:Myotonic Dystrophy / Q000235:genetics* / Q000473:pathology; D010641:Phenotype; D012306:Risk; D018911:Trinucleotide Repeats