| Objective Hemolytic uremic syndrome (HUS) is characterized by the triad of thrombocytopenia, microangiopathic hemolytic anemia and acute renal failure. HUS is classified as either diarrhoeal-associated (D+HUS) or non-diarrhoeal/atypical HUS (aHUS). D+HUS is the most common form. Its clinical outcome is favorable, with recovery rates of up to 75%. The aHUS is rare, accounting for 5%-10% of the cases with HUS, and has a poor prognosis, with death rates of up to 25% of the patients with aHUS in the acute phase and 50% of the cases with aHUS progressing to end-stage renal disease. Recent studies have demonstrated that mutations in CFI, mapped to 4q25 and encoding complement factor I (CFI), are responsible for autosomal recessive aHUS. The CFI gene consists of 13 exons. CFI is a major regulatory protein of the complement system and downregulates the alternative and classical complement pathways. Different groups from European and American countries have screened mutations in CFI in patients with aHUS, documenting a mutation detection rate of 2.6-15.2% in the patients with aHUS. However, whether or not CFI is the causative gene in aHUS in Chinese children has not been established. This study is to examine mutations in the CFI gene in 9 children with aHUS in Chinese Han ethnic group. Methods Peripheral blood samples were collected for genetic analysis from 9 children with aHUS and 50 adults with normal urinalysis. Genomic DNA was isolated from peripheral blood leucocytes. Thirteen exons of CFI were amplified by polymerase chain reaction. Mutational analysis was performed by DNA sequencing. Results No causative mutation in the CFI gene was found in the 9 patients. However, 6 variants of the CFI gene, IVS5+61G>A,804G>A,IVS7+99delT,IVS8-49C>G,IVS11+33A>G and *112C>T were identified in some patients and controls, all of which are already reported CFI polymorphisms. Conclusion Mutations in the CFI gene are not major causes of the 9 children with aHUS in Chinese Han ethnic group in the study. |
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