Amyloidosis
Gene: APOA4
5 families with autosomal dominant medullary amyloidosis. WGS/WES identified 2 different variants in the APOA4 gene (p.D33N in 3 families and p.L66V in 2 families). The variants were absent in gnomAD, located at the structurally flexible N-terminal domain of APOA4, and segregated with disease. There were 48 genotype +ve individuals with 44/48 having an eGFR <60. All clinically affected individuals presented with a bland urinary sediment, CKD, and no clinical evidence of systemic amyloidosis. Mean age of dialysis/transplantation was 58+/-11yrs. Routine kidney biopsies limited to the kidney cortex showed tubulointerstitial fibrosis and secondary glomerulosclerosis and no amyloid deposition. Four affected individuals were shown to have isolated medullary deposition of amyloid, with mass spectrometry showing the mutated Apoa4 as the primary constituent in 3 available cases.
Plasma total ApoA4 levels were increased for patients (n=15) with ApoA4 mutations versus controls (n=49). They hypothesize that the amino acid substitutions alter the tertiary or quaternary structure of the mutated ApoA4, leading to increased plasma and primary urine concentrations and isolated medullary amyloid deposition.
Sources: LiteratureCreated: 10 Nov 2024, 10:12 p.m.
Mode of inheritance
MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Phenotypes
Autosomal dominant renal medullary amyloidosis
Publications
Phenotypes for gene: APOA4 were changed from Hereditary amyloidosis, MONDO:0018634, APOA4-related to Hereditary amyloidosis, MONDO:0018634, APOA4-related; Tubulointerstitial kidney disease, autosomal dominant 6, MIM# 621106
Gene: apoa4 has been classified as Green List (High Evidence).
Phenotypes for gene: APOA4 were changed from Autosomal dominant renal medullary amyloidosis to Hereditary amyloidosis, MONDO:0018634, APOA4-related
Gene: apoa4 has been classified as Green List (High Evidence).
gene: APOA4 was added gene: APOA4 was added to Amyloidosis. Sources: Literature Mode of inheritance for gene: APOA4 was set to MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted Publications for gene: APOA4 were set to PMID: 38096951 Phenotypes for gene: APOA4 were set to Autosomal dominant renal medullary amyloidosis Review for gene: APOA4 was set to GREEN