Autosomal dominant Alport syndrome: molecular analysis of the COL4A4 gene and clinical outcome

Nephrol Dial Transplant. 2009 May;24(5):1464-71. doi: 10.1093/ndt/gfn681. Epub 2009 Jan 7.


Background: Alport syndrome is a clinically and genetically heterogeneous nephropathy characterized by glomerular basement membrane lesions often associated with hearing loss and ocular anomalies. While the X-linked and the autosomal recessive forms are well known, the autosomal dominant form is not well acknowledged.

Methods: We have clinically investigated 38 patients with a diagnosis of autosomal dominant Alport syndrome belonging to eight different families. The analysis of the COL4A4 gene was performed by denaturing high performance liquid chromatography and automated DNA sequencing.

Results: In our cohort of patients, only 24.3% (9/37) reached end-stage renal disease, at the mean age of 51.2 years. Four patients had hearing loss (13.3%) and none ocular changes. Molecular analysis revealed eight novel private COL4A4 gene mutations: three frameshift, three missense and two splice-site mutations.

Conclusions: These data indicate autosomal dominant Alport syndrome as a disease with a low risk of ocular and hearing anomalies but with a significant risk to develop renal failure although at an older age than the X-linked form. We were unable to demonstrate a genotype-phenotype correlation. Altogether, these data make difficult the differential diagnosis with the benign familial haematuria due to heterozygous mutations of COL4A4 and COL4A3, especially in young patients, and with the X-linked form of Alport syndrome in families where only females are affected. A correct diagnosis and prognosis is based on a comprehensive clinical investigation in as many family members as possible associated with a broadly formal genetic analysis of the pedigree.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Collagen Type IV / genetics*
  • Diagnosis, Differential
  • Female
  • Frameshift Mutation / genetics
  • Hematuria / diagnosis
  • Hematuria / genetics
  • Heterozygote
  • Humans
  • Male
  • Middle Aged
  • Mutation / genetics*
  • Mutation, Missense / genetics
  • Nephritis, Hereditary / diagnosis*
  • Nephritis, Hereditary / genetics*
  • Pedigree
  • Polymorphism, Genetic / genetics
  • Prognosis


  • COL4A4 protein, human
  • Collagen Type IV