scholarly journals CAG-repeat length and the age of onset in Huntington disease (HD): A review and validation study of statistical approaches

2009 ◽  
Vol 153B (2) ◽  
pp. 397-408 ◽  
Author(s):  
Douglas R. Langbehn ◽  
Michael R. Hayden ◽  
Jane S. Paulsen ◽  
2020 ◽  
Vol 21 (1) ◽  
Author(s):  
Paula Sienes Bailo ◽  
Raquel Lahoz ◽  
Juan Pelegrín Sánchez Marín ◽  
Silvia Izquierdo Álvarez

Abstract Background Despite the progress in the knowledge of Huntington disease (HD) in recent years, the epidemiology continues uncertain, so the study of incidence becomes relevant. This is important since various factors (type of population, diagnostic criteria, disease-modifying factors, etc.) make these data highly variable. Therefore, the genetic diagnosis of these patients is important, since it unequivocally allows the detection of new cases. Methods Descriptive retrospective study with 179 individuals. Incidence of HD was calculated from the ratio of number of symptomatic cases newly diagnosed per 100,000 inhabitants per year during the period 2007–2019 in Aragon (Spain). Results 50 (27.9%) incident cases of HD (CAG repeat length ≥ 36) were identified from a total of 179 persons studied. The remaining 129/179 (72.1%) were HD negative (CAG repeat length < 36). 29 (58.0%) females and 21 (42.0%) males were confirmed as HD cases. The overall incidence was 0.648 per 100,000 patient-years. 11/50 positive HD cases (22.0%) were identified by performing a predictive test, without clinical symptoms. The minimum number of CAG repeats found was 9 and the most common CAG length among HD negative individuals was 16. Conclusions Our incidence lied within the range reported for other Caucasian populations. Implementation of new techniques has allowed to determine the exact number of CAG repeats, which is especially important in patients with triplet expansions in an HD intermediate and/or incomplete penetrance allele, both in diagnostic, predictive and prenatal tests.


2020 ◽  
Vol 10 (9) ◽  
pp. 575 ◽  
Author(s):  
Jordan L. Schultz ◽  
Amelia D. Moser ◽  
Peg C. Nopoulos

There is a known negative association between cytosine–adenine–guanine (CAG) repeat length and the age of motor onset (AMO) in adult-onset Huntington’s Disease (AOHD). This relationship is less clear in patients with juvenile-onset Huntington’s disease (JOHD), however, given the rarity of this patient population. The aim of this study was to investigate this relationship amongst a relatively large group of patients with JOHD using data from the Kids-JOHD study. Additionally, we analyzed data from the Enroll-HD platform and the Predict-HD study to compare the relationship between CAG repeat length and AMO amongst patients with AOHD to that amongst patients with JOHD using linear regression models. In line with previous reports, the variance in AMO that was predicted by CAG repeat length was 59% (p < 0.0001) in the Predict-HD study and 57% from the Enroll-HD platform (p < 0.0001). However, CAG repeat length predicted 84% of the variance in AMO amongst participants from the Kids-JOHD study (p < 0.0001). These results indicate that there may be a stronger relationship between CAG repeat length and AMO in patients with JOHD as compared to patients with AOHD. These results provide additional information that may help to model disease progression of JOHD, which is beneficial for the planning and implementation of future clinical trials.


Neurology ◽  
2006 ◽  
Vol 66 (7) ◽  
pp. 1016-1020 ◽  
Author(s):  
A. Rosenblatt ◽  
K. -Y. Liang ◽  
H. Zhou ◽  
M. H. Abbott ◽  
L. M. Gourley ◽  
...  

Objective: To determine whether the rate of clinical progression in Huntington disease (HD) is influenced by the size of the CAG expansion.Methods: The dataset consisted of 3,402 examinations of 512 subjects seen through the Baltimore Huntington's Disease Center. Subjects were seen for a mean of 6.64 visits, with mean follow-up of 6.74 years. Subjects were administered the Quantified Neurological Examination, with its subsets the Motor Impairment and Chorea Scores, the Mini-Mental State Examination, and the HD Activities of Daily Living (ADL) Scale.Results: In an analysis based on the Random Effects Model, CAG length was significantly associated with the rate of progression of all measures except chorea and ADL. There was a significant interaction term between CAG length and disease duration for all measures except chorea. Further graphical exploration of the data supported these linear models and suggested that subjects at the low end of the expanded CAG repeat range may experience a more benign late course.Conclusions: CAG repeat length has a small effect on rate of progression that may be clinically important over time. Individuals with the shortest expansions appear to have the best prognosis. These effects of the CAG length may be relevant in the analysis of clinical trials.


