GlaxoSmithKline ($GSK) was rumored to be interested in Human Genome Sciences ($HGSI) for several years before it actually got down to a brass-knuckles bid for its longstanding biotech partner. Now The Telegraph in the U.K. is reporting that the market buzz indicates that GSK is in talks with BioMarin ($BMRN), the rare disease drug outfit that has been snapping up programs in recent months. And the GSK gossip follows a rumor that Shire ($SHPGY), which has its own rare disease drug portfolio to consider, could be in the hunt for BioMarin. Rare diseases have been growing steadily more attractive to developers over the past few years. But none of this rises to the level of insider info, which helps explain why the biotech's stock is only up less than three percent this morning. Report