scholarly journals Incidence of Huntington disease in a northeastern Spanish region: A 13-year retrospective study at tertiary care centre

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 ◽  
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 ◽  
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. Methods Descriptive retrospective study with 188 individuals. Incidence of HD was calculated from the ratio of number of symptomatic cases newly diagnosed per million 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). Male to female ratio was 1:1,4; with 29 (58.0%) females and 21 (42.0%) males confirmed HD cases. The overall incidence was 6.48 per million patient-years. 12/50 positive HD cases (24,0%) 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.


2017 ◽  
Vol 7 (1) ◽  
pp. 136-144
Author(s):  
Catherine R. Miller ◽  
Nobby C. Mambo ◽  
Jianli Dong ◽  
Gerald A. Campbell

Huntington disease (HD) is a neurodegenerative disorder with a worldwide prevalence of four to ten per 100 000. It is characterized by choreiform movements, behavioral/psychiatric disturbances, and eventual cognitive decline. Symptoms usually present between 30 and 50 years of age and the diagnosis is based on the combination of clinical symptoms, family history, and genetic testing. A variation of HD, juvenile Huntington disease (JHD), presents earlier, with more severe symptoms and with a worse prognosis. Symptoms are different in JHD, with personality changes and learning difficulties being the predominant presenting features. Seizures are common in JHD, and chorea is uncommon; movement disorders at presentation of JHD are predominantly nonchoreiform. The inheritance pattern for both HD and JHD is autosomal dominant and the disease is caused by an elongation of the CAG repeat in the huntingtin gene. There are many published case reports of Huntington disease that were confirmed at autopsy, but to our knowledge, there are no reports in the literature where the diagnosis of Huntington disease was first made at autopsy. We present a case of a 28-year-old African-American male who was in a state of neglect due to a lifetime of abuse, cognitive difficulties, and seizures, whose cause of death was pneumonia. The gross autopsy findings included bilateral caudate nucleus atrophy and lateral ventricular dilation. Microscopically, severe bilateral neuronal loss and gliosis of the caudate and putamen nuclei were seen. Genetic testing for the number of CAG repeats confirmed the diagnosis and was consistent with JHD.


2020 ◽  
Vol 6 (3) ◽  
pp. e430 ◽  
Author(s):  
Daniel O. Claassen ◽  
Jody Corey-Bloom ◽  
E. Ray Dorsey ◽  
Mary Edmondson ◽  
Sandra K. Kostyk ◽  
...  

BackgroundThe huntingtin gene (HTT) pathogenic cytosine-adenine-guanine (CAG) repeat expansion responsible for Huntington disease (HD) is phased with single nucleotide polymorphisms (SNPs), providing targets for allele-selective treatments.ObjectiveThis prospective observational study defined the frequency at which rs362307 (SNP1) or rs362331 (SNP2) was found on the same allele with pathogenic CAG expansions.MethodsAcross 7 US sites, 202 individuals with HD provided blood samples that were processed centrally to determine the number and size of CAG repeats, presence and heterozygosity of SNPs, and whether SNPs were present on the mutant HTT allele using long-read sequencing and phasing.ResultsHeterozygosity of SNP1 and/or SNP2 was identified in 146 (72%) individuals. The 2 polymorphisms were associated only with the mHTT allele in 61% (95% high density interval: 55%, 67%) of individuals.ConclusionsThese results are consistent with previous reports and demonstrate the feasibility of genotyping, phasing, and targeting of HTT SNPs for personalized treatment of HD.


2012 ◽  
Vol 15 (1) ◽  
pp. 31-36 ◽  
Author(s):  
S Madjunkova ◽  
A Eftimov ◽  
V Georgiev ◽  
D Petrovski ◽  
A Dimovski ◽  
...  

Cag Repeat Number in the Androgen Receptor Gene and Prostate CancerProstate cancer (PC) is the second leading cause of cancer deaths in men. The effects of androgens on prostatic tissue are mediated by the androgen receptor (AR) gene. The 5' end of exon 1 of the AR gene includes a polymorphic CAG triplet repeat that numbers between 10 to 36 in the normal population. The length of the CAG repeats is inversely related to the transactivation function of the AR gene. There is controversy over association between short CAG repeat numbers in the AR gene and PC. This retrospective case-control study evaluates the possible effect of short CAG repeats on the AR gene in prostate cancer risk in Macedonian males. A total of 392 male subjects, 134 PC patients, 106 patients with benign prostatic hyperplasia (BPH) and 152 males from the general Macedonian population were enrolled in this study. The CAG repeat length was determined by fluorescent polymerase chain reaction (PCR) amplification of exon1 of the AR gene followed by capillary electrophoresis (CE) on a genetic analyzer. The mean repeat length in PC patients was 21.5 ±2.65, in controls 22.28 ±2.86 (p = 0.009) and in BPH patients 22.1 ±2.52 (p = 0.038). Short CAG repeats (<19) were found in 21.64% of PC patients vs. 9.43% in BPH patients (p = 0.0154). We also found an association of low Gleason score (<7) with short CAG repeat (<19) in PC patients (p = 0.0306), and no association between the age at diagnosis of PC and BPH and CAG repeat length. These results suggest that reduced CAG repeat length may be associated with increased prostate cancer risk in Macedonian men.


2012 ◽  
Vol 2012 ◽  
pp. 1-19 ◽  
Author(s):  
Tianle Chen ◽  
Yuanjia Wang ◽  
Yanyuan Ma ◽  
Karen Marder ◽  
Douglas R. Langbehn

Huntington's disease (HD) is a progressive neurodegenerative disorder caused by an expansion of CAG repeats in the IT15 gene. The age-at-onset (AAO) of HD is inversely related to the CAG repeat length and the minimum length thought to cause HD is 36. Accurate estimation of the AAO distribution based on CAG repeat length is important for genetic counseling and the design of clinical trials. In the Cooperative Huntington's Observational Research Trial (COHORT) study, the CAG repeat length is known for the proband participants. However, whether a family member shares the huntingtin gene status (CAG expanded or not) with the proband is unknown. In this work, we use the expectation-maximization (EM) algorithm to handle the missing huntingtin gene information in first-degree family members in COHORT, assuming that a family member has the same CAG length as the proband if the family member carries a huntingtin gene mutation. We perform simulation studies to examine performance of the proposed method and apply the methods to analyze COHORT proband and family combined data. Our analyses reveal that the estimated cumulative risk of HD symptom onset obtained from the combined data is slightly lower than the risk estimated from the proband data alone.


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