If a mum or dad of the proband is thought to have the pathogenic variant recognized during the proband, the danger to your sibs of inheriting the pathogenic variant is 50%. As a consequence of decreased penetrance, sibs who inherit the pathogenic variant might or might not develop aHUS (see https://ahuhire54297.blogunok.com/32247536/examine-this-report-on-air-handling-units-ahus