1 Klinisk Immunologisk Afdeling. Blodbanken og Vævstypelaboratoriet, Diagnostisk Center, Rigshospitalet, The Capital Region of Denmark2 Northern Molecular Genetics Service, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, United Kingdom.3 unknown4 Department of Paediatrics and Adolescent Medicine, Juliane Marie Centre, Rigshospitalet, The Capital Region of Denmark
We report a male infant who presented at 8 months of age with atypical hemolytic uremic syndrome (aHUS) responsive to plasma therapy. Investigation showed him to have complement factor H (CFH) deficiency associated with a homozygous CFH mutation (c.2880delT [p.Phe960fs]). Mutation screening of the child's parents revealed that the father was heterozygous for this change but that it was not present in his mother. Chromosome 1 uniparental isodisomy of paternal origin was confirmed by genotyping chromosome 1 SNPs. CD46 SNP genotyping was undertaken in this individual and another patient with CFH deficiency associated with chromosome 1 uniparental isodisomy. This showed a homozygous aHUS risk haplotype (CD46GGAAC) in the patient with aHUS and a homozygous glomerulonephritis risk haplotype (CD46AAGGT) in the patient with endocapillary glomerulonephritis. We also showed that FHL-1 (factor H-like protein 1) was present in the patient with aHUS and absent in the patient with glomerulonephritis. This study emphasizes that modifiers such as CD46 and FHL-1 may determine the kidney phenotype of patients who present with homozygous CFH deficiency.
American Journal of Kidney Diseases : the Official Journal of the National Kidney Foundation, 2013, Vol 62, Issue 5, p. 978-83