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Spinocerebellar ataxia type 3 (SCA3) is caused by unstable expanded CAG repeats (expCAGs) in ATXN3. Factors associated with intergenerational instability (delta-expCAG) and genetic anticipation in SCA3 have never been reported in Chinese mainland. Here, we demonstrated that unstable transmissions occurred more often in sons than in daughters (91% vs 72%, Fisher’s exact test, p = 0.012). The extended delta-expCAG of father-son transmissions was greater than that of mother-son transmissions (3.8 ± 2.3 repeats vs 1.6 ± 1.0 repeats, Mann-Whitney U, p = 0.001). Genetic anticipation was frequently observed between generations but not affected by the delta-expCAG.

Background Many seed plants produce winged diaspores that use wind to disperse their seeds. The morphology of these diaspores is directly related to the seed dispersal potential. The majority of winged diaspores have flat wings and only seeds; however, some angiosperms, such as Firmiana produce winged fruit with a different morphology, whose seed dispersal mechanisms are not yet fully understood. In this study, we observed the fruit development of F. simplex and determined the morphological characteristics of mature fruit and their effects on the flight performance of the fruit. Results We found that the pericarp of F. simplex dehisced early and continued to unfold and expand during fruit development until ripening, finally formed a spoon-shaped wing with multiple alternate seeds on each edge. The wing caused mature fruit to spin stably during descent to provide a low terminal velocity, which was correlated with the wing loading and the distribution of seeds on the pericarp. When the curvature distribution of the pericarp surface substantially changed, the aerodynamic characteristics of fruit during descent altered, resulting in the inability of the fruit to spin. Conclusions Our results suggest that the curved shape and alternate seed distribution are necessary for the winged diaspore of F. simplex to stabilize spinning during wind dispersal. These unique morphological characteristics are related to the early cracking of fruits during development, which may be an adaptation for the wind dispersal of seeds.

Genetic mutations in transglutaminase 6 (TGM6) are recently identified to be associated with spinocerebellar ataxia type 35 (SCA35). We report a Hispanic SCA35 patient, who was confirmed to have a heterozygous, single-nucleotide deletion in TGM6, causing a frameshift mutation with a premature stop codon. An immune-mediated ataxia previously found to be associated with autoantibody reactivity to TG6 may share a similar pathomechanism to SCA35, suggesting a converging role for TG6 in cerebellar function.