Eye of the Tiger

I never really liked the song, but now I really don’t. 

People with PKAN present with the “eye of the tiger” sign during a T2-weighted MRI.  Looking at the image of the brain, it resembles the face of a tiger.  The “eye of the tiger” sign refers to generally symmetrical bilateral white areas (due to accumulation of iron) in the medial aspect of globus pallidus of the brain. (See Chaw-Liang Chang and Chih-Ming Lin, Eye-of-the-Tiger sign is not Pathognomonic of Pantothenate Kinase-Association Neurodegeneration in adult cases, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3217674/).   There is a one-to-one correlation (94% chance) that if you are a child that has an MRI evidencing the eye of the tiger sign, you have PKAN.  A T2-weighted MRI is the most common way PKAN is diagnosed. 

Loic had an MRI in May 2022 that was generally unremarkable. In Bozeman, we don’t have the T2 technology available so the MRI did not show the eye of the tiger sign.  What it did show was delayed myelination and fluid on Loic’s adenoids.  Because he was only 18 months old, it was hard to say if his myelination development was delayed, so we planned to repeat the MRI when he turned 3. 

Prior to receiving the genetic test results, we had another MRI to assess his tongue tremor we recently discovered. After we learned about his PKAN diagnosis, we had to reschedule the MRI in Billings to get the proper imaging. 

I waffled many times as to whether we should follow through with the MRI now that we have a confirmed genetic diagnosis.  Putting him under anesthesia is scary, and I worried about the impact of it on his already delicate brain. Confirmation of the MRI image doesn’t change his diagnosis, prognosis, or treatment.  No matter what the MRI looks like, there still is no cure or treatment for PKAN.  No matter what the MRI looks like, his symptoms are his symptoms.  

We ultimately decided to do the MRI so we could make sure there wasn’t anything else that could make this situation worse – a tumor, an abnormality, a brain injury.  That was one of the reasons I pressed for the MRI last year. Having the MRI image to confirm the PKAN diagnosis may also help us get into clinical trials in the future.  

Truthfully, mom heart was also holding out hope that maybe the eye of the tiger sign wouldn’t be there. Maybe Loic doesn’t have PKAN.  Maybe the genetic test was wrong. It wasn’t. 

Loic did great during the MRI and woke up from anesthesia unlike most kids – happy.  When I finally saw MRI image it was a tiger staring right at us.  We knew this is what it would be. Even so, seeing it with my own eyes broke my heart a hundred times more.  Loic has scored 3 out 3.  Symptoms associated wit PKAN, including bad balance and difficulty speaking – check.  An affirmative gene mutation (not a variation of insignificance) in his PANK2 gene, with Mark and I both carrying a bad one – check, check.  An MRI showing the eye of the tiger sign in his little, tiny brain – check, check, check.  Is now when I’m supposed to accept that he has PKAN? 

Photo: T2 MRI on June 12, 2023.  While left side is circled, the same accumulation is seen on the right side as well.