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COL4A4

Synonyms
ATS2, BFH, CA44
External resources
Summary
This gene encodes one of the six subunits of type IV collagen, the major structural component of basement membranes. This particular collagen IV subunit, however, is only found in a subset of basement membranes. Like the other members of the type IV collagen gene family, this gene is organized in a head-to-head conformation with another type IV collagen gene so that each gene pair shares a common promoter. Mutations in this gene are associated with type II autosomal recessive Alport syndrome (hereditary glomerulonephropathy) and with familial benign hematuria (thin basement membrane disease). Two transcripts, differing only in their transcription start sites, have been identified for this gene and, as is common for collagen genes, multiple polyadenylation sites are found in the 3' UTR.

Variant counts

The variants found in rare patients tested by 3billion are classified and counted according to ACMG guidelines. The variants with over 5% variant frequency in population genome databases ( gnomAD, dbSNP, etc) are excluded.

Pathogenic
46
Likely pathogenic
11
VUS
18,622
Likely benign
3,151
Benign
3,483

Patient phenotypes

Proportions of phenotypes among 51 patients carrying pathogenic or likely pathogenic variants on COL4A4 gene are displayed below.

Phenotype class
Patients in 3billion (%)
Abnormality of the genitourinary system
41.2%
Abnormality of the nervous system
19.6%
Abnormality of the ear
13.7%
Abnormality of the eye
13.7%
Abnormality of the musculoskeletal system
13.7%
Abnormality of the cardiovascular system
9.8%
Abnormality of head or neck
3.9%
Abnormality of limbs
3.9%
Abnormality of the digestive system
3.9%
Growth abnormality
3.9%
Abnormality of blood and blood-forming tissues
2%
Abnormality of prenatal development or birth
2%
Abnormality of the integument
2%
Constitutional symptom
2%
Abnormal cellular phenotype
0%
Abnormality of metabolism homeostasis
0%
Abnormality of the breast
0%
Abnormality of the endocrine system
0%
Abnormality of the immune system
0%
Abnormality of the respiratory system
0%
Abnormality of the thoracic cavity
0%
Abnormality of the voice
0%
Neoplasm
0%

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