No abstract

Between 1960 and 2003, 13 Chinese expeditions successfully reached the summit of Chomolungma (Mt Everest or Sagarmatha). Forty-five of the 80 summiteers were Tibetan highlanders. During these and other high-altitude expeditions in Tibet, a series of medical and physiological investigations were carried out on the Tibetan mountaineers. The results suggest that these individuals are better adapted to high altitude and that, at altitude, they have a greater physical capacity than Han (ethnic Chinese) lowland newcomers. They have higher maximal oxygen uptake, greater ventilation, more brisk hypoxic ventilatory responses, larger lung volumes, greater diffusing capacities, and a better quality of sleep. Tibetans also have a lower incidence of acute mountain sickness and less body weight loss. These differences appear to represent genetic adaptations and are obviously significant for humans at extreme altitude. This paper reviews what is known about the physiologic responses of Tibetans at extreme altitudes.

Alternating hemiplegia of childhood (AHC) is a rare and severe neurodevelopmental disorder characterized by recurrent hemiplegic episodes. Most AHC cases are sporadic and caused by de novo ATP1A3 pathogenic variants. In this study, the aim was to identify the origin of ATP1A3 pathogenic variants in a Chinese cohort. In 105 probands including 101 sporadic and 4 familial cases, 98 patients with ATP1A3 pathogenic variants were identified, and 96.8% were confirmed as de novo. Micro‐droplet digital polymerase chain reaction was applied for detecting ATP1A3 mosaicism in 80 available families. In blood samples, four asymptomatic parents, including two paternal and two maternal, and one proband with a milder phenotype were identified as mosaicism. Six (7.5%) parental mosaicisms were identified in multiple tissues, including four previously identified in blood and two additional cases identified from paternal sperms. Mosaicism was identified in multiple tissues with varied mutant allele fractions (MAFs, 0.03%‐33.03%). The results suggested that MAF of mosaicism may be related to phenotype severity. This is the first systematic report of ATP1A3 mosaicism in AHC and showed mosaicism as an unrecognized source of previously considered “de novo” AHC. Identifying ATP1A3 mosaicism provides more evidence for estimating recurrence risk and has implications in genetic counseling of AHC.

The rise of modern socio‐digital technologies has fundamentally changed the everyday environments in which young people communicate with each other and cultivate interests. To gain a more sophisticated understanding of this phenomenon, this study provides in‐depth, qualitative insights into adolescents' experiences of their socio‐digital developmental ecologies. The 15 interview participants were recruited based on a previously conducted questionnaire. The semi‐structured theme interview addressed the socio‐digital aspects of the participants' interest‐driven behaviours and related networks with the aid of participant‐generated egocentric maps. The data not only qualitatively enrich the picture on adolescents' friendship‐ and interest‐driven socio‐digital participation but also provide new perspectives on the phenomena through the added network‐layer of analysis. The youth seem to vary in their motivational profiles related to their participation and the potential relevant psychological background factors for this variation are considered. Educational implications of these results are discussed when it comes to effective student engagement and connected learning.