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Casadei S.,University of Washington | Heikkinen T.,University of Helsinki | Pylkas K.,University of Oulu | Roberts J.,University of Cambridge | And 43 more authors.
New England Journal of Medicine | Year: 2014

BACKGROUND: Germline loss-of-function mutations in PALB2 are known to confer a predisposition to breast cancer. However, the lifetime risk of breast cancer that is conferred by such mutations remains unknown. METHODS: We analyzed the risk of breast cancer among 362 members of 154 families who had deleterious truncating, splice, or deletion mutations in PALB2. The age-specific breast-cancer risk for mutation carriers was estimated with the use of a modified segregation-analysis approach that allowed for the effects of PALB2 genotype and residual familial aggregation. RESULTS: The risk of breast cancer for female PALB2 mutation carriers, as compared with the general population, was eight to nine times as high among those younger than 40 years of age, six to eight times as high among those 40 to 60 years of age, and five times as high among those older than 60 years of age. The estimated cumulative risk of breast cancer among female mutation carriers was 14% (95% confidence interval [CI], 9 to 20) by 50 years of age and 35% (95% CI, 26 to 46) by 70 years of age. Breast-cancer risk was also significantly influenced by birth cohort (P < 0.001) and by other familial factors (P = 0.04). The absolute breast-cancer risk for PALB2 female mutation carriers by 70 years of age ranged from 33% (95% CI, 25 to 44) for those with no family history of breast cancer to 58% (95% CI, 50 to 66) for those with two or more first-degree relatives with breast cancer at 50 years of age. CONCLUSIONS: Loss-of-function mutations in PALB2 are an important cause of hereditary breast cancer, with respect both to the frequency of cancer-predisposing mutations and to the risk associated with them. Our data suggest the breast-cancer risk for PALB2 mutation carriers may overlap with that for BRCA2 mutation carriers. Copyright © 2014 Massachusetts Medical Society.

Tomiak E.,Eastern Ontario Regional Genetics Program | Tomiak E.,University of Ottawa | Samson A.,University of Ottawa | Spector N.,University of Ottawa | And 9 more authors.
Familial Cancer | Year: 2014

The aim of this qualitative study was to examine the experience of individuals facing a choice about genetic counselling/testing in the context of newly diagnosed colorectal cancer (CRC). Nineteen individuals with newly diagnosed CRC, including 12 individuals who accepted genetic counselling ("acceptors") and 7 individuals who declined genetic counselling ("refusers"), were interviewed using a standardized questionnaire guide which focused on motivations and barriers experienced in the decision process. Data were analyzed using Karlsson's Empirical Phenomenological method of data analysis (Karlsson in Psychological qualitative research from a phenomenological perspective. Almgvist and Wiksell International, Stockholm, 1993). Three major themes were identified: facing challenges in health literacy; mapping an unknown territory; and adjusting to cancer. The study participants' testimonies provided novel insights into potential reasons for patient non-engagement in pilot studies of reflex testing for Lynch syndrome, and allowed us to formulate several recommendations for enhancing patient engagement. Our study findings suggest that patient engagement in clinical cancer genetics services, including reflex testing for Lynch syndrome, can only be achieved by addressing current health literacy issues, by deconstructing current misconceptions related to potential abuses of genetic information, by emphasizing the clinical utility of genetic assessment, and by adapting genetics practices to the specific context of cancer care. © 2013 The Author(s).

Baker M.,Mayo Clinic Jacksonville | Strongosky A.J.,Mayo Clinic Jacksonville | Sanchez-Contreras M.Y.,Mayo Clinic Jacksonville | Yang S.,Complete Genomics | And 12 more authors.
Neurogenetics | Year: 2014

Idiopathic basal ganglia calcification (IBGC) is characterized by bilateral calcification of the basal ganglia associated with a spectrum of neuropsychiatric and motor syndromes. In this study, we set out to determine the frequency of the recently identified IBGC gene SLC20A2 in 27 IBGC cases from the Mayo Clinic Florida Brain Bank using both Sanger sequencing and TaqMan copy number analysis to cover the complete spectrum of possible mutations. We identified SLC20A2 pathogenic mutations in two of the 27 cases of IBGC (7 %). Sequencing analysis identified a p.S113*nonsense mutation in SLC20A2 in one case. TaqMan copy number analysis of SLC20A2 further revealed a genomic deletion in a second case, which was part of a large previously reported Canadian IBGC family with dystonia. Subsequent whole-genome sequencing in this family revealed a 563,256-bp genomic deletion with precise breakpoints on chromosome 8 affecting multiple genes including SLC20A2 and the known dystonia-related gene THAP1. The deletion co-segregated with disease in all family members. The deletion of THAP1 in addition to SLC20A2 in the Canadian IBGC family may contribute to the severe and early onset dystonia in this family. The identification of an SLC20A2 genomic deletion in a familial form of IBGC demonstrates that reduced SLC20A2 in the absence of mutant protein is sufficient to cause neurodegeneration and that previously reported SLC20A2 mutation frequencies may be underestimated. © 2013 Springer-Verlag Berlin Heidelberg.

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