We have looked for disease-causing mutations in the PKD1 gene in 20 unrelated ADPKD probands from northern Italy, all members of families in which our previous studies had indicated linkage to PKD1. Using PCR with primer pairs located in the 3' unique region of the gene and heteroduplex DNA analysis, we have detected novel aberrant bands in five affected individuals from the same family, which were absent in 13 other unaffected family members. Cloning and automated DNA sequencing revealed a C to T transition at nucleotide position 3817 of the published cDNA sequence, which created a premature stop codon. The mutation destroyed a MspA1I restriction site, and the abnormal restriction pattern was observed on genomic DNA from all the affected family members. RT-PCR and restriction analysis performed on peripheral white blood cell mRNA showed that in the affected members, both the mutant and the normal transcript are represented. This mutation was not found in the probands of the other families studied. To our knowledge, this is the first nonsense mutation described in the PKD1 gene.

Different results have been reported for skiing and snowboarding injuries worldwide. Few studies consider the injury severity score (ISS) for the evaluation of differences among injured skiers-snowboarders. The aim of this study is to identify possible risk factors that affect the severity of skiing and snowboarding injuries in three winter seasons (2002-2005) in South Tyrol. For every injured skier or snowboarder referred to our emergency department in three consecutive seasons, the following data were collected: date of birth, gender, self-declared technical skills level, place of residence (local/non-local), as well as the date, time, and place of the accident. Type of injury and ISS were retrospectively assigned. Data concerning the snowfall in the last 24 h, average snow level, and outdoor air temperature values were obtained from four weather stations that were located inside the ski resorts. A multiple linear regression model was used to evaluate the association between ISS and potential determinants. In the analyzed seasons, 2,511 injured skiers and 843 injured snowboarders were evaluated at our emergency department. There was a significant change in the ISS value for subjects with different self-reported skills levels (P < 0.001). Men and non-local residents experienced more severe injuries than women and local residents, respectively (P < 0.013, P < 0.001). The ISS was higher for people aged over 60 (P < 0.001). Snowfalls brought about a decrease in accident severity (P = 0.009). The severity of the injuries increases with age. Prevention and information programs should be targeted to people who are at high risk of severe injury. A 24-h fresh snowfall seems to reduce the severity of injuries. Very little is known about snow conditions and winter sports injury. Further studies are needed to explore this field.

Background: Sledding is a popular traditional pastime in northern countries. However it is only rarely thought as a potentially dangerous activity even though serious injuries and deaths do occur. The purpose of this study was to calculate the incidence, the severity and the pattern of sleddingrelated injuries in our area, in order to set up possible preventive measures.

Incidence, pattern of injuries and mortality from skiing and snowboarding accidents in South Tyrol resemble those reported in other part of the world. Nevertheless, strategies for prevention are needed. The routine use of helmets should be enforced by law. Dangerous behaviors should be prosecuted. Skiers and snowboarders should be made aware that skiing beyond their technical ability can be life-threatening.

Severe traumatic injuries occur among skiers and snowboarders, and preventive measures such as the use of helmets and educational programs, are necessary.