The colonization of the human gut microbiome begins at birth, and over time, these microbial communities become increasingly complex. Most of what we currently know about the human microbiome, especially in early stages of development, was described using culture-independent sequencing methods that allow us to identify the taxonomic composition of microbial communities using genomic techniques, such as amplicon or shotgun metagenomic sequencing. Each method has distinct tradeoffs, but there has not been a direct comparison of the utility of these methods in stool samples from very young children, which have different features than those of adults. We compared the effects of profiling the human infant gut microbiome with 16S rRNA amplicon vs. shotgun metagenomic sequencing techniques in 338 fecal samples; younger than 15, 15–30, and older than 30 months of age. We demonstrate that observed changes in alpha-diversity and beta-diversity with age occur to similar extents using both profiling methods. We also show that 16S rRNA profiling identified a larger number of genera and we find several genera that are missed or underrepresented by each profiling method. We present the link between alpha diversity and shotgun metagenomic sequencing depth for children of different ages. These findings provide a guide for selecting an appropriate method and sequencing depth for the three studied age groups.

ObjectiveTo determine whether regional grey and white matter differences characterize the brain of patients with visual snow syndrome, a newly defined neurologic condition, we used a voxel-based morphometry approach.MethodsIn order to investigate directly whole brain morphology, we performed a magnetic resonance imaging study on patients (n = 24) with visual snow syndrome and on age- and gender matched (n = 24) healthy volunteers. Voxel-based morphometry was used to determine volumetric differences in visual snow subjects. We further analysed cerebellar anatomy directly using the high-resolution spatially unbiased atlas template of the cerebellum.ResultsCompared to healthy controls, patients with visual snow syndrome had increased grey matter volume in the left primary and secondary visual cortices, the left visual motion area V5 and the left cerebellar crus I/lobule VI area. These anatomical alterations could not be explained by clinical features of the condition.ConclusionWe conclude that patients with visual snow syndrome have subtle, yet significant neuroanatomical differences in key visual and lateral cerebellar areas, which may in part explain the pathophysiologic basis of the disorder.