Risk estimates for complex disorders: comparing personal genome testing and family history.

PURPOSE: Personal genome testing allows the identification of single-nucleotide polymorphisms associated with an increased risk for common complex disorders. An area of concern in the use of personal genome testing is how risk estimates generated differ from traditional measures of risk (e.g., family history analysis). We sought to analyze the concordance of risk estimates generated by family history analysis and by personal genome testing.

METHODS: Risk categorizations for 20 complex conditions included in Navigenics personal genome testing were compared with risk categorization estimates derived from family history assessment using the kappa (κ) statistic.

RESULTS: The only conditions showing slight agreement between risk assessment methods were Alzheimer disease (κ = 0.131), breast cancer (κ = 0.154), and deep vein thrombosis (κ = 0.201) in females, and colon cancer (κ = 0.124) in males. Eighty-six individuals (11.4%) were found to have additional genetic risks not assessed by personal genome testing after family and medical history assessment, including 38 individuals with family histories suggestive of hereditary cancer syndromes.

CONCLUSION: Discordance between personal genome testing and family history risk estimates suggests that these methods may provide independent information that could be used in a complementary manner. Results also support that eliciting family history adds value to overall risk assessment for individuals undergoing personal genome testing.