﻿<?xml version="1.0" encoding="utf-8"?>
<Return xmlns="http://www.irs.gov/efile" returnVersion="2024v5.0">
  <ReturnHeader binaryAttachmentCnt="0">
    <ReturnTs>2025-03-23T19:29:54-04:00</ReturnTs>
    <TaxPeriodEndDt>2024-12-31</TaxPeriodEndDt>
    <PreparerFirmGrp>
      <PreparerFirmName>
        <BusinessNameLine1Txt>GP Accounting Services</BusinessNameLine1Txt>
      </PreparerFirmName>
      <PreparerUSAddress>
        <AddressLine1Txt>2776 E Mcloughlin Blvd</AddressLine1Txt>
        <CityNm>Vancouver</CityNm>
        <StateAbbreviationCd>WA</StateAbbreviationCd>
        <ZIPCd>98661</ZIPCd>
      </PreparerUSAddress>
    </PreparerFirmGrp>
    <ReturnTypeCd>990EZ</ReturnTypeCd>
    <TaxPeriodBeginDt>2024-01-01</TaxPeriodBeginDt>
    <Filer>
      <EIN>020622876</EIN>
      <BusinessName>
        <BusinessNameLine1Txt>Costello Syndrome Family Network</BusinessNameLine1Txt>
      </BusinessName>
      <InCareOfNm>% Robert Hefner</InCareOfNm>
      <BusinessNameControlTxt>COST</BusinessNameControlTxt>
      <PhoneNum>8482482736</PhoneNum>
      <USAddress>
        <AddressLine1Txt>PO Box 1327</AddressLine1Txt>
        <CityNm>Black Mountain</CityNm>
        <StateAbbreviationCd>NC</StateAbbreviationCd>
        <ZIPCd>28711</ZIPCd>
      </USAddress>
    </Filer>
    <BusinessOfficerGrp>
      <PersonNm>ROBERT HEFNER</PersonNm>
      <PersonTitleTxt>Treasurer</PersonTitleTxt>
      <PhoneNum>8482482736</PhoneNum>
      <SignatureDt>2025-02-21</SignatureDt>
      <DiscussWithPaidPreparerInd>false</DiscussWithPaidPreparerInd>
    </BusinessOfficerGrp>
    <IRSResponsiblePrtyInfoCurrInd>true</IRSResponsiblePrtyInfoCurrInd>
    <PreparerPersonGrp>
      <PreparerPersonNm>GEOFFREY PLEAT</PreparerPersonNm>
      <PTIN>P00495985</PTIN>
      <PhoneNum>2068495839</PhoneNum>
      <PreparationDt>2025-03-23</PreparationDt>
      <SelfEmployedInd>X</SelfEmployedInd>
    </PreparerPersonGrp>
    <TaxYr>2024</TaxYr>
    <BuildTS>2025-03-06 01:10:19Z</BuildTS>
  </ReturnHeader>
  <ReturnData documentCnt="4">
    <IRS990EZ documentId="IRS990EZ">
      <MethodOfAccountingCashInd>X</MethodOfAccountingCashInd>
      <ScheduleBNotRequiredInd>X</ScheduleBNotRequiredInd>
      <WebsiteAddressTxt>http://costellosyndromeusa.com/</WebsiteAddressTxt>
      <Organization501c3Ind referenceDocumentId="990A">X</Organization501c3Ind>
      <TypeOfOrganizationCorpInd>X</TypeOfOrganizationCorpInd>
      <GrossReceiptsAmt>85129</GrossReceiptsAmt>
      <InfoInScheduleOPartIInd>X</InfoInScheduleOPartIInd>
      <ContributionsGiftsGrantsEtcAmt>85129</ContributionsGiftsGrantsEtcAmt>
      <TotalRevenueAmt>85129</TotalRevenueAmt>
      <SalariesOtherCompEmplBnftAmt>18062</SalariesOtherCompEmplBnftAmt>
      <FeesAndOtherPymtToIndCntrctAmt>2495</FeesAndOtherPymtToIndCntrctAmt>
      <OccupancyRentUtltsAndMaintAmt>4837</OccupancyRentUtltsAndMaintAmt>
      <PrintingPublicationsPostageAmt>515</PrintingPublicationsPostageAmt>
      <OtherExpensesTotalAmt>17018</OtherExpensesTotalAmt>
      <TotalExpensesAmt>42927</TotalExpensesAmt>
