8-year-old: Trouble breathing and loss of motor skills 

T was born following a normal pregnancy, labor and delivery. There were no concerns about T’s growth and development in their childhood. When T is in third grade, their parents start to notice that T is having trouble keeping up with the other kids when they play together. This includes running and using stairs. At home, T’s parents notice that they are breathing heavier, and with more strain. When they eat dinner together, T is taking longer to chew and swallow their food.

T’s parents took them to their primary care provider (PCP), as they were concerned about T’s breathing. Their PCP recommended respiratory therapy, which T was enrolled in and started shortly after. Although T learned how to better control their breathing and swallowing while eating, they did not start catching up to their peers in daily physical activities, and their breathing problems were being managed, but not resolved. T’s parents were recommended to see a neurologist, who recommended doing a blood creatine kinase (CK) test due to muscle weakness.

When the CK result came back, levels were elevated. T was referred to genetics, and the family was told that this could be due to a muscular dystrophy. When the family was seen by genetics, the team ordered a whole genome test, which is a comprehensive genetic test that looks at both nuclear and mitochondrial DNA. When the genetic testing results came back, T was found to have 2 altered copies of the TK2 gene.

T was diagnosed with a rare condition called early-onset thymidine kinase 2 deficiency (TK2d). With this diagnosis, T and their parents were able to enroll in clinical trials for TK2d, while also receiving therapies, such as physical therapy, occupational therapy, and chest physiotherapy.