Desc: Rarefied: Directed by Wil Weldon. In a search for answers, nine families struggling with undiagnosed genetic conditions have their DNA sequenced. For decades, families with undiagnosed genetic diseases went from specialist to specialist as they searched in vain for answers. Now, thanks to DNA sequencing, it's possible to read the more than 20,000 genes in the human genome at once and to begin to find those answers. But what do they mean? How do they affect the way these families care for their children (and each other) and imagine their futures? Do they inspire hope or despair? Rarefied chronicles the difficult, unexpected and moving journeys of nine such families and explores both the power and limits of genetic knowledge.