Ingestion of a newly described North American mushroom species from Michigan resulting in chronic renal failure: Cortinarius orellanosus

Background. Some mushrooms in the genus Cortinarius are well known to cause acute and chronic renal failure. Until now, there have been no confirmed cases of renal failure due to the ingestion of a Cortinarius mushroom in North America. We describe a case of a woman who ingested mushrooms found under an oak tree in western Michigan and developed chronic renal failure. Methods. Phylogenetic analysis of the internal transcribed spacer (ITS) regions of nuclear-encoded ribosomal RNA was performed between an unconsumed sample of the Michigan specimens, a control sample of Cortinarius orellanus (JFA9859) from Europe, and other closely related ITS sequences of Cortinarius retrieved from GenBank. An additional gene region, rpb2, was also sequenced for comparison. Results. Phylogenetic analysis revealed the Michigan material to be closely related to, but distinct from, other ITS sequences of the Orellani clade in Cortinarius. Divergence is less at the rpb2 locus. No historical taxa from North America are known to match the identification of the Michigan material. Conclusion. The mushrooms ingested by the patient were confirmed to be a new species of Cortinarius closely related to C. orellanus. We introduce a newly described North American species, Cortinarius orellanosus, capable of causing renal failure after ingestion.