Mistakes happen. Inside every cell, the functions of life rely on the basic process of building proteins. But, about half the time, cells make errors when building proteins and have to recycle the pieces and start again. One important player in the cell’s recycling process, an enzyme called N-glycanase 1 (NGLY1), is at the center of a new, fundamental biological mystery that researchers at The Children’s Hospital of Philadelphia are setting out to solve.

Two young patients brought this mystery to the team’s attention. Both children arrived within a short time of each other with symptoms of suspected mitochondrial disease at CHOP’s Mitochondrial-Genetic Disease Clinic, which Marni Falk, MD, directs. Mitochondria are the organelles inside of cells that act as the cell’s energy generator, and diseases of mitochondria can have wide-ranging effects across every organ system and commonly include neurological and cardiac complications.

“There are a lot of areas of mitochondrial biology that are still not known at all,” said Dr. Falk, an attending physician at CHOP. “We’ve been so intrigued with this project because, every time we asked a question, three more questions followed.”

Dr. Falk and her team found that, instead of a primary mitochondrial disease, these two children had an extremely rare genetic disorder that was only recently identified, caused by an inherited deficiency in the protein-recycling enzyme, NGLY1. This was fundamentally weird. There was no evident logical reason for a disease of NGLY1 dysfunction to so closely resemble diseases of mitochondrial dysfunction because the proteins in mitochondria do not require NGLY1’s services, or so says conventional wisdom.