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PHELAN MCDERMID SYNDROME FOUNDATION

EIN 04-3673104 OSPREY, FL

Revenue 2025
$1,245,861
Expenses 2025
$1,082,374

Program services were 65.5% of total expenses calculated — Part IX's program-services column over total expenses, both as filed.

As filed

Subsection
03
NTEE code
H80
Classification
2000
Street
8 SORRENTO DR

These codes are the IRS's own and are shown exactly as filed. What each one means is in the Business Master File documentation (opens in a new tab).

Mission and programs · 2025

Mission

The mission of the Phelan-McDermid Syndrome Foundation is to make today better and the future brighter for everyone living with Phelan-McDermid syndrome - from the moment of diagnosis to the delivery of treatments and cures.

  • CONNECT (Family Support): The Organization (PMSF) connects with families from diagnosis throughout their life journey, providing essential support, knowledge, and skills to navigate the complexities of Phelan Mc-Dermid syndrome. In 2025, PMSF provided 2,400 connections through comprehensive support services, welcoming 300 new families into membership. Key initiatives included supporting 133 newly diagnosed families via the "First 100 Days" program, educating 250 caregivers and professionals through the "Pathways" video series, and facilitating 48 Caregiver Support Group sessions for 250 participants. These programs integrate mental health, social, and emotional well-being, while regional and international gatherings further empower our community to thrive.

    Expenses $192,052

  • CARE (Improving Medical Care): The Organization (PMSF) ensures that individuals with Phelan-McDermid syndrome have access to a robust community of specialists and evidence-based care. We bridge the gap between research and clinical practice by educating professionals, facilitating medical consultation, and expanding our specialized clinical infrastructure. In 2025, we strengthened this ecosystem by establishing our first 11 Phelan-McDermid Syndrome Clinics-including a new multidisciplinary center at Cincinnati Children's Hospital Medical Center-and launched initiatives to grow our Healthcare Provider (HCP) network. Our experts facilitated 22 neuropsychiatric consultation cases, 15 neuropsychiatric referrals, and 50 genetic counseling referrals. Additionally, we served as a primary medical hub, recording over 100,000 views on pmsf.org and overseeing 3,500 downloads of clinical and educational resource documents.

    Expenses $168,860

  • Withheld by Nonprofiteer: this text may name a private individual.

    Expenses $348,155 · Grants $100,000 · Revenue $14,143

As filed on the 2025 return. A text marked withheld matched a screen for wording that may name a private individual, such as an honorific or "in memory of". Most of what it withholds names no one; it is withheld so that what does is never shown.

Officers and directors · 2025

As listed in Part VII of the 2025 return, in the order the filer printed them. Each return names its own; this is not a roster the organization keeps with us.

  • Diane Linnehan

    Chief Operating Officer/Co-interim CEO

    Total calculated
    $120,416
    From this org
    $117,089
    From related orgs
    $0
    Other
    $3,327
    Hours/week
    40

  • Lauren Schmitt

    Chief Science Officer

    Total calculated
    $111,366
    From this org
    $108,138
    From related orgs
    $0
    Other
    $3,228
    Hours/week
    40

  • Shira Johnson

    Chief Development Officer/Co-Interim CEO

    Total calculated
    $56,013
    From this org
    $54,382
    From related orgs
    $0
    Other
    $1,631
    Hours/week
    40

  • Priscilla Hackstadt

    Chief Financial Officer

    Total calculated
    $49,424
    From this org
    $48,022
    From related orgs
    $0
    Other
    $1,402
    Hours/week
    16

  • Rhonda Blumenthal

    Chief Executive Officer

    Total calculated
    $31,359
    From this org
    $30,446
    From related orgs
    $0
    Other
    $913
    Hours/week
    40

  • Denise Croden

    President

    Total calculated
    $0
    Hours/week
    5

  • Ben Holocher

    Vice President

    Total calculated
    $0
    Hours/week
    5

  • Lisa Brown

    Secretary

    Total calculated
    $0
    Hours/week
    5

  • Michael Cento

    Treasurer

    Total calculated
    $0
    Hours/week
    5

  • Catherine Valcourt-Pearce

    Director

    Total calculated
    $0
    Hours/week
    2

  • Rebecca Buchanan

    Director

    Total calculated
    $0
    Hours/week
    2

  • Eden Rivera

    Director

    Total calculated
    $0
    Hours/week
    2

  • Dr Lori Levi

    Director

    Total calculated
    $0
    Hours/week
    2

  • Heidi Grabenstatter PhD

    Director

    Total calculated
    $0
    Hours/week
    2

Compensation is as filed in Part VII: reportable pay from this organization and from related organizations, other compensation, and hours per week. The total, marked calculated, is our sum of the three dollar columns, with a blank column counted as $0; the form itself has no total. On a Form 990-EZ the columns are Part IV's instead, and on a Form 990-PF Part VIII's — compensation, contributions to benefit plans, and expense account — and the total sums those. Earlier years are each on their own filing page.

Filings

  • 2025
    Revenue
    $1,245,861
    Expenses
    $1,082,374
    Contributions
    $1,060,585
    Grants paid
    $105,000
  • 2024
    Revenue
    $1,306,884
    Expenses
    $1,437,564
    Contributions
    $1,084,905
    Grants paid
    $326,392
  • 2023
    Revenue
    $1,062,761
    Expenses
    $1,098,819
    Contributions
    $834,914
    Grants paid
    $222,500
  • 2022
    Revenue
    $853,648
    Expenses
    $715,263
    Contributions
    $744,192
    Grants paid
    $20,900

The four totals the IRS asks for on Part I of the Form 990, as filed. A dash means the figure was not present on the return — not that it was zero.

