Peirson Center for Children

01/08/2026

Dr. Peirson has written a new blog post, "Navigating a New Diagnosis of Down Syndrome", and it is the most personal and important piece she has written in her career.

This post was written for families at the very beginning of the journey. The moment when a diagnosis is new, emotions are raw, and information can feel overwhelming or conflicting. Drawing from both her lived experience as a parent and her clinical work supporting children with Down syndrome, Dr. Peirson offers a steady, grounded perspective on what this diagnosis truly means and what it does not.

The importance of this piece lies in how early narratives shape families’ understanding, expectations, and sense of hope. The way Down syndrome is first explained can deeply influence how parents view their child, their future, and their own confidence moving forward. This post is meant to counter fear-based messaging with clarity, context, and compassion.

Rather than focusing on what is “missing,” this blog emphasizes understanding the whole child, supporting development thoughtfully, and recognizing that families are not alone in this process. It reflects the philosophy that guides our entire team in their clinical work and their commitment to walking alongside families with honesty and respect.

We encourage families, practitioners, and anyone supporting new parents to read and share this piece.

https://www.peirsoncenter.com/articles/navigating-a-new-diagnosis-of-down-syndrome

01/02/2026

At this time, Dr. Peirson will be temporarily suspending the acceptance of new patients so she can focus on the care of existing patients, ongoing clinical work, and dedicated writing projects.

We are grateful for the continued trust in our practice and want families to know that excellent care remains available. New families are welcome to work with Dr. LaRosa or Dr. Ast, both of whom are highly qualified clinicians and work closely with Dr. Peirson as part of our collaborative care team. Care plans are aligned, cases are discussed together, and our shared philosophy of thoughtful, individualized care remains the same.

If you would like to apply to work with our team to help support your child with complex medical and developmental needs, you may do so here:
https://www.peirsoncenter.com/new-patient-application.html

12/30/2025

✨ New blog post ✨

Dr. Peirson has finally written about an issue that comes up again and again in the children we serve, yet is often misunderstood: zinc status.

Zinc plays a critical role in immune health, gut integrity, growth, appetite, and neurodevelopment, but low or functionally inadequate zinc is common in children with Down syndrome and autism. Even more challenging, standard lab results don’t always tell the full story.

In this post, Dr. Peirson breaks down:
• why zinc matters so much for developing kids
• how to interpret zinc and copper labs more accurately
• why “normal” is not always the same as optimal
• how absorption, inflammation, and balance affect zinc status

If zinc has ever come up in your child’s labs, supplements, or care plan, this is a must-read.

https://www.peirsoncenter.com/articles/understanding-zinc-status-in-children-diet-labs-and-clinical-clues

Link in profile.

12/08/2025

This is progress. It reflects a much-needed shift toward individualized care and the recognition that medical choices should never be one-size-fits-all. No pharmaceutical product is universally safe or necessary for everyone, and honoring that truth creates space for more informed consent, informed decision-making, and respect for patient autonomy.

11/18/2025

Why does folinic acid need to be given in high doses when folate receptor antibodies (FRA) are present?

It comes down to two things:
affinity (how strongly a receptor attracts folate)
and density (how many of those receptors exist in the area that transports folate into the brain).

1. Folate Receptor Alpha (FRα)

FRα is located on the apical (top) membrane of the choroid plexus, the gateway responsible for transporting folate into the cerebrospinal fluid (CSF).

FRα has:
🔸 Extremely high affinity for methylfolate (a very strong magnet)
🔸 High receptor density - meaning lots of these receptors are packed tightly on the choroid plexus surface
🔸 A direct route into the CSF

But when folate receptor antibodies are present, they block or disable this entire high-affinity, high-density transport system.

When FRα is blocked, the brain loses its main entry door for folate.

2. Reduced Folate Carrier (RFC)

RFC provides a secondary pathway, but it’s nowhere near as efficient.

RFC has:
🔹 Very low affinity for folate (a weak magnet)
🔹 Much lower density compared to FRα at the blood-CSF barrier
🔹 A location that is not well-positioned for transporting folate into the CSF (mainly basolateral side of choroid plexus + neurons/glia)

This means RFC is open, but it’s not strong enough or abundant enough to transport folate into the brain at normal physiological levels. It’s like the side door to the brain - narrow, inefficient, and not designed for the main flow of folate.

So why high-dose folinic acid?

Because with FRα blocked:

➡️ Only the low-affinity RFC pathway is left
➡️ RFC cannot “grab” folate unless blood levels are extremely high
➡️ High-dose folinic acid floods the system
➡️ Allowing a small amount to pass through RFC and reach the brain

This is why children with FRA often need high-dose folinic acid, sometimes 1-2 mg/kg or more, to restore healthy folate levels in the CNS.

