Distinct Magnetic Resonance Imaging in a Child With a TACO1 Variant.

This case report describes a unique magnetic resonance imaging result in a young boy with a TACO1 variant.

Delta progradation in Greenland driven by increasing glacial mass loss.

Climate changes are pronounced in Arctic regions and increase the vulnerability of the Arctic coastal zone. For example, increases in melting of the Greenland Ice Sheet and reductions in sea ice and permafrost distribution are likely to alter coastal morphodynamics. The deltas of Greenland are largely unaffected by human activity, but increased freshwater runoff and sediment fluxes may increase the size of the deltas, whereas increased wave activity in ice-free periods could reduce their size, with the net impact being unclear until now. Here we show that southwestern Greenland deltas were largely stable from the 1940s to 1980s, but prograded (that is, sediment deposition extended the delta into the sea) in a warming Arctic from the 1980s to 2010s. Our results are based on the areal changes of 121 deltas since the 1940s, assessed using newly discovered aerial photographs and remotely sensed imagery. We find that delta progradation was driven by high freshwater runoff from the Greenland Ice Sheet coinciding with periods of open water. Progradation was controlled by the local initial environmental conditions (that is, accumulated air temperatures above 0 °C per year, freshwater runoff and sea ice in the 1980s) rather than by local changes in these conditions from the 1980s to 2010s at each delta. This is in contrast to a dominantly eroding trend of Arctic sedimentary coasts along the coastal plains of Alaska, Siberia and western Canada, and to the spatially variable patterns of erosion and accretion along the large deltas of the main rivers in the Arctic. Our results improve the understanding of Arctic coastal evolution in a changing climate, and reveal the impacts on coastal areas of increasing ice mass loss and the associated freshwater runoff and lengthening of open-water periods.

Sea-level proxies in Holocene raised beach ridge deposits (Greenland) revealed by ground-penetrating radar.

Identification of sea-level proxies is important for reconstruction of past sea-level variation. Methods for reconstructing Holocene relative sea-level curves are crucial for quantification of the impact of Greenland ice thickness variation on global sea level and vertical land movement. Arctic beach ridges constitute important potential archives of sea-level variation. However, their surface morphology may have undergone modification since deposition due to freezing/thawing processes and erosion, and their morphology may therefore not be trustworthy for sea-level reconstruction. Therefore, geophysical imaging is used to examine the internal structures of the beach ridges and to define a sea-level proxy unaffected by surface processes. The GPR reflections from study sites in West and South Greenland show deposition of beachface deposits and upper shoreface deposits; the contact between steeply dipping beachface reflections and less-dipping shoreface reflections is used as sea-level proxy. Numerous points are identified along GPR transects facilitating reconstruction of relative sea-level variation of hitherto unprecedented resolution. Erosional events and deformation caused by freezing/thawing processes are clearly delineated. The approach constitutes a solid base for reconstruction of relative sea-level curves affected by a well-defined vertical land movement history since the studied beach ridge systems represent long time intervals and only relatively small spatial extents.

Deltas, freshwater discharge, and waves along the Young Sound, NE Greenland.

A wide range of delta morphologies occurs along the fringes of the Young Sound in Northeast Greenland due to spatial heterogeneity of delta regimes. In general, the delta regime is related to catchment and basin characteristics (geology, topography, drainage pattern, sediment availability, and bathymetry), fluvial discharges and associated sediment load, and processes by waves and currents. Main factors steering the Arctic fluvial discharges into the Young Sound are the snow and ice melt and precipitation in the catchment, and extreme events like glacier lake outburst floods (GLOFs). Waves are subordinate and only rework fringes of the delta plain forming sandy bars if the exposure and fetch are optimal. Spatial gradients and variability in driving forces (snow and precipitation) and catchment characteristics (amount of glacier coverage, sediment characteristics) as well as the strong and local influence of GLOFs in a specific catchment impede a simple upscaling of sediment fluxes from individual catchments toward a total sediment flux into the Young Sound.

Possible associations between successful aging and polymorphic markers in the Werner gene region.

Werner syndrome (WS) is an autosomal recessive segmental progeroid syndrome caused by mutations in the Werner (WRN) gene leading to the early onset of many (but not all) aspects of normal aging. To investigate whether the WRN gene affects the course of aging in non-Werner syndrome individuals, we performed association studies analyzing several single nucleotide polymorphisms (SNPs) in the WRN locus. We found certain close-set SNPs in the 5' flanking region and 5' UTR to be significantly associated with the cognitive functioning level in old age.

A polymorphic marker in the first intron of the Werner gene associates with cognitive function in aged Danish twins.

Werner's syndrome is a premature aging syndrome with many features common to normal aging. The possible association between phenotypic markers for normal aging and SNP's in the WRN gene was investigated in 426 dizygotic, Danish twins age 70-90 years. All participants were scored every second year using a number of physical and cognitive tests. In addition their self-rated health was registered as well as self reported status with regards to nine diseases. Blood was drawn from all participants and purified DNA was typed for four SNP's in the WRN gene. The four SNP's were located in intron 1, exon 6, exon 9 and exon 34. In an unpaired analysis of this material a significant association between the intron 1 SNP and cognitive function was demonstrated. Our finding, which will need corroboration in independent samples, therefore may suggest that the t-allele of the intron 1 SNP is beneficial to cognitive function. However, since the t-allele of this SNP is very rare, we did not encounter any tt-homozygous individuals for this allele.

Association of chromosome 19q13.2-3 haplotypes with basal cell carcinoma: tentative delineation of an involved region using data for single nucleotide polymorphisms in two cohorts.

We have previously used single nucleotide polymorphisms to detect an association of basal cell carcinoma (BCC) in Caucasian Americans and Danes with the genome region 19q13.2-3, which contains several genes involved in the nucleotide excision repair of DNA. In this exploratory paper we have extended the data and used them in a chromosomal scan. The results indicate the presence of a gene variation modulating the risk of developing BSS in a submegabase region including and surrounding the gene RAI. Specifically, persons that are homozygous for the haplotype RAI intron 1(A) RAI exon 6(A) appear at increased risk for BCC. In addition, we have looked for possible synergisms between all pairs of markers. We find that a marker in GLTSCR1, presumably separated from RAI by several million bases, supplements the most significant marker in RAI in separating cases from controls, which may suggest the presence of an independent, risk-modulating variation in this second gene region.