What Is Phelan-McDermid Syndrome?

Phelan-McDermid Syndrome (PMS) is a rare genetic condition caused by a deletion or disruption of the SHANK3 gene on chromosome 22. The SHANK3 gene plays a critical role in brain development and synaptic functioning, which helps explain the neurological and developmental features associated with the syndrome.

PMS is considered a rare disorder, estimated to affect approximately 1 in 20,000–25,000 individuals, though it is likely underdiagnosed. It is one of the more common single-gene causes associated with autism spectrum disorder.

Common Characteristics

Phelan-McDermid Syndrome can look different from person to person, but individuals may experience a combination of:

  • Global developmental delays

  • Minimal or absent speech

  • Autism spectrum characteristics

  • Low muscle tone (hypotonia)

  • Motor planning and coordination challenges

  • Sensory processing differences

  • Intellectual disability (ranging in severity)

  • Sleep disturbances

  • Gastrointestinal concerns

  • Seizures (in some individuals)

Importantly, behavior is communication, and many individuals with PMS communicate in ways that are non-verbal, subtle, and deeply relational. Understanding these forms of communication is essential for meaningful support.

A Strength-Based Perspective

While PMS is often described clinically by challenges, individuals with Phelan-McDermid Syndrome are also known for their unique ways of connecting, strong sensory preferences, and meaningful relationships with trusted caregivers. Support is most effective when it is individualized, respectful, and grounded in both science and compassion.

Because PMS is rare and complex, families often benefit from collaborative, interdisciplinary support that honors lived experience alongside evidence-based practice.

Learn More About Phelan-McDermid Syndrome

Whether you’re newly learning about Phelan-McDermid Syndrome or looking to deepen your understanding, the following trusted resources offer education, research updates, and community support.

Honoring Ethan Wall & the Legacy That Guides My Work

My commitment to supporting families affected by Phelan-McDermid Syndrome (PMS) is rooted in relationships that shaped both my professional path and my life in lasting ways.

Ethan Wall: A Life That Continues to Guide My Work

In my early years in the field of Applied Behavior Analysis, I had the profound honor of working as a Registered Behavior Technician (RBT) with Ethan Wall. For three years, I had the privilege of knowing, supporting, and loving Ethan.

Ethan was not simply a client—he was a teacher. Through our time together, he shaped how I understand behavior, communication, dignity, and care. He taught me to prioritize connection over compliance, to remain flexible and humane in my clinical work, and to always see the person beyond the diagnosis.

In 2022, Ethan tragically passed away due to complications from Phelan-McDermid Syndrome. His loss was devastating and deeply felt.

After Ethan’s passing, I began journaling as a way to process my grief. What started as private reflection gradually became something more. That journaling evolved into my first book—a memoir written in his honor, reflecting on our journey together, the lessons he taught me, and the profound impact he continues to have on my life and work.

This book was not written as a clinical text, but as an act of remembrance, healing, and meaning-making. It represents my commitment to carrying Ethan’s voice, humanity, and legacy forward.

Legacy, Connection & Continued Learning

Through Ethan’s legacy, I was later introduced to Miles—a connection that further deepened my understanding of PMS beyond professional training alone.

Becoming a personal caregiver for Miles expanded my role from clinician to lived experience. Through this relationship, I gained firsthand medical knowledge and practical insight into:

  • The complex and evolving nature of PMS

  • Navigating medical systems and interdisciplinary care

  • Supporting fluctuating needs over time

  • Holding space for both grief and growth within families

Miles’ journey reinforced what Ethan first taught me: PMS is not linear, predictable, or easily defined. Meaningful support requires flexibility, humility, and deep respect for each family’s lived experience.

Carrying This Work Forward

Ethan and Miles are inseparable chapters of my story. Ethan’s life and legacy led me to Miles, and together they shaped the clinician, caregiver, advocate, and human I am today.

Because of them, I approach PMS families with:

  • Deep humility and respect

  • An understanding of loss, resilience, and transformation

  • A commitment to care that honors the whole person and the whole family

This work is personal. It is intentional. And it is grounded in both professional expertise and lived love.

When I support PMS families, I do so with the awareness that every journey is unique—and that every individual deserves care that sees them fully.

 

Sadie and Book E Man: Remembering Ethan Wall

Ethan Wall 2019

Miles Curtis smiling at Sadie’s cup that has pictures of Ethan Wall on it.

What Makes Me Qualified to Support PMS Families

  • Board Certified Behavior Analyst (BCBA) with training in evidence-based, ethical, and neurodiversity-affirming practice

  • Early clinical experience as an RBT supporting an individual with PMS across multiple settings

  • Personal caregiver experience, providing hands-on medical care, coordination with healthcare providers, and daily problem-solving beyond clinical environments

  • Deep familiarity with the evolving and unpredictable nature of PMS, including regression, medical complexity, and shifting support needs

  • Lived understanding of grief, resilience, and growth, shaped by loss, caregiving, and long-term relationships within the PMS community

  • Strong commitment to collaboration, honoring caregiver expertise and prioritizing quality of life, dignity, and sustainability

My approach blends clinical knowledge with lived insight. I support PMS families with flexibility, humility, and deep respect for the complexity of this journey—meeting families where they are and walking alongside them as needs change.

PMS Support vs Traditional ABA Approaches PDF

How PMS Support Is Different

Supporting individuals and families affected by Phelan-McDermid Syndrome (PMS) requires an approach that is flexible, responsive, and deeply individualized.

Unlike more predictable developmental profiles, PMS often involves:

  • Fluctuating skills and periods of regression

  • Complex medical needs that impact behavior, learning, and regulation

  • Significant variability across individuals and across time

  • Nonlinear progress, where traditional benchmarks may not apply

Because of this, effective PMS support must go beyond standard behavior programming.

My approach emphasizes:

  • Ongoing reassessment and adaptation, rather than fixed plans

  • Close collaboration with caregivers and medical teams

  • Support for communication, regulation, and quality of life, not just behavior reduction

  • Compassionate pacing, recognizing caregiver capacity and emotional load

  • Respect for grief and uncertainty, alongside hope, growth, and meaningful connection

PMS support is not about pushing progress—it is about building sustainable systems of care that honor the individual, the family, and the realities of this syndrome.