Author(s):  
Elizabeth Aylward ◽  
James Mills ◽  
Dawei Liu ◽  
Peggy Nopoulos ◽  
Christopher A. Ross ◽  
...  

PLoS Currents ◽  
2011 ◽  
Vol 3 ◽  
pp. RRN1235 ◽  
Author(s):  
Elizabeth Aylward ◽  
James Mills ◽  
Dawei Liu ◽  
Peggy Nopoulos ◽  
Christopher A. Ross ◽  
...  

2019 ◽  
Author(s):  
Galen E.B. Wright ◽  
Nicholas S. Caron ◽  
Bernard Ng ◽  
Lorenzo Casal ◽  
Xiaohong Xu ◽  
...  

ABSTRACTHuntington disease (HD) is a neurodegenerative disorder that is caused by a CAG repeat expansion in the HTT gene. In an attempt to identify genomic modifiers that contribute towards the age of onset of HD, we performed a transcriptome wide association study assessing heritable differences in genetically determined expression in diverse tissues, employing genome wide data from over 4,000 patients. This identified genes that showed evidence for colocalization and replication, with downstream functional validation being performed in isogenic HD stem cells and patient brains. Enrichment analyses detected associations with various biologically-relevant gene sets and striatal coexpression modules that are mediated by CAG length. Further, cortical coexpression modules that are relevant for HD onset were also associated with cognitive decline and HD-related traits in a longitudinal cohort. In summary, the combination of population-scale gene expression information with HD patient genomic data identified novel modifier genes for the disorder.


2020 ◽  
Author(s):  
Paula Sienes Bailo ◽  
Raquel Lahoz ◽  
Juan Pelegrín Sánchez Marín ◽  
Silvia Izquierdo Álvarez

Abstract Background: Despite the progress in the knowledge of Huntington disease (HD) in recent years, the epidemiology continues uncertain, so the study of incidence becomes relevant. This is important since various factors (type of population, diagnostic criteria, disease-modifying factors, etc.) make these data highly variable. Therefore, the genetic diagnosis of these patients is important, since it unequivocally allows the detection of new cases.Methods: Descriptive retrospective study with 179 individuals. Incidence of HD was calculated from the ratio of number of symptomatic cases newly diagnosed per 100 000 inhabitants per year during the period 2007-2019 in Aragon (Spain).Results: 50 (27.9%) incident cases of HD (CAG repeat length ≥36) were identified from a total of 179 persons studied. The remaining 129/179 (73.4%) were HD negative (CAG repeat length <36). 29 (58.0%) females and 21 (42.0%) males were confirmed as HD cases. The overall incidence was 64.8 per 100 000 patient-years. 11/50 positive HD cases (22.0%) were identified by performing a predictive test, without clinical symptoms. The minimum number of CAG repeats found was 10 and the most common CAG length among HD negative individuals was 16.Conclusions: Our incidence lied within the range reported for other Caucasian populations. Implementation of new techniques has allowed to determine the exact number of CAG repeats, which is especially important in patients with triplet expansions in an HD intermediate and/or incomplete penetrance allele, both in diagnostic, predictive and prenatal tests.


2020 ◽  
Author(s):  
Paula Sienes Bailo ◽  
Raquel Lahoz ◽  
Juan Pelegrín Sánchez Marín ◽  
Silvia Izquierdo Álvarez

Abstract Background: Despite the progress in the knowledge of Huntington disease (HD) in recent years, the epidemiology continues uncertain, so the study of incidence becomes relevant. This is important since various factors (type of population, diagnostic criteria, disease-modifying factors, etc.) make these data highly variable. Therefore, the genetic diagnosis of these patients is important, since it unequivocally allows the detection of new cases.Methods: Descriptive retrospective study with 179 individuals. Incidence of HD was calculated from the ratio of number of symptomatic cases newly diagnosed per 100 000 inhabitants per year during the period 2007-2019 in Aragon (Spain). Results: 50 (27.9%) incident cases of HD (CAG repeat length ≥36) were identified from a total of 179 persons studied. The remaining 129/179 (73.4%) were HD negative (CAG repeat length <36). 29 (58.0%) females and 21 (42.0%) males were confirmed as HD cases. The overall incidence was 64.8 per 100 000 patient-years. 11/50 positive HD cases (22.0%) were identified by performing a predictive test, without clinical symptoms. The minimum number of CAG repeats found was 10 and the most common CAG length among HD negative individuals was 16.Conclusions: Our incidence lied within the range reported for other Caucasian populations. Implementation of new techniques has allowed to determine the exact number of CAG repeats, which is especially important in patients with triplet expansions in an HD intermediate and/or incomplete penetrance allele, both in diagnostic, predictive and prenatal tests.


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