Total submissions: 2
| Submitter | RCV | SCV | Clinical significance | Condition | Last evaluated | Review status | Method | Comment |
|---|---|---|---|---|---|---|---|---|
| Labcorp Genetics |
RCV001070841 | SCV001236115 | likely pathogenic | Ehlers-Danlos syndrome, type 4 | 2020-02-15 | criteria provided, single submitter | clinical testing | In summary, the currently available evidence indicates that the variant is pathogenic, but additional data are needed to prove that conclusively. Therefore, this variant has been classified as Likely Pathogenic. Glycine residues within the Gly-Xaa-Yaa repeats of the triple helix domain are required for the structure and stability of fibrillar collagens (PMID: 7695699, 8218237, 19344236). In COL3A1, variants that affect these glycine residues are significantly enriched in individuals with disease (PMID: 24922459, 25758994) compared to the general population (ExAC). Algorithms developed to predict the effect of missense changes on protein structure and function are either unavailable or do not agree on the potential impact of this missense change (SIFT: "Deleterious"; PolyPhen-2: "Not Available"; Align-GVGD: "Class C0"). This variant has not been reported in the literature in individuals with COL3A1-related conditions. This variant is not present in population databases (ExAC no frequency). This sequence change replaces glycine with aspartic acid at codon 432 of the COL3A1 protein (p.Gly432Asp). The glycine residue is highly conserved and there is a moderate physicochemical difference between glycine and aspartic acid. |
| Ambry Genetics | RCV002379628 | SCV002692869 | likely pathogenic | Familial thoracic aortic aneurysm and aortic dissection | 2018-03-12 | criteria provided, single submitter | clinical testing | The p.G432D variant (also known as c.1295G>A), located in coding exon 19 of the COL3A1 gene, results from a G to A substitution at nucleotide position 1295. The glycine at codon 432 is replaced by aspartic acid, an amino acid with similar properties. The majority (approximately two-thirds) of COL3A1 mutations identified to date have involved the substitution of another amino acid for glycine within the triple-helical domain (Pepin MG et al. Genet Med. 2014;16(12):881-8; Frank M et al. Eur J Hum Genet. 2015;23(12):1657-64). Internal structural analysis has demonstrated that this alteration disrupts the characteristic G-X-Y motif in the COL3A1 protein and inserts a bulky side chain into a sterically-constrained region (Bella J et al. Science. 1994;266:75-81; Hohenester E et al. Proc. Natl. Acad. Sci. U.S.A. 2008;105:18273-7; Ambry internal data). This amino acid position is highly conserved in available vertebrate species. In addition, this alteration is predicted to be deleterious by in silico analysis. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. |