11/17/2025

🌟 New Blog Post! 🌟
“From Food to Brain: The Long Journey of Vitamin B12”

Vitamin B12 plays a key role in your child’s energy, development, behavior, and brain health, yet most people don’t realize how complex its path is inside the body. Even when a child eats well or has “normal” labs, B12 may not be getting where it needs to go.

In this new article, I walk through:
✨ The two critical enzymes that rely on B12
✨ Signs and symptoms of deficiency in children
✨ Every barrier B12 has to cross - from digestion to the brain
✨ Why serum levels don’t tell the whole story
✨ The most accurate tests to evaluate B12 status
✨ The connection between folate and B12
✨ How to support healthy B12 delivery in the body

If you have a child with Down syndrome, autism, developmental delays, fatigue, speech challenges, or neurological symptoms - this one is especially for you. 💛

Read the full post here:

https://www.peirsoncenter.com/articles/from-food-to-brain-the-long-journey-of-vitamin-b12

11/14/2025

Dr. LaRosa and Dr. Peirson are attending the LymeBytes Symposium virtually this weekend, and the lectures so far have been absolutely fascinating and deeply clinically relevant.

They’re always learning, always evolving, and always looking for new ways to better support their patients, especially those navigating complex chronic infections, immune dysregulation, and neurodevelopmental challenges.

Staying on the cutting edge of research helps us bring the most thoughtful, evidence-informed care back to our families.

If you're curious about the event, you can learn more here:

LymeBytes!™

11/12/2025

🌿We’re thrilled to welcome Dr. Hayleigh Ast, ND to the Peirson Center for Children! 🌿

👩‍⚕️Dr. Ast brings a deep dedication to helping children and young adults reach their fullest potential through integrative, evidence-based care. Her clinical focus includes supporting children with Down syndrome, autism, ADHD, and other neurodevelopmental conditions, always honoring the powerful connection between the brain, body, and gut.

🩺Dr. Ast trained under Dr. Erica Peirson, an experience she describes as profoundly impactful in shaping her approach to pediatric neurodevelopment and functional medicine. Through this mentorship, she gained advanced understanding of mitochondrial health, methylation, and the biochemical individuality of children with Down syndrome and autism, foundations she now brings to her own clinical practice.

🧒She is especially passionate about addressing the impact of diagnostic overshadowing, where medical or behavioral concerns are too often overlooked or attributed solely to a diagnosis. Dr. Ast is committed to seeing the whole child, their strengths, challenges, and unique biology, to uncover what truly supports their growth and thriving.

🔬A licensed naturopathic physician and post-doctoral fellow at Oregon Health & Science University, Dr. Ast has contributed to multiple peer-reviewed studies on the gut-brain-immune axis and micronutrient therapies for ADHD and other pediatric conditions.

✨ Dr. Ast will begin seeing patients in early December! We’re honored to have her join our team and continue advancing our mission of empowering families and supporting children to truly thrive now and into the future. 💛💙

11/03/2025

Not all folate is the same.

Folate is an umbrella term for a family of vitamin B9 compounds that drive critical reactions in the body, including DNA synthesis, methylation, detoxification, and neurotransmitter production.

🟩 Methylfolate (5-MTHF) - This is the biologically active form of folate. It donates methyl groups to convert homocysteine to methionine, fueling the SAMe cycle that powers methylation of DNA, neurotransmitters, and phospholipids. Methylfolate also supports BH4 regeneration, a cofactor essential for producing dopamine, norepinephrine, and serotonin. People with MTHFR variants (C677T or A1298C) often rely more heavily on supplemental methylfolate.

🟨 Folinic Acid (5-formyl-THF, or Leucovorin) - A naturally occurring, metabolically active form that does not require MTHFR for conversion. It readily converts to 5,10-methylene-THF, supporting purine and pyrimidine synthesis, the building blocks of DNA and RNA. Folinic acid can cross the blood–brain barrier even in the presence of folate receptor antibodies, making it especially important for individuals with FRα autoimmunity or cerebral folate deficiency.

🟦 Folic Acid - The synthetic, oxidized form used in fortified foods and many supplements. It must be converted to dihydrofolate (DHF) and then tetrahydrofolate (THF) by the DHFR enzyme, which has limited activity in humans. When intake exceeds conversion capacity, unmetabolized folic acid (UMFA) can accumulate in the blood and may interfere with natural folate transport or immune signaling.

These biochemical distinctions explain why one form of folate doesn’t fit everyone. Supporting the right step of the pathway can optimize methylation, cognition, and cellular repair, especially for those with MTHFR variants or folate receptor antibodies.

© Infographic by Peirson Center for Children

www.peirsoncenter.com

10/31/2025

As Down Syndrome Awareness Month wraps up, let’s take a closer look at just how much extra genetic material is involved in Down syndrome and what that really means.

