👤 Harto Hakonen

While physical activity (PA), sedentary time (ST), and sleep each show individual associations with learning outcomes, their combined associations remain largely unexplored. This cross-sectional study examined the association between the 24-h movement behavior composition and arithmetic and reading fluency in children and adolescents, gender differences in these associations, and theoretical 30‑minute behavior‑change scenarios. Volunteered children (N = 253, mean age: 9.5 ± 0.4 years, 53% girls) and adolescents (N = 174, mean age: 13.7 ± 0.6 years, 63% girls) participated. Children's arithmetic fluency was measured using the FUNA test battery, and reading fluency with the Sentence Reading fluency test. Adolescents' arithmetic fluency was measured with the Basic Arithmetic Test, and reading fluency with the word reading task ALLU. Light PA, moderate PA, vigorous PA, and ST were measured using hip-worn accelerometers (ActiGraph GT3X +). Students recorded their sleep time. The associations were examined using compositional data analysis. The ratios of behaviors were predictors within linear mixed models, adjusted for age, gender, special educational needs, body fat percentage, and guardians' education. The light PA relative to other behaviors was inversely associated with reading fluency (β = - 0.98, p = 0.014) among children. No other behaviors were associated with reading or arithmetic fluency in children or adolescents. Among adolescents, there was a significant interaction effect of gender and the time spent in ST on reading fluency (β = - 2,85, p = 0.037), but not on arithmetic fluency. Together, the interaction and main effects indicate that higher ST is linked to better reading fluency for both genders, with a stronger association in boys. Among adolescents, predicted 30‑minute reallocations from ST to sleep, or moderate PA, as well as from LPA to sleep, increased the difference in reading fluency between girls and boys. Lower levels of light-intense PA were linked to better children's reading fluency. The association between the 24-h activity composition and reading fluency among adolescents may differ between boys and girls. From a 24-h movement behavior perspective, supporting reading may require strategies that are tailored by age and gender. Show less

Fetal akinesia deformation sequence (FADS) and lethal multiple pterygium syndrome (LMPS) are clinically overlapping syndromes manifesting with reduced or absent fetal movement, arthrogryposis, and several anomalies during fetal life. The etiology of these syndromes is heterogeneous, and in many cases it remains unknown. In order to determine the genetic etiology of FADS in two fetuses with fetal akinesia, arthrogryposis, edema, and partial cleft palate, we utilized exome sequencing. Our investigations revealed a homozygous nonsense variant [c.1116C>A, p.(Cys372Ter)] in the SLC18A3 gene, which encodes for the vesicular acetylcholine transporter (VAChT) responsible for active transport of acetylcholine in the neuromuscular junction. This is the first description of a nonsense variant in the SLC18A3 gene, as only missense variants and whole gene deletions have been previously identified in patients. The previously detected SLC18A3 defects have been associated with congenital myasthenic syndromes, and therefore our findings extend the clinical spectrum of SLC18A3 defects to severe prenatal phenotypes. Our findings suggest that nonsense variants in SLC18A3 cause a more severe phenotype than missense variants and are in line with previous studies showing a lethal phenotype in VAChT knockout mice. Our results underline the importance of including SLC18A3 sequencing in the differential diagnostics of fetuses with arthrogryposis, FADS, or LMPS of unknown etiology. Show less