Other returns filed

  • 2021 · 990

    Revenue
    $897,002
    Expenses
    $497,424
    Assets (EOY)
    $1,940,384

  • 2020 · 990

    Revenue
    $560,200
    Expenses
    $455,390
    Assets (EOY)
    $1,639,670

  • 2019 · 990

    Revenue
    $656,384
    Expenses
    $578,555
    Assets (EOY)
    $1,427,059

  • 2018 · 990

    Revenue
    $1,199,078
    Expenses
    $899,420
    Assets (EOY)
    $1,423,117

  • 2017 · 990

    Revenue
    $1,162,999
    Expenses
    $1,119,265
    Assets (EOY)
    $1,197,242

  • 2016 · 990

    Revenue
    $1,272,080
    Expenses
    $1,046,066
    Assets (EOY)
    $1,193,813

  • 2015 · 990

    Revenue
    $1,137,997
    Expenses
    $925,135
    Assets (EOY)
    $1,047,572

  • 2014 · 990

    Revenue
    $911,724
    Expenses
    $862,908
    Assets (EOY)
    $826,825

  • 2013 · 990

    Revenue
    $452,384
    Expenses
    $284,482
    Assets (EOY)
    $562,228

  • 2012 · 990

    Revenue
    not reported
    Expenses
    $409,825
    Assets (EOY)
    $423,996

Nonprofiteer parses Forms 990, 990-EZ and 990-PF, in a window of recent tax years. These returns are recorded from the IRS e-file index, so their figures were extracted by that index rather than read from the return here — treat them as a different source from the filings above, not as more of the same record. A dash means the index carries no figure; Form 990-T listings carry none at all. Showing the 10 most recent; the API carries the rest.

Grants made

  • Boston Children's Hospital Children's Hospital Corporation

    $116,392

    2024 To support the conclusion of the second phase of the Developmental Synaptopathies Consortium's Phelan-McDermid syndrome natural history study, including Boston Children's Hospital personnel costs and subawards to Icahn Mount Sinai Medical Center and Rush University for personnel costs as well.

  • Children's Hospital Corporation DBA Boston Children's Hospital

    $100,000

    2023 To understand whether people with Phelan-McDermid syndrome, particularly those with severe neuropsychiatric illness (SNPI) -- have underlying differences in their immune system that might guide treatment.

  • Children's Hospital of Los Angeles

    $100,000

    2025 To identify diagnostic biomarkers in up to 30 individuals with Phelan-McDermid syndrome who present with neuropsychiatric disease. To determine whether these individuals exhibit distinct cytokine, proteomic, and metabolomic profiles in the serum and cerebrospinal fluid indicative of systemic and/or central inflammation. To evaluate markers of cortical and white matter disruption using magnetic resonance imaging and electroencephalography.

  • Seaver Autism Center Icahn School of Medicine at Mount Sinai

    $100,000

    2024 To fund the further development of the Phelan-McDermid syndrome Inventory for Psychiatric Symptoms (PIPS) tool, to better support individuals with Phelan McDermid syndrome and their caregivers with managing and intervening in neuropsychiatric episodes experienced by these individuals.

  • University of Miami

    $55,000

    2023 To develop an alternative objective measure of Gastrointestinal motility (GI transit) in individuals with Phelan-McDermid syndrome. Muffins with blue dye will be ingested by individuals with Phelan-McDermid syndrome and caregivers will use a mobile app to track and report GI transit time.

  • Northeastern University

    $55,000

    2024 To support a project seeking to expand a new natural communication sampling protocol called ROSCO (Rapid Online Sample of Communication). ROSCO is designed to elicit meaningful samples of communication from individuals with Phelan McDermid syndrome via online-video platforms like Zoom in approximately 15 minutes. This study will validate the ROSCO paradigm with the Phelan McDermid syndrome population longitudinally, using repeated samples to establish reliability and sensitivity to communication change over time.

  • Clemson University Foundation

    $55,000

    2023 To study the response of cells from individuals with Phelan-McDermid syndrome to candidate therapeutics/treatments (such as Insulin-like Growth Factor 1 and human growth hormone) and identify subgroups in the Phelan-McDermid syndrome population that will potentially respond better or worse to the selected compounds.

  • Icahn School of Medicine at Mount Sinai

    $20,900

    2022 To define and retrospectively characterize the neurobehavioral profile of individuals with Phelan-McDermid syndrome and neuropsychiatric decompensation. To develop clinician and caregiver survey tools for qualitative assessment of clinical outcomes based on recommendations from the Phelan-McDermid syndrome Neuropsychiatric Consultation Group.

  • Autism Science Foundation

    $10,000

    2023 To model neuroinflammation and neuropsychiatric regression in profound autism.

Where these grants went next →

Grants received

The 10 largest by cash amount. The API serves every itemized grant.

Other IRS files

Auto-Revocation List

Not listed. The IRS publishes this list for organizations whose exemption was automatically revoked for failing to file for three consecutive years.

Publication 78

Listed as of 13 October 2026, under deductibility PC.

These are two separate IRS files on two separate schedules, shown as published and not reconciled with each other. Neither is a statement about whether a contribution is deductible today: 19,245 organizations appear in Publication 78 while the IRS's own revocation file lists them as currently revoked, more than half of those revoked before 2019. Absence from Publication 78 is evidence of nothing, and presence is not evidence either. Verify current status with the IRS before relying on it.

What this page reflects

The registration facts above come from the IRS Business Master File published 13 October 2026 and read 26 October 2026, for every organization at once. Returns through tax year 2025, the newest we have parsed for this organization.