Pyridoxine Dependent Epilepsy

Jack is so many things. He’s capable, he cute as a button, he’s smart and he’s stubborn, he’s affectionate, he’s friendly, and he means so much to many people. But, before I even got to the chance to know and love my son, I was given a limit on his life and a limit on my time with him. With a life-limiting + incorrect diagnosis and poor prognosis, my 11-week-old was in a fight for his life. You would never believe it looking at my big healthy boy today, but he almost wasn’t here. He has a rare disease that was almost missed.

Jack saw over 20 different doctors–specialties like Neurology, Human Genetics, Infectious Disease, ect.–in one of the US’ leading Children’s hospitals. Jack’s rare disorder, known as Pyridoxine Dependent Epilepsy(PDE), was overlooked for 6 solid months while he struggled and suffered with intractable seizures and a subsequent brain injury. This slow struggle towards a correct diagnosis is not uncommon in the rare disease community, and in fact, Jack was diagnosed quickly for having a rare disease. According to Global Genes (my go-to for all things rare and genetics related), the average time it takes for a rare disease patient to get a correct diagnosis is 4.8 years. My son could not have survived this long without the correct diagnosis + treatment and that is why I tell as many people as will listen. Awareness is everything in the rare disease community, especially when there is a treatment that is absolutely life saving like Triple Therapy for PDE.

I was thrilled when I was told we would be swapping out (slowly of course) 5 different AEDs (Phenobarb, Keppra, Topamax, Fospheny, AND the regular use of diazepam) for Pyridoxine (B6) and a new diet. For my non-neuro friends, I used the “pet words” for some of the AEDs (Anti-Epilepsy Drugs) because it’s one way we exert a little control over the meds. (ha!) WHAT? Is this even real? We went from absolute devastation, being told that our infant son had mitochondrial disease and his brain would “continue to atrophy until he passed away” to he has an Inborn Error of Metabolism and needs to see Genetics and a Metabolic Nutritionist ASAP. So he is going to live? YES! I learned the hardest way possible that doctors are not always right; they do not get to write the story of your child’s life and the fight is always worth it! I know many readers already know the entire story, but the Mito diagnosis was Jack’s second misdiagnosis. When he was just 10 days old and in the PICU after being life-flighted, we were told that he had a Hypoxic Ischemic Encephalopothy (HIE). There were pieces of Jack that fit with each diagnosis at the time so the neuro team did what they could with the information available at the time. However, the information could and should be better for inborn errors in metabolism (like PDE) that can be tested and added to the newborn screening process. As the mother of a kiddo with a rare disease, I can tell you caregivers fight, scrap, and claw for every inch of information that will help our children. And the battle is always worth it.

All of this being said, I have learned SO MUCH about PDE and want to give an update on Jack Jack. This has taken me so long for a few reasons: I want to thoughtfully explain PDE in a way that does the patient’s justice AND this update involves a subject that makes me most uncomfortable–intellectual disability. We have been prepared for many things with Jack; from the beginning we were prepared for a severely brain-injured child with a completely unpredictable future, next we were prepped (by doctors) for our son to die, then we were told his true diagnosis and prepared for unpredictable delays. Whew! I’m grateful for, not disheartened by, these diagnoses now because they made me fight like hell for my son. Jack is now 2.5-years-old and will be 3 in July. He has carried and still carries many of these diagnoses: PDE, ASD, Apraxia, SPD, GDD, Hypotonia, CP, etc. Last month Jack had two major appointments that really helped me understand, come to terms if you will, with what my son’s diagnosis of PDE truly means (at least for him, each child is so different). Here’s the medical portion: Jack is sometimes (hopefully not all the time) having seizures while he sleeps. His EEG tells his neurologist that is brain is processing at a little bit of a slower pace than typical kiddos while he is awake.

These were both things I was unprepared to hear. Jack is currently on 300mg of Pyridoxine, which is a lot considering the main side effect is peripheral neuropathies. Most people need only 2mg of B6 per day just to put that in perspective. Jack is actually doing quite well currently and on an upswing with development so we aren’t interested in adding an AED at this time. My main question that I kept coming back to was, “will Jack have an intellectual disability?” I don’t know why I didn’t really prepare myself for this portion of Jack’s disorder; after all, it is written quite clearly that PDE patients are likely to have a learning disability. The idea of the gap between Jack and his peers widening absolutely crushes my heart, but I don’t have much time to mourn so on we go! Another interesting development in Jack’s diagnoses is that both the child psychologist and neuro-development team that Jack saw do NOT think Jack has ASD.

They said that Jack has some very severe delays, most severe being his gross motor skills. They said that Jack struggles to orient himself with other people because it’s all he can do to hold himself up. He does not make good eye contact because his neck and core are so weak. He wants to make eye contact, they say, but it’s just too difficult because he is so big, yet his tone is so low. Sometimes he just looks like all his parts don’t work together quite right, but it’s what make him Jack Jack! Needless to say, these appointments have clarified and sharped so many things for me.

Jack’s incredible neurologist, Dr. Koh of Children’s Healthcare of Atlanta, told me that while many of those above diagnoses apply to Jack clinically, he doesn’t need them in addition because he has the “unifying diagnosis” of Pyridoxine Dependent Epilepsy. PDE, she explained, is a “metabolic encephalopothy”. What the hell does that mean? It means that Jack’s brain works differently at the metabolic level, causing him to develop differently than neuro-typical children. When this “metabolic encephalopthy” was not being properly treated, it caused damaged to Jack’s brain.

The damage, or what they like to the “dull spot” on Jack’s MRI explains his ataxia, but PDE explains everything else. PDE is rare so there isn’t much written, not many resources to compare, and not enough kids diagnosed and treated properly to predict what Jack’s future looks like. I know all the rare patient caregivers can relate to that. Interestingly, Jack’s doctors (not just Dr. Koh) say that PDE is really the only diagnosis Jack needs because PDE implies developmental delays, epilepsy, hypotonia, etc. While I have always understood this, I have also spent so much of my time fighting with insurance for early intervention services and keeping ER doctors from killing my son because PDE isn’t an instantly recognizable diagnosis.

An insurance representative once said to me, “I don’t understand why your son needs so many therapies, it’s not like he has Down Syndrome or something”. I hung up immediately so my anger for my son and then my friends and loved ones with Down Syndrome didn’t vaporize him through the phone. Maybe, hopefully it still did. Dr. Koh basically told me that it’s my job to change this and make people recognize and remember PDE. So remember this: PDE is super similar to PKU and both can kill you if not properly treated.

BY METABOLIC MAMA

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