ObjectiveThe huntingtin gene is critical for the formation and differentiation of the CNS, which raises questions about the neurodevelopmental effect of CAG expansion mutations within this gene (mHTT) that cause Huntington disease (HD). We sought to test the hypothesis that child and adolescent carriers of mHTT exhibit different brain growth compared to peers without the mutation by conducting structural MRI in youth who are at risk for HD. We also explored whether the length of CAG expansion affects brain development.MethodsChildren and adolescents (age 6–18) with a parent or grandparent diagnosed with HD underwent MRI and blinded genetic testing to confirm the presence or absence of mHTT. Seventy-five individuals were gene-expanded (GE) and 97 individuals were gene-nonexpanded (GNE). The GE group was estimated to be on average 35 years from clinical onset. Following an accelerated longitudinal design, age-related changes in brain regions were estimated.ResultsAge-related striatal volume changes differed significantly between the GE and GNE groups, with initial hypertrophy and more rapid volume decline in GE. This pattern was exaggerated with CAG expansion length for CAG > 50. A similar age-dependent group difference was observed for the globus pallidus, but not in other major regions.ConclusionOur results suggest that pathogenesis of HD begins with abnormal brain development. An understanding of potential neurodevelopmental features associated with mHTT may be needed for optimized implementation of preventative gene silencing therapies, such that normal aspects of neurodevelopment are preserved as neurodegeneration is forestalled.

ObjectiveTo assess brain morphometry in a sample of patients with juvenile-onset Huntington disease (JOHD) and several mouse models of Huntington disease (HD) that likely represent the human JOHD phenotype.MethodsDespite sharing the mutation in the Huntingtin gene, adult-onset HD characteristically presents as a hyperkinetic motor disorder, while JOHD typically presents as a hypokinetic motor disease. The University of Iowa Kids-JHD program enrolls individuals 5 to 25 years of age who have already received the clinical diagnosis. A total of 19 children with juvenile HD (JHD) (mean CAG = 72) were studied. Patients with JHD were compared to healthy controls (n = 234) using a cross-sectional study design. Volumetric data from structural MRI was compared between groups. In addition, we used the same procedure to evaluate brain morphology of R6/2, zQ175, HdhQ250 HD mice models.ResultsParticipants with JHD had substantially reduced intracranial volumes. After controlling for the small intracranial volume size, the volumes of subcortical regions (caudate, putamen, globus pallidus, and thalamus) and of cortical white matter were significantly decreased in patients with JHD. However, the cerebellum was proportionately enlarged in the JHD sample. The cerebral cortex was largely unaffected. Likewise, HD mice had a lower volume of striatum and a higher volume of cerebellum, mirroring the human MRI results.ConclusionsThe primary pathology of JOHD extends beyond changes in the striatal volume. Brain morphology in both mice and human patients with JHD shows proportional cerebellar enlargement. This pattern of brain changes may explain the unique picture of hypokinetic motor symptoms in JHD, which is not seen in the hyperkinetic chorea-like phenotype of adult-onset HD.

Стаття колективу провідних вчених педіатрів та організаторів педіатричної охорони здоров’я України присвячена вивченню основних тенденцій у стані здоров’я дитячого населення країни за останні 22 роки. Аналіз захворюваності та поширеності хвороб серед дитячого населення України, рівнів малюкової смертності протягом останніх двох десятиліть свідчить про те, що вони залишаються значно вищими від середньоєвропейських показників на тлі прогресивного зменшення чисельності дитячої популяції на 3,16 млн осіб. Поширеність дитячих хвороб в Україні за останні 22 роки зросла на 41 %, захворюваність на дитячі хвороби — на 36 %. Розглянуті шляхи вирішення низки нових соціальних та медико-екологічних проблем, що негативно впливають на здоров’я дітей.

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