      <ExcessOrDeficitForYearAmt>42202</ExcessOrDeficitForYearAmt>
      <NetAssetsOrFundBalancesBOYAmt>194216</NetAssetsOrFundBalancesBOYAmt>
      <NetAssetsOrFundBalancesEOYAmt>236418</NetAssetsOrFundBalancesEOYAmt>
      <InfoInScheduleOPartIIInd>X</InfoInScheduleOPartIIInd>
      <CashSavingsAndInvestmentsGrp>
        <BOYAmt>195154</BOYAmt>
        <EOYAmt>237077</EOYAmt>
      </CashSavingsAndInvestmentsGrp>
      <LandAndBuildingsGrp>
        <BOYAmt>0</BOYAmt>
        <EOYAmt>0</EOYAmt>
      </LandAndBuildingsGrp>
      <OtherAssetsTotalDetail>
        <BOYAmt>0</BOYAmt>
        <EOYAmt>0</EOYAmt>
      </OtherAssetsTotalDetail>
      <Form990TotalAssetsGrp>
        <BOYAmt>195154</BOYAmt>
        <EOYAmt>237077</EOYAmt>
      </Form990TotalAssetsGrp>
      <SumOfTotalLiabilitiesGrp>
        <BOYAmt>938</BOYAmt>
        <EOYAmt>659</EOYAmt>
      </SumOfTotalLiabilitiesGrp>
      <NetAssetsOrFundBalancesGrp>
        <BOYAmt>194216</BOYAmt>
        <EOYAmt>236418</EOYAmt>
      </NetAssetsOrFundBalancesGrp>
      <PrimaryExemptPurposeTxt>To overcome the challenges of C.S.</PrimaryExemptPurposeTxt>
      <ProgramSrvcAccomplishmentGrp>
        <DescriptionProgramSrvcAccomTxt>Updated &amp; printed new trifold information about Costello Syndrome for families</DescriptionProgramSrvcAccomTxt>
        <ProgramServiceExpensesAmt>0</ProgramServiceExpensesAmt>
      </ProgramSrvcAccomplishmentGrp>
      <ProgramSrvcAccomplishmentGrp>
        <DescriptionProgramSrvcAccomTxt>Advocacy for families affected by Costello syndrome</DescriptionProgramSrvcAccomTxt>
        <ProgramServiceExpensesAmt>0</ProgramServiceExpensesAmt>
      </ProgramSrvcAccomplishmentGrp>
      <ProgramSrvcAccomplishmentGrp>
        <DescriptionProgramSrvcAccomTxt>Reviewed and updated CSFN Strategic Plan for 2024-2025</DescriptionProgramSrvcAccomTxt>
        <ProgramServiceExpensesAmt>0</ProgramServiceExpensesAmt>
      </ProgramSrvcAccomplishmentGrp>
      <TotalProgramServiceExpensesAmt>0</TotalProgramServiceExpensesAmt>
      <OfficerDirectorTrusteeEmplGrp>
        <PersonNm>Heather Hamblin</PersonNm>
        <TitleTxt>President</TitleTxt>
        <AverageHrsPerWkDevotedToPosRt>3.00</AverageHrsPerWkDevotedToPosRt>
        <CompensationAmt>0</CompensationAmt>
        <EmployeeBenefitProgramAmt>0</EmployeeBenefitProgramAmt>
        <ExpenseAccountOtherAllwncAmt>0</ExpenseAccountOtherAllwncAmt>
      </OfficerDirectorTrusteeEmplGrp>
      <OfficerDirectorTrusteeEmplGrp>
        <PersonNm>Mary Ernst</PersonNm>
        <TitleTxt>Vice President</TitleTxt>
        <AverageHrsPerWkDevotedToPosRt>1.50</AverageHrsPerWkDevotedToPosRt>
        <CompensationAmt>0</CompensationAmt>
        <EmployeeBenefitProgramAmt>0</EmployeeBenefitProgramAmt>
        <ExpenseAccountOtherAllwncAmt>0</ExpenseAccountOtherAllwncAmt>
      </OfficerDirectorTrusteeEmplGrp>
      <OfficerDirectorTrusteeEmplGrp>
        <PersonNm>Ellyn Farrelly</PersonNm>
        <TitleTxt>Secretary</TitleTxt>
        <AverageHrsPerWkDevotedToPosRt>1.50</AverageHrsPerWkDevotedToPosRt>
        <CompensationAmt>0</CompensationAmt>
