CFHR1 and atypical hemolytic-uremic syndrome: On one chromosome, a large deletion encompassing the entire CFHR1 and CFHR3 has been identified, and on the other chromosome, a large deletion encompassing the entire CFHR1 has been identified: One copy of CFHR3 is present, and both copies of CFHR1 are deleted. These findings were confirmed by MLPA. Therefore, the increased genetic susceptibility to atypical hemolytic uremic syndrome is confirmed.