The New York Times has an article, Disease Cause Is Pinpointed With Genome, which is a good overview of the status of whole genome sequencing for disease research.
Besides identifying disease genes, one team, in Seattle, was able to make the first direct estimate of the number of mutations, or changes in DNA, that are passed on from parent to child. They calculate that of the three billion units in the human genome, 60 per generation are changed by random mutation — considerably less than previously thought.
That study is by Roach in Science magazine.
On genome-wide associational studies:
And in most diseases the culprit DNA was linked to only a small portion of all the cases of the disease. It seemed that natural selection has weeded out any disease-causing mutation before it becomes common. The finding implies that common diseases, surprisingly, are caused by rare, not common, mutations.
…implying we need to do more fine-grained studies of genomes. On the cost of whole genome sequencing:
The family whose genomes they report in Science were sequenced by a company with a new DNA sequencing method, Complete Genomics of Mountain View, Calif., at a cost of $25,000 each. Clifford Reid, the chief executive, said that the company was scaling up to sequence 500 genomes a month and that for large projects the price per genome would soon drop below $10,000. “We are on our way to the $5,000 genome,” he said.