Laboratory for Molecular Diagnostics
Center for Nephrology and Metabolic Disorders
Moldiag Diseases Genes Support Contact

Collagen type IV, alpha 3

COL4A3 is one of two genes responsible for autosomal Alport syndrome. Depending on the type of mutation dominant or recessive inheritance is possible. The number of mutated alleles defines the severity of symptoms. Only one allele affected leads to benign hematuria, two alleles Alport syndrome.


The Alport syndrome is responsible for about 0,5-1% of patients on dialysis in Western countries. The autosomal recessive form makes only 15-20% of these.

Gene Structure

The gene COL4A3 is located on chromosome 2 (2q36-q37) in a head-to-head position with the gene COL4A4 . Both genes probably use the same promotor. The size is about 150kb. There exists 3 splice variants with 51, 49 and 48 exons.


This gene is responsible for autosomal recessive Alport syndrome. That means: in homozygous state a full blown clinical picture of Alport syndrome can be seen that is characterized by progressive nephritis, sensorineural deafness and a plethora of ocular abnormalities. In heterozygous state the clinical picture seems to be equivalent to benign familial hematuria.


The basement membranes of the body mainly consists of collagen type IV. Herein the alpha chains 3, 4 and 5 plays an special role. The highly specialized basement membranes in glomerulum, inner ear and at some ocular locations consists of these chains. Therefore, if one of these chains is disturbed symptoms in these organs are possible.

Test Strategy

This investigation is required when the diagnosis of autosomal recessive Alport syndrome has to be confirmed.


The detection of a mutation confirms autosomal recessive Alport syndrome.


Clinic Method Carrier testing
Turnaround 5 days
Specimen type genomic DNA
Clinic Method Massive parallel sequencing
Turnaround 25 days
Specimen type genomic DNA
Clinic Method Genomic sequencing of the entire coding region
Turnaround 20 days
Specimen type genomic DNA
Clinic Method Multiplex Ligation-Dependent Probe Amplification
Turnaround 20 days
Specimen type genomic DNA

Related Diseases:

Alport Syndrome
Goodpasture syndrome



Nagel M et al. (2005) Novel COL4A5, COL4A4, and COL4A3 mutations in Alport syndrome.

external link

Orphanet article

Orphanet ID 120718 external link

NCBI article

NCBI 1285 external link

OMIM.ORG article

Omim 120070 external link

Wikipedia article

Wikipedia EN (Collagen,_type_IV,_alpha_3) external link
Update: Aug. 14, 2020
Copyright © 2005-2022 by Center for Nephrology and Metabolic Disorders, Dr. Mato Nagel, MD
Albert-Schweitzer-Ring 32, D-02943 Weißwasser, Germany, Tel.: +49-3576-287922, Fax: +49-3576-287944
Sitemap | Webmail | Disclaimer | Privacy Issues | Website Credits