        <EmployeeBenefitProgramAmt>0</EmployeeBenefitProgramAmt>
        <ExpenseAccountOtherAllwncAmt>0</ExpenseAccountOtherAllwncAmt>
      </OfficerDirectorTrusteeEmplGrp>
      <OfficerDirectorTrusteeEmplGrp>
        <PersonNm>Robert Hefner</PersonNm>
        <TitleTxt>Treasurer</TitleTxt>
        <AverageHrsPerWkDevotedToPosRt>1.00</AverageHrsPerWkDevotedToPosRt>
        <CompensationAmt>0</CompensationAmt>
        <EmployeeBenefitProgramAmt>0</EmployeeBenefitProgramAmt>
        <ExpenseAccountOtherAllwncAmt>0</ExpenseAccountOtherAllwncAmt>
      </OfficerDirectorTrusteeEmplGrp>
      <OfficerDirectorTrusteeEmplGrp>
        <PersonNm>Lara Weeks</PersonNm>
        <TitleTxt>Board Member</TitleTxt>
        <AverageHrsPerWkDevotedToPosRt>1.00</AverageHrsPerWkDevotedToPosRt>
        <CompensationAmt>0</CompensationAmt>
        <EmployeeBenefitProgramAmt>0</EmployeeBenefitProgramAmt>
        <ExpenseAccountOtherAllwncAmt>0</ExpenseAccountOtherAllwncAmt>
      </OfficerDirectorTrusteeEmplGrp>
      <OfficerDirectorTrusteeEmplGrp>
        <PersonNm>Jill Kazakoff</PersonNm>
        <TitleTxt>Board Member</TitleTxt>
        <AverageHrsPerWkDevotedToPosRt>1.00</AverageHrsPerWkDevotedToPosRt>
        <CompensationAmt>0</CompensationAmt>
        <EmployeeBenefitProgramAmt>0</EmployeeBenefitProgramAmt>
        <ExpenseAccountOtherAllwncAmt>0</ExpenseAccountOtherAllwncAmt>
      </OfficerDirectorTrusteeEmplGrp>
      <OfficerDirectorTrusteeEmplGrp>
        <PersonNm referenceDocumentId="STMA07">Christin Griffis</PersonNm>
        <TitleTxt>Board Member</TitleTxt>
        <AverageHrsPerWkDevotedToPosRt>1.00</AverageHrsPerWkDevotedToPosRt>
        <CompensationAmt>0</CompensationAmt>
        <EmployeeBenefitProgramAmt>0</EmployeeBenefitProgramAmt>
        <ExpenseAccountOtherAllwncAmt>0</ExpenseAccountOtherAllwncAmt>
      </OfficerDirectorTrusteeEmplGrp>
      <OfficerDirectorTrusteeEmplGrp>
        <PersonNm>Sheri Holcomb</PersonNm>
        <TitleTxt>Board Member</TitleTxt>
        <AverageHrsPerWkDevotedToPosRt>1.00</AverageHrsPerWkDevotedToPosRt>
        <CompensationAmt>0</CompensationAmt>
        <EmployeeBenefitProgramAmt>0</EmployeeBenefitProgramAmt>
        <ExpenseAccountOtherAllwncAmt>0</ExpenseAccountOtherAllwncAmt>
      </OfficerDirectorTrusteeEmplGrp>
      <OfficerDirectorTrusteeEmplGrp>
        <PersonNm>Gail Deckman</PersonNm>
        <TitleTxt>Board Member</TitleTxt>
        <AverageHrsPerWkDevotedToPosRt>1.00</AverageHrsPerWkDevotedToPosRt>
        <CompensationAmt>0</CompensationAmt>
        <EmployeeBenefitProgramAmt>0</EmployeeBenefitProgramAmt>
        <ExpenseAccountOtherAllwncAmt>0</ExpenseAccountOtherAllwncAmt>
      </OfficerDirectorTrusteeEmplGrp>
      <OfficerDirectorTrusteeEmplGrp>
        <PersonNm>Sandra Taylor</PersonNm>
        <TitleTxt>Executive Director</TitleTxt>
        <AverageHrsPerWkDevotedToPosRt>12.00</AverageHrsPerWkDevotedToPosRt>
        <CompensationAmt>0</CompensationAmt>
        <EmployeeBenefitProgramAmt>0</EmployeeBenefitProgramAmt>
        <ExpenseAccountOtherAllwncAmt>0</ExpenseAccountOtherAllwncAmt>
