title: Is collapsing C1q nephropathy another MYH9-associated kidney disease? A case report.
abstract: C1q nephropathy is a rare kidney disease that can present with nephrotic syndrome and typically has the histologic phenotype of either minimal change disease or focal segmental glomerulosclerosis (FSGS). Disagreement exists about whether it is a distinct immune complex-mediated glomerulopathy or it resides in the spectrum of FSGS-minimal change disease. Two African American patients with C1q nephropathy histologically presenting as the collapsing variant of FSGS (collapsing C1q nephropathy) and rapid loss of kidney function were genotyped for polymorphisms in the non-muscle myosin heavy chain 9 gene (MYH9). Both cases were homozygous for the MYH9 E1 risk haplotype, the variant strongly associated with idiopathic FSGS, collapsing FSGS in human immunodeficiency virus-associated nephropathy, and focal global glomerulosclerosis (historically attributed to hypertensive nephrosclerosis). Collapsing C1q nephropathy with rapid progression to end-stage renal disease appears to reside in the MYH9-associated disease spectrum.
authors.affiliation: Department of Internal Medicine-Nephrology, Wake Forest University School of Medicine, Winston-Salem, NC, USA.
authors.forename: Amber M
authors.initials: AM
authors.lastname: Reeves-Daniel
authors.forename: Samy S
authors.initials: SS
authors.lastname: Iskandar
authors.forename: Donald W
authors.initials: DW
authors.lastname: Bowden
authors.forename: Meredith A
authors.initials: MA
authors.lastname: Bostrom
authors.forename: Pamela J
authors.initials: PJ
authors.lastname: Hicks
authors.forename: Mary E
authors.initials: ME
authors.lastname: Comeau
authors.forename: Carl D
authors.initials: CD
authors.lastname: Langefeld
authors.forename: Barry I
authors.initials: BI
authors.lastname: Freedman
mesh_terms: D000328:Adult; D001741:Black or African American / Q000235:genetics; D015922:Complement C1q / Q000378:metabolism*; D018450:Disease Progression; D005260:Female; D020022:Genetic Predisposition to Disease; D005923:Glomerulosclerosis, Focal Segmental / Q000235:genetics* / Q000473:pathology; D006239:Haplotypes; D006801:Humans; D007676:Kidney Failure, Chronic / Q000235:genetics; D007678:Kidney Glomerulus / Q000473:pathology; D007684:Kidney Tubules / Q000473:pathology; D008297:Male; D020409:Molecular Motor Proteins / Q000235:genetics*; D018995:Myosin Heavy Chains / Q000235:genetics*; D009404:Nephrotic Syndrome / Q000235:genetics; D020641:Polymorphism, Single Nucleotide
chemical_list: C103814:MYH9 protein, human; D020409:Molecular Motor Proteins; D015922:Complement C1q; D018995:Myosin Heavy Chains