Clinical manifestations of homozygote allele carriers in Huntington disease
| Autor: | Maria A. Ramos-Arroyo, Sara Calvo, Natividad Mariscal, Frederic Sampedro Santalo, Laura Aguado, Saul-Indra Martinez-Horta, Ignacio Muñoz, Esther Cubo, Cecilia Gil-Polo, Katia Llano, Asunción Martínez Descalls, Aranzazu Gutierrez, Dolores Diaz |
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| Rok vydání: | 2018 |
| Předmět: |
Adult
Male medicine.medical_specialty Disease medicine.disease_cause Gastroenterology Severity of Illness Index 03 medical and health sciences 0302 clinical medicine Internal medicine Bayesian multivariate linear regression Severity of illness medicine Humans 030212 general & internal medicine Longitudinal Studies Allele Alleles Aged Mutation business.industry Homozygote Case-control study Heterozygote advantage Middle Aged Huntington Disease Phenotype Case-Control Studies Disease Progression Female Neurology (clinical) business Trinucleotide repeat expansion Trinucleotide Repeat Expansion 030217 neurology & neurosurgery |
| Zdroj: | NEUROLOGY r-IIB SANT PAU. Repositorio Institucional de Producción Científica del Instituto de Investigación Biomédica Sant Pau instname |
| ISSN: | 1526-632X 0028-3878 |
| Popis: | Objective Because patients homozygous for Huntington disease (HD) receive the gain-of-function mutation in a double dose, one would expect a more toxic effect in homozygotes than in heterozygotes. Our aim was to investigate the phenotypic differences between homozygotes with both alleles >= 36 CAG repeats and heterozygotes with 1 allele >= 36 CAG repeats. Methods This was an international, longitudinal, case-control study (European Huntington's Disease Network Registry database). Baseline and longitudinal total functional capacity, motor, cognitive, and behavioral scores of the Unified Huntington's Disease Rating Scale (UHDRS) were compared between homozygotes and heterozygotes. Four-year follow-up data were analyzed using longitudinal mixed-effects models. To estimate the association of age at onset with the length of the shorter and larger allele in homozygotes and heterozygotes, regression analysis was applied. Results Of 10,921 participants with HD (5,777 female [52.9%] and 5,138 male [47.0%]) with a mean age of 55.1 +/- 14.1 years, 28 homozygotes (0.3%) and 10,893 (99.7%) heterozygotes were identified. After correcting for multiple comparisons, homozygotes and heterozygotes had similar age at onset and UHDRS scores and disease progression. In the multivariate linear regression analysis, the longer allele was the most contributing factor to decreased age at HD onset in the homozygotes (p < 0.0001) and heterozygotes (p < 0.0001). Conclusions CAG repeat expansion on both alleles of the HTT gene is infrequent. Age at onset, HD phenotype, and disease progression do not significantly differ between homozygotes and heterozygotes, indicating similar effect on the mutant protein. Classification of evidence This study provides Class II evidence that age at onset, the motor phenotype and rate of motor decline, and symptoms and signs progression is similar in homozygotes compared to heterozygotes. |
| Databáze: | OpenAIRE |
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