Atypical haemolytic uraemic syndrome

Gene: CD46

Green List (high evidence)

BIALLELIC CASES:
PMID: 40983966 Hu et al., 2025
Case of a 27-year-old Chinese male diagnosed with atypical Hemolytic Uremic Syndrome (aHUS) at the age of 8, who has experienced seven relapses over a span of 19 years. He was homozygous for a mutation in CD46: c.1127+2T>A (WES). CD46 mRNA and protein expression in the patient's peripheral blood were significantly reduced. Other modifier mutations may affect penetrance here.

PMID: 33238263 Bamhraz et al., 2020
Saudi Arabian aHUS cohort.
Patient 1 homozygous for CD46: c.736T>A (p.Phe246Ile) variant, as well as het for CFI c.540A>G (p.Glu180Glu) - both labelled VUS. Disease onset at 10yrs, complete recovery after eculizumab treatment.
Patient 5 - homozygous for CD46: c.769 C>A (p.Cys 256*) - LP, as well as heterozygous for CFI c.803 C>T (p.Ser268Leu) variant (LB). Disease onset at 2.5yrs, developed into ESRD and required a post-kidney transplant.
Patient 7 - homozygous for CD46: c.350-351dup AC (p.Glu11ThfsX17) - LP. Disease onset at 21 months. Patient responded to plasma therapy leading to full recovery.

PMID: 29644059 Khandelwal et al., 2018
Cohort of Indian children with aHUS.
Sibling pairs 2–3 and 7–8 with familial disease showed a homozygous c.286 + 2T > G splice-site mutation; in both families, the parents were consanguineous. Patient 9 had a homozygous c.104G > A, p.Cys35Tyr; his affected sibling had died before genetic evaluation. 3 unrelated families total.

PMID: 14566051 Richards et al., 2003
Family 3 - recessive aHUS, CD46 c.822T>C, p.Ser206Pro. Same mutation caused aHUS in Family 2 in a heterozygous state. Demonstrated that het patients had protein expression reduced by 50%, and it was absent in homozygotes.

MONOALLELIC:
PMID: 38317858 Al Riyami et al., 2023
Patient 5 - Omani ancestry - diagnosed with aHUS, heterozygous for CD46 c.175C>T, p.Arg59* (classified Pathogenic / suscept allele) and also het for CFH c.965-6T>C (VUS).

PMID: 34169201 Ardissino et al., 2021
Study highlights low penetrance: 2/32 carriers of CD46 mutations (from 16 different families) actually developed aHUS. Two affected carriers harboured CD46 c.98-1G>C and c.286+2T>G splice variants, both classified as LP - second variant also found in 4 healthy family members. Of all 186 individuals with a complement gene abnormality, only 28 developed aHUS - not CD46 specific.

PMID: 33224962 Piras et al., 2020
Studied 485 aHUS patients and found CD46 rare variants (RVs) in about 10%. The c.286+2T>G was the most prevalent (13/485) and was associated with <30% penetrance.
Reported a large pedigree including a proband het for CD46 c.286+2T>G with severe aHUS and developed end-stage renal failure. The father and paternal uncle with the same variant in homozygosity and six het relatives are unaffected. Flow cytometry showed about 50% reduction of CD46 expression on blood mononuclear cells from the het proband and over 90% reduction in cells from the proband's unaffected homozygous father and aunt - highlights complexity of aHUS, and that CD46 deficiency may not be enough to induce aHUS.

CD46 is associated with AD,AR {Hemolytic uremic syndrome, atypical, susceptibility to, 2}, OMIM:612922 (OMIM accessed 24th Jun 2026). The association between CD46 and semi-dominant atypical hemolytic-uremic syndrome is also classified as Definitive in ClinGen (Complement-Mediated Kidney Diseases GCEP, June 2024).

Created: 22 Jun 2026, 3:45 p.m. | Last Modified: 24 Jun 2026, 10:17 a.m.

Panel Version: 3.9

Mode of inheritance
BOTH monoallelic and biallelic, autosomal or pseudoautosomal

Phenotypes
{Hemolytic uremic syndrome, atypical, susceptibility to, 2}, OMIM:612922

Publications

• 14566051
• 29644059
• 33238263
• 33224962
• 34169201
• 38317858
• 40983966

I don't know

This gene was part of an initial gene list collated by Valerie Wilson, The National Renal Complement Therapeutics Centre, February 2019 on behalf of Yorkshire and North East GLH for the GMS Renal Specialist Test Group; Gene Symbol submitted: CD46; Suggested initial gene rating: none provided;

Created: 12 Feb 2019, 12:40 p.m.

Green List (high evidence)

Mode of inheritance
MONOALLELIC, autosomal or pseudoautosomal, imprinted status unknown

Variants in this GENE are reported as part of current diagnostic practice

Green List (high evidence)

Mode of inheritance
MONOALLELIC, autosomal or pseudoautosomal, imprinted status unknown

Comment when marking as ready: Associated with phenotype in OMIM, not in G2P. At least 6 variants

Created: 15 Aug 2016, 10:11 a.m.

Comment on mode of inheritance: Three variants reported as monoallelic. Two as compound momoallelic and c.218C>T, p.Arg25* as mono and biallelic, thought to be founder variant with variable penetrance in Sardinia

Created: 15 Aug 2016, 10:11 a.m.