Defining the clinical phenotype of von Hippel-Lindau disease. Experience with a large Newfoundland family

Kapilläre Hämangiome der Netzhaut beim Von-Hippel-Lindau-Syndrom

Thermal photocoagulation of small peripheral angiomas is the treatment of choice for capillary hemangiomas in patients with von Hippel-Lindau disease. Larger peripheral angiomas are better treated with beta-ray brachytherapy resulting in improved results in terms of local tumor control and the side effects of treatment. Photodynamic treatment is an alternative option in the management of capillary hemangiomas of the retina. Further improvement of the treatment results of photodynamic therapy may be achieved by combination with intravitreal drugs. External beam radiation using either stereotactic techniques or proton radiation must be considered as experimental. The treatment of juxtapapillary angiomas is still a therapeutic dilemma. Vitreoretinal surgery should be confined to advanced stages with tractional detachment or when no other treatment option is available to salvage the eye.

Clinical and genetic epidemiology of inherited renal disease in Newfoundland

Clinical and genetic epidemiology of inherited renal disease in Newfoundland. Newfoundland's geography, settlement, and socioeconomic development have produced a population useful for the study of genetic diseases. This review examines the clinical and genetic epidemiologic studies of inherited renal diseases undertaken in this population in the past 15 years. Common founder effects and large families through each generation provided very extensive pedigrees with autosomal-dominant diseases, such as polycystic kidney disease (PKD) and von Hippel-Lindau disease. In the former disease the diagnostic utility of renal ultrasound was determined, as was the prognostic impact of genotype, the role of the renin-angiotensin system in the pre-hypertensive phase, the potential for somatic mutations of the PKD2 gene, or the combination of mutations in the PKD1 and PKD2 genes, in single cells to induce cysts, and the demonstration that human transheterozygotes of PKD1 and -2 are not embryonically lethal. The presence of multiple genetic isolates and the high coefficient of kinship have predisposed to autosomal recessive diseases such as Bardet-Biedl syndrome (BBS), autosomal-recessive PKD, primary hyperoxaluria, and dihydroxyadenine urolithiasis. We have reported the clinical manifestations and natural history of the BBS, with particular emphasis on the fact that renal abnormalities are cardinal manifestations of the disease, the presence of at least six different genotypes, the identity and function of the BBS6 gene, and the presence of three different BBS6 mutations. Because of its relatively homogenous origins and high coefficient of kinship, Newfoundland's population also may be useful for the study of complex diseases such as preeclampsia. Using unbiased ascertainment and strict diagnostic criteria, we have found a significant risk of preeclampsia and non-proteinuric gestational hypertension in sisters of probands with preeclampsia, particularly when probands are defined by severity of preeclampsia, an observation that supports a study to search for susceptibility genes. We conclude that collaborations between clinical epidemiologists and molecular geneticists, using the Newfoundland population, have provided important clinical and mechanistic insights into inherited renal diseases.