      </OfficerDirectorTrusteeEmplGrp>
      <ActivitiesNotPreviouslyRptInd>false</ActivitiesNotPreviouslyRptInd>
      <ChgMadeToOrgnzngDocNotRptInd>false</ChgMadeToOrgnzngDocNotRptInd>
      <OrganizationHadUBIInd>false</OrganizationHadUBIInd>
      <SubjectToProxyTaxInd>false</SubjectToProxyTaxInd>
      <OrganizationDissolvedEtcInd>false</OrganizationDissolvedEtcInd>
      <Form1120PolFiledInd>false</Form1120PolFiledInd>
      <MadeLoansToFromOfficersInd>false</MadeLoansToFromOfficersInd>
      <EngagedInExcessBenefitTransInd>false</EngagedInExcessBenefitTransInd>
      <ProhibitedTaxShelterTransInd>false</ProhibitedTaxShelterTransInd>
      <BooksInCareOfDetail>
        <PersonNm>Roberta Lawrence</PersonNm>
        <USAddress>
          <AddressLine1Txt>7520 Nautical Ct</AddressLine1Txt>
          <CityNm>Panama City</CityNm>
          <StateAbbreviationCd>FL</StateAbbreviationCd>
          <ZIPCd>32409</ZIPCd>
        </USAddress>
        <PhoneNum>8502301399</PhoneNum>
      </BooksInCareOfDetail>
      <ForeignFinancialAccountInd>false</ForeignFinancialAccountInd>
      <ForeignOfficeInd>false</ForeignOfficeInd>
      <DonorAdvisedFndsInd>false</DonorAdvisedFndsInd>
      <OperateHospitalInd>false</OperateHospitalInd>
      <TanningServicesProvidedInd>false</TanningServicesProvidedInd>
      <RelatedOrganizationCtrlEntInd>false</RelatedOrganizationCtrlEntInd>
      <TransactionWithControlEntInd>false</TransactionWithControlEntInd>
      <PoliticalCampaignActyInd>false</PoliticalCampaignActyInd>
      <LobbyingActivitiesInd>false</LobbyingActivitiesInd>
      <SchoolOperatingInd>false</SchoolOperatingInd>
      <TrnsfrExmptNonChrtblRltdOrgInd>false</TrnsfrExmptNonChrtblRltdOrgInd>
      <PartVIOfCompOfHghstPdEmplTxt>NONE</PartVIOfCompOfHghstPdEmplTxt>
      <PartVIHghstPdCntrctProfSrvcTxt>NONE</PartVIHghstPdCntrctProfSrvcTxt>
      <FiledScheduleAInd>true</FiledScheduleAInd>
    </IRS990EZ>
    <IRS990ScheduleA documentId="990A">
      <PubliclySupportedOrg509a2Ind>X</PubliclySupportedOrg509a2Ind>
      <GiftsGrantsContrisRcvd509Grp>
        <CurrentTaxYearMinus4YearsAmt>56320</CurrentTaxYearMinus4YearsAmt>
        <CurrentTaxYearMinus3YearsAmt>64731</CurrentTaxYearMinus3YearsAmt>
        <CurrentTaxYearMinus2YearsAmt>50502</CurrentTaxYearMinus2YearsAmt>
        <CurrentTaxYearMinus1YearAmt>85778</CurrentTaxYearMinus1YearAmt>
        <CurrentTaxYearAmt>83824</CurrentTaxYearAmt>
        <TotalAmt>341155</TotalAmt>
      </GiftsGrantsContrisRcvd509Grp>
      <GrossReceiptsNonUnrltBusGrp>
        <CurrentTaxYearMinus1YearAmt>23156</CurrentTaxYearMinus1YearAmt>
        <TotalAmt>23156</TotalAmt>
      </GrossReceiptsNonUnrltBusGrp>
      <Total509Grp>
        <CurrentTaxYearMinus4YearsAmt>56320</CurrentTaxYearMinus4YearsAmt>
        <CurrentTaxYearMinus3YearsAmt>64731</CurrentTaxYearMinus3YearsAmt>
        <CurrentTaxYearMinus2YearsAmt>50502</CurrentTaxYearMinus2YearsAmt>
        <CurrentTaxYearMinus1YearAmt>108934</CurrentTaxYearMinus1YearAmt>
        <CurrentTaxYearAmt>83824</CurrentTaxYearAmt>
        <TotalAmt>364311</TotalAmt>
      </Total509Grp>
      <SubstAndDsqlfyPrsnsTotGrp>
        <CurrentTaxYearMinus4YearsAmt>0</CurrentTaxYearMinus4YearsAmt>
        <CurrentTaxYearMinus3YearsAmt>0</CurrentTaxYearMinus3YearsAmt>
        <CurrentTaxYearMinus2YearsAmt>0</CurrentTaxYearMinus2YearsAmt>
        <CurrentTaxYearMinus1YearAmt>0</CurrentTaxYearMinus1YearAmt>
        <CurrentTaxYearAmt>0</CurrentTaxYearAmt>
        <TotalAmt>0</TotalAmt>
      </SubstAndDsqlfyPrsnsTotGrp>
      <PublicSupportTotal509Amt>364311</PublicSupportTotal509Amt>
      <GrossInvestmentIncome509Grp>
        <CurrentTaxYearMinus4YearsAmt>1305</CurrentTaxYearMinus4YearsAmt>
        <CurrentTaxYearMinus3YearsAmt>763</CurrentTaxYearMinus3YearsAmt>
        <CurrentTaxYearMinus1YearAmt>4</CurrentTaxYearMinus1YearAmt>
        <CurrentTaxYearAmt>15</CurrentTaxYearAmt>
        <TotalAmt>2087</TotalAmt>
      </GrossInvestmentIncome509Grp>
      <InvestmentIncomeAndUBTIGrp>
        <CurrentTaxYearMinus4YearsAmt>1305</CurrentTaxYearMinus4YearsAmt>
        <CurrentTaxYearMinus3YearsAmt>763</CurrentTaxYearMinus3YearsAmt>
        <CurrentTaxYearMinus1YearAmt>4</CurrentTaxYearMinus1YearAmt>
        <CurrentTaxYearAmt>15</CurrentTaxYearAmt>
        <TotalAmt>2087</TotalAmt>
      </InvestmentIncomeAndUBTIGrp>
      <TotalSupportCalendarYearGrp>
        <CurrentTaxYearMinus4YearsAmt>57625</CurrentTaxYearMinus4YearsAmt>
        <CurrentTaxYearMinus3YearsAmt>65494</CurrentTaxYearMinus3YearsAmt>
        <CurrentTaxYearMinus2YearsAmt>50502</CurrentTaxYearMinus2YearsAmt>
        <CurrentTaxYearMinus1YearAmt>108938</CurrentTaxYearMinus1YearAmt>
        <CurrentTaxYearAmt>83839</CurrentTaxYearAmt>
        <TotalAmt>366398</TotalAmt>
      </TotalSupportCalendarYearGrp>
      <PublicSupportCY509Pct>0.99430</PublicSupportCY509Pct>
      <PublicSupportPY509Pct>0.99130</PublicSupportPY509Pct>
      <InvestmentIncomeCYPct>0.01000</InvestmentIncomeCYPct>
      <InvestmentIncomePYPct>0.01000</InvestmentIncomePYPct>
      <ThirtyThrPctSuprtTestsCY509Ind>X</ThirtyThrPctSuprtTestsCY509Ind>
    </IRS990ScheduleA>
    <IRS990ScheduleO documentId="990O">
      <SupplementalInformationDetail>
        <FormAndLineReferenceDesc>Description of other expenses Part I line 16</FormAndLineReferenceDesc>
        <ExplanationTxt>Description AmountResearch Expense 6,5002024 Conf Child Care Expense 4,574F2F meeting Expense 5,944</ExplanationTxt>
      </SupplementalInformationDetail>
      <SupplementalInformationDetail>
        <FormAndLineReferenceDesc>Description of total liabilities Part II line 26</FormAndLineReferenceDesc>
        <ExplanationTxt>Category Beginning of Year End of YearFederal Payroll taxes payable 938 659</ExplanationTxt>
      </SupplementalInformationDetail>
    </IRS990ScheduleO>
    <CompensationExplanation documentId="STMA07">
      <CompensationExplanationGrp>
        <PersonNm>Christin Griffis</PersonNm>
        <ShortExplanationTxt>Sandra is the Executive Director</ShortExplanationTxt>
      </CompensationExplanationGrp>
    </CompensationExplanation>
  </ReturnData>
</Return>