New data suggest that single-nucleotide polymorphisms (SNPs) that reduce the expression of CTLA4 are associated with minimal change disease (MCD) in children. Ohl and colleagues report that the frequencies of two such SNPs at the CTLA4 locus are increased in 96 children with biopsy-proven MCD (aged 10.7 ± 4.5 years) compared to 455 healthy adult controls. They hypothesize that the SNPs that decrease CTLA4 expression might be independent risk factors for the development of MCD.