A weak earnings forecast driven by disappointing sales in Europe hammered shares of San Diego-based Illumina Inc. during trading Tuesday and Wednesday.

The firm, which makes DNA sequencing machines, watched its stock drop more than 23 percent on Tuesday, and it made only a 2 percent gain the following day. The fall was the company’s biggest one-day price loss in the 16 years since it went public.

The firm dropped its 2016 revenue growth forecast from 16 percent to 12 percent in a first-quarter earnings call late Monday. Revisions to the forecast, which included lower-than-expected revenue of $572 million in Q1, were attributed to troubles in the European market and unexpected upgrades to the company’s sequencing platforms.

The forecast was disappointing to shareholders, considering the company’s seemingly unstoppable growth so far this year. The company has announced a string of developments since January, including multiple collaborations, a new product launch (MiniSeq), and the Grail spinout, a cancer detection company backed by a $100 million Series A round and led by ex-Google executive Jeffrey Huber. Then in March, the company’s longtime CEO Jay Flatley retired, handing the reins to Francis deSouza, an executive Illumina hired from Symantec Corp. in 2013 and who has long been seen as Flatley’s heir apparent.

Earlier this month, Illumina announced that it had leased the entire 316,000-square-foot BioMed Realty i3 campus, currently under construction at University Town Center. The new facility is an expansion, as Illumina intends to retain its current significant current presence in UTC.