Description
The CHEK2 c.320-5T>A splice region variant has been reported in a heterozygous state in at least five individuals with various cancers (Kleibl et al. 2008; Kleibl et al. 2009; Mohelnikova-Duchonova et al. 2010; Havranek et al. 2011; Kraus et al. 2016; Mucaki et al. 2016). Of these five individuals, the variant was found in one patient with sporadic breast cancer, one with colorectal cancer, one with sporadic pancreatic cancer, one with Hodgkin lymphoma, and one with hereditary breast or ovarian cancer. The c.320-5T>A variant was absent from 1366 control chromosomes (Kleibl et al. 2008), but is reported at a frequency of 0.01402 in the Iberian population in Spain from the 1000 Genomes Project. Kraus et al. (2016) demonstrated using RT-PCR analysis that the c.320-5T>A variant resulted in an in-frame transcript lacking exons 3 and 4 that was stably expressed, however at low levels (about 20%) compared to the level of wild type transcript, suggesting a leaky splicing defect and a hypomorphic allele. Based on the evidence, the c.320-5T>A variant is classified as a variant of unknown significance but suspicious for pathogenicity for CHEK2-related cancer susceptibility. This variant was observed by ICSL as part of a predisposition screen in an ostensibly healthy population.
| # | Sample | Method | Observation |
|---|
| Origin | Affected | Number tested | Tissue | Purpose | Method | Individuals | Allele frequency | Families | Co-occurrences |
|---|
| 1 | germline | unknown | not provided | not provided | not provided | | not provided | not provided | not provided | not provided |