Chromosome 21 makes up only about 1.5-2% of all the genetic material that makes us who we are. The region on chromosome 21 that is most associated with the key traits of Down syndrome, called the Down Syndrome Critical Region (DSCR), accounts for roughly 37% of that chromosome.

That means this critical region represents just 0.56-0.74% of the entire human genome. So while chromosome 21 adds a little extra, the other 99.2-99.5% of their DNA carries everything that makes them unique and far more like their own family than like anyone else with Down syndrome.

Although this small stretch of DNA has far-reaching implications, it doesn’t explain everything we see in our loved ones with Down syndrome. The way these genes are expressed varies widely among individuals and across different tissues. Other genes, regulatory feedback, and environmental influences all interact to shape each person’s development, health, and abilities. Understanding this complexity reminds us that genetics is never one-dimensional, and that the potential within every person with Down syndrome is truly endless.



www.peirsoncenter.com

10/30/2025

As Down Syndrome Awareness Month comes to a close, we're reflecting on what makes every individual truly unique - not just in personality, but in biology.

Not every person with Down syndrome looks, develops, or responds to interventions the same way and science helps explain why.

Research shows that the effects of trisomy 21 are shaped by each person’s unique genetics and environment. Other inherited alleles and external influences modify how those extra genes are expressed, creating a wide range of outcomes across individuals.

🧬Beyond Trisomy 21: Phenotypic Variability in People with Down Syndrome Explained by Further Chromosome Mis-segregation and Mosaic Aneuploidy
https://pmc.ncbi.nlm.nih.gov/articles/PMC5837063/

Even within the same person, gene expression differs from tissue to tissue. It isn’t a simple 1.5× increase in activity for every triplicated gene. Expression is regulated by complex feedback systems that adjust levels dynamically.

🔬 The importance of understanding individual differences in Down syndrome
https://pmc.ncbi.nlm.nih.gov/articles/PMC4806704/

Recognizing this variability helps us avoid diagnostic overshadowing, the tendency to attribute every medical or behavioral concern to the diagnosis itself. When we look deeper, we see opportunities for personalized care that supports every child and adult with Down syndrome to truly thrive.



www.peirsoncenter.com

10/23/2025

🔍 Common Myths About Folinic Acid (Leucovorin)

Let’s clear up a few myths about folinic acid (leucovorin). We see a lot of confusion online, especially mixing it up with MTHFR, methylfolate, or general ‘folate support.’ In reality, this therapy is specifically aimed at restoring brain folate transport in children who have blocking antibodies to folate receptors.

“It’s for MTHFR mutations.”
Fact: Folinic acid doesn’t correct MTHFR enzyme issues. Its role is to bypass blocked folate receptors and restore folate transport into the brain. The MTHFR gene affects methylation of folate inside cells, while folate receptor antibodies block brain uptake. They’re two completely different pathways.

“It’s the same as methylfolate.”
Fact: Folinic acid and methylfolate are completely different molecules. Folinic acid supports intracellular folate cycling and brain folate transport, while methylfolate donates methyl groups in cytosolic methylation reactions.

“Everyone with autism or Down syndrome needs it.”
Fact: Only those with folate receptor alpha autoantibodies (FRAA) or signs of cerebral folate deficiency truly benefit. It’s not a one-size-fits-all therapy.

“It’s a vitamin, so you can’t overdo it.”
Fact: Folinic acid acts pharmacologically at high doses. The research doses (1-2 mg/kg/day up to 50-100 mg/day) are therapeutic, not nutritional, have the potential for significant side effects and should be monitored by an experienced physician.

“It’s safe to start on your own.”
Fact: Dosing and tolerance vary widely. Some children become more stimulated, anxious, or aggressive initially, so experienced medical guidance is essential.

“If it didn’t work at a low dose, it won’t help.”
Fact: Many clinical responses occur only at higher, physician-managed doses (up to 2 mg/kg/day or more), especially in FRAA-positive cases.

“You don’t need testing - just try leucovorin and see.”
Fact: While some children respond clinically, testing matters. Knowing whether folate receptor antibodies are present helps determine if brain folate transport is blocked and whether high-dose folinic acid is likely to help. It also avoids unnecessary or confusing supplement trials.

“A negative FRAT result means folinic acid won’t help.”
Fact: Not necessarily. Some children test negative but still respond, likely due to other transport or mitochondrial issues. However, a positive result strengthens the rationale for treatment.

“Leucovorin works on its own. You don’t need anything else.”
Fact: Many children do better when leucovorin is paired with key cofactors such as B12, lithium, and calming supports to help mitigate potential side effects.

Used correctly and under medical supervision, leucovorin can be transformative for language and cognition in some children, but it’s not for everyone. It’s powerful, precise, and should always be guided by testing and clinical context.