How 'personal' is personal genomics?

An editorial in Science this week addresses the 'gaping hole' that still exists in genomics - that is, our lack of knowledge of the biological mechanics behind genetic disease. Greater attention must be turned to systems biology, Chakravarti states, and asks the question: if each individual is genomically unique, then is each individual's biology and disease also unique? Does this lack of understanding of individual biological response to disease causing genetic mutations indicate that personal genomics is not quite as personal as some would hope?