﻿<?xml version="1.0" encoding="utf-8"?>
<Return returnVersion="2024v5.0" xmlns="http://www.irs.gov/efile" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
  <ReturnHeader binaryAttachmentCnt="0">
    <ReturnTs>2026-01-07T15:24:19-07:00</ReturnTs>
    <TaxPeriodEndDt>2025-09-30</TaxPeriodEndDt>
    <ReturnTypeCd>990EZ</ReturnTypeCd>
    <TaxPeriodBeginDt>2024-10-01</TaxPeriodBeginDt>
    <Filer>
      <EIN>300585106</EIN>
      <BusinessName>
        <BusinessNameLine1Txt>ROTHMUND-THOMSON SYNDROME FOUNDATION</BusinessNameLine1Txt>
      </BusinessName>
      <BusinessNameControlTxt>ROTH</BusinessNameControlTxt>
      <PhoneNum>7038023167</PhoneNum>
      <USAddress>
        <AddressLine1Txt>4307 Woodward Court</AddressLine1Txt>
        <CityNm>Chantilly</CityNm>
        <StateAbbreviationCd>VA</StateAbbreviationCd>
        <ZIPCd>20151</ZIPCd>
      </USAddress>
    </Filer>
    <BusinessOfficerGrp>
      <PersonNm>Staci Hanson</PersonNm>
      <PersonTitleTxt>Chair</PersonTitleTxt>
      <PhoneNum>2073320361</PhoneNum>
      <SignatureDt>2026-01-07</SignatureDt>
    </BusinessOfficerGrp>
    <IRSResponsiblePrtyInfoCurrInd>1</IRSResponsiblePrtyInfoCurrInd>
    <TaxYr>2024</TaxYr>
    <BuildTS>2025-03-06 01:10:19Z</BuildTS>
  </ReturnHeader>
  <ReturnData documentCnt="4">
    <IRS990EZ documentId="R000001" referenceDocumentId="R000004" softwareId="24021167" softwareVersionNum="v1.00">
      <MethodOfAccountingCashInd>X</MethodOfAccountingCashInd>
      <WebsiteAddressTxt>www.rtsplace.org</WebsiteAddressTxt>
      <Organization501c3Ind referenceDocumentId="R000002">X</Organization501c3Ind>
      <TypeOfOrganizationCorpInd>X</TypeOfOrganizationCorpInd>
      <GrossReceiptsAmt>61869</GrossReceiptsAmt>
      <InfoInScheduleOPartIInd>X</InfoInScheduleOPartIInd>
      <ContributionsGiftsGrantsEtcAmt>49079</ContributionsGiftsGrantsEtcAmt>
      <ProgramServiceRevenueAmt>0</ProgramServiceRevenueAmt>
      <MembershipDuesAmt>0</MembershipDuesAmt>
      <InvestmentIncomeAmt>0</InvestmentIncomeAmt>
      <SaleOfAssetsGrossAmt>0</SaleOfAssetsGrossAmt>
      <CostOrOtherBasisExpenseSaleAmt>0</CostOrOtherBasisExpenseSaleAmt>
      <GainOrLossFromSaleOfAssetsAmt>0</GainOrLossFromSaleOfAssetsAmt>
      <GamingGrossIncomeAmt>12000</GamingGrossIncomeAmt>
      <FundraisingGrossIncomeAmt fndrsngEventContriPrevRptAmt="0">790</FundraisingGrossIncomeAmt>
      <SpecialEventsDirectExpensesAmt>5970</SpecialEventsDirectExpensesAmt>
      <SpecialEventsNetIncomeLossAmt>6820</SpecialEventsNetIncomeLossAmt>
      <GrossSalesOfInventoryAmt>0</GrossSalesOfInventoryAmt>
      <CostOfGoodsSoldAmt>0</CostOfGoodsSoldAmt>
      <GrossProfitLossSlsOfInvntryAmt>0</GrossProfitLossSlsOfInvntryAmt>
      <OtherRevenueTotalAmt>0</OtherRevenueTotalAmt>
      <TotalRevenueAmt>55899</TotalRevenueAmt>
      <GrantsAndSimilarAmountsPaidAmt>32977</GrantsAndSimilarAmountsPaidAmt>
      <BenefitsPaidToOrForMembersAmt>0</BenefitsPaidToOrForMembersAmt>
      <SalariesOtherCompEmplBnftAmt>0</SalariesOtherCompEmplBnftAmt>
      <FeesAndOtherPymtToIndCntrctAmt>0</FeesAndOtherPymtToIndCntrctAmt>
      <OccupancyRentUtltsAndMaintAmt>0</OccupancyRentUtltsAndMaintAmt>
      <PrintingPublicationsPostageAmt>291</PrintingPublicationsPostageAmt>
      <OtherExpensesTotalAmt>2292</OtherExpensesTotalAmt>
      <TotalExpensesAmt>35560</TotalExpensesAmt>
      <ExcessOrDeficitForYearAmt>20339</ExcessOrDeficitForYearAmt>
      <NetAssetsOrFundBalancesBOYAmt>54636</NetAssetsOrFundBalancesBOYAmt>
      <OtherChangesInNetAssetsAmt>0</OtherChangesInNetAssetsAmt>
      <NetAssetsOrFundBalancesEOYAmt>74975</NetAssetsOrFundBalancesEOYAmt>
      <CashSavingsAndInvestmentsGrp>
        <BOYAmt>54636</BOYAmt>
        <EOYAmt>74975</EOYAmt>
      </CashSavingsAndInvestmentsGrp>
      <LandAndBuildingsGrp>
        <BOYAmt>0</BOYAmt>
        <EOYAmt>0</EOYAmt>
      </LandAndBuildingsGrp>
      <OtherAssetsTotalDetail>
        <BOYAmt>0</BOYAmt>
        <EOYAmt>0</EOYAmt>
      </OtherAssetsTotalDetail>
      <Form990TotalAssetsGrp>
        <BOYAmt>54636</BOYAmt>
        <EOYAmt>74975</EOYAmt>
      </Form990TotalAssetsGrp>
      <SumOfTotalLiabilitiesGrp>
        <BOYAmt>0