High prevalence of CFHR deletions in Indian women with pregnancy-associated hemolytic uremic syndrome

Aim: Pregnancy-associated hemolytic uremic syndrome (P-aHUS) is an important cause of peripartum acute kidney injury. Studies from Europe have described mutations in complement regulator genes, and data in Indian patients is scarce. Hence this study used multiplex ligation-dependent probe amplification (MLPA) to identify variants in complement genes in P-aHUS patients.

Methods: We present 17 patients of P-aHUS who were investigated for complement protein levels and genetic analysis with MLPA for complement genes. Plasma exchange therapy was offered to all patients presenting in acute phase.

Results: Mean age 26.74 (3.36) years with 15/17 delivered by caesarean section. Eleven patients received early (within 7 days) plasma exchange, three were dialysis-dependent at 3 months and seven were dialysis-free. Only one of the three patients receiving late (after 7 days) plasma exchange was dialysis-free. MLPA showed that 11 patients had heterozygous deletions of exons 3, 5, 6 of CFHR1 and upstream region of exons 1, 2, 3, 6 and intron 4 of CFHR3 gene while four patients had homozygous deletions at the same loci. Two patients had no MLPA-detectable variations.

Conclusion: This study reports a high proportion of deletions of exons of CFHR1 & CFHR3 genes in Indian P-aHUS patients detectable by MLPA by copy number variations. This needs confirmation in large multicentre studies. Plasma exchange can be an effective therapy in the non-availability of Eculizumab.