ClinVar

Description

Variant summary: PALB2 c.172_175delTTGT (p.Gln60ArgfsX7) results in a premature termination codon, predicted to cause a truncation of the encoded protein or absence of the protein due to nonsense mediated decay, which are commonly known mechanisms for disease. The variant allele was found at a frequency of 4e-05 in 277228 control chromosomes (gnomAD). This frequency is not higher than expected for a pathogenic variant in PALB2 causing Hereditary Breast and Ovarian Cancer (4e-05 vs 0.00016), allowing no conclusion about variant significance. c.172_175delTTGT has been reported in the literature in multiple individuals affected with Hereditary Breast and Ovarian Cancer (Hellebrand 2011, Casadei 2011 ,Kraus 2016) and pancreatic cancer (Jones 2009). These data indicate that the variant is very likely to be associated with disease. In addition, a case-control study found this variant to be present at a significantly higher frequency in breast cancer patients than in unaffected controls (OR=5.02; p=0.0016) (Cybulski 2015). To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. Ten clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014 without evidence for independent evaluation. All laboratories classified the variant as pathogenic (9)/likely pathogenic(1). Based on the evidence outlined above, the variant was classified as pathogenic.