ClinVar Genomic variation as it relates to human health

This sequence change replaces phenylalanine, which is neutral and non-polar, with cysteine, which is neutral and slightly polar, at codon 627 of the ATM protein (p.Phe627Cys). This variant is present in population databases (rs546087885, gnomAD 0.003%). This missense change has been observed in individual(s) with breast cancer (PMID: 11996792, 12935922, 19781682). ClinVar contains an entry for this variant (Variation ID: 232928). 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: "Benign"; Align-GVGD: "Class C15"). In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance.

Not observed at a significant frequency in large population cohorts (Lek 2016); In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; This variant is associated with the following publications: (PMID: 11996792, 19781682, 12935922, 28779002)

The p.F627C variant (also known as c.1880T>G), located in coding exon 11 of the ATM gene, results from a T to G substitution at nucleotide position 1880. The phenylalanine at codon 627 is replaced by cysteine, an amino acid with highly dissimilar properties. This alteration has been detected in 1/4112 breast cancer patients and 0/2399 healthy control individuals across numerous studies (Tavtigian S et al. Am J Hum Genet. 2009 Oct;85(4):427-46). This alteration has been reported in the germline of 2 of 8920 ethnically matched normal population control subjects but was not seen in 516 samples from a study of chronic lymphocytic leukemia patients of European descent (Tiao G et al. Leukemia, 2017 10;31:2244-2247). This variant was also identified in a patient with breast cancer (Bernstein JL et al. J Natl Cancer Inst, 2010 Apr;102:475-83). This amino acid position is well conserved in available vertebrate species. In addition, the in silico prediction for this alteration is inconclusive. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear.

Variant summary: ATM c.1880T>G (p.Phe627Cys) results in a non-conservative amino acid change in the encoded protein sequence. Three of five in-silico tools predict a damaging effect of the variant on protein function. The variant allele was found at a frequency of 1.2e-05 in 250808 control chromosomes (gnomAD). The available data on variant occurrences in the general population are insufficient to allow any conclusion about variant significance. c.1880T>G has been reported in the literature in individuals affected with Breast Cancer (Bernstein_2010, Sommer_2003, Tavtigian_2009). These reports do not provide unequivocal conclusions about association of the variant with Breast Cancer. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. Six ClinVar submissions (evaluation after 2014) cite the variant as uncertain significance. Based on the evidence outlined above, the variant was classified as uncertain significance.

This missense variant replaces phenylalanine with cysteine at codon 627 of the ATM protein. Computational prediction suggests that this variant may not impact protein structure and function (internally defined REVEL score threshold <= 0.5, PMID: 27666373). To our knowledge, functional studies have not been reported for this variant. This variant has been reported in individuals affected with breast cancer (PMID: 11996792, 12935922, 19781682). In a large international case-control study, this variant was reported in 7/60466 breast cancer cases and 1/53461 controls (OR=6.19, 95%CI 0.761 to 50.312, p-value=0.074; PMID: 33471991). This variant has been identified in 4/282200 chromosomes in the general population by the Genome Aggregation Database (gnomAD). The available evidence is insufficient to determine the role of this variant in disease conclusively. Therefore, this variant is classified as a Variant of Uncertain Significance.

Variant interpretted as Uncertain significance and reported on 12-16-2019 by Lab or GTR ID Credit Valley Hospital Department of Laboratory Medicine. GenomeConnect assertions are reported exactly as they appear on the patient-provided report from the testing laboratory. GenomeConnect staff make no attempt to reinterpret the clinical significance of the variant.