Renal cell cancer (RCC) accounts for 80–90% of all cancers of the kidney.¹ Clear cell carcinoma is the most common cell type among parenchymal adenocarcinomas.^2,3 Over 2% of Swedish RCC patients have a parent with RCC, and the familial risk has been about 1.6.^4,5 RCC is a manifestation in von Hippel Lindau (VHL) syndrome, in which up to one half of the mutation carriers of the VHL gene are thought to be affected; central nervous system hemangioblastomas and ocular angiomas are other common manifestations in VHL disease.^6–9 VHL related tumours are of clear cell type, as are tumours in rare familial clusters with or without chromosome 3 translocations and other syndromes with manifested RCC, such as tuberous sclerosis, Birt-Hogg-Dube syndrome, and hereditary non-polyposis colorectal cancer (HNPCC).^2,10,11 Common to these known syndromes is an apparently dominant mode of inheritance. However, in the population-based studies on familial aggregation, some evidence has been presented that the risk for RCC among siblings could be higher than that between offspring and parents, which could indicate some contribution by a recessive mode of inheritance.^12,13 Intriguingly, to our knowledge, the Swedish data, together with recent Icelandic data, are the only population-based RCC studies where sibling risks have been assessed, and both point to higher familial risks among siblings than among parents and offspring.¹⁴

The most recent update (from the year 2002) of the Swedish Family-Cancer Database was used to examine specifically the issue of possible recessive inheritance in RCC. This database includes data from Swedish families, totalling over 10.2 million individuals, and cancers from the Swedish Cancer Registry up to the year 2000 and was created by linking registers maintained at Statistics Sweden and the Swedish Cancer Registry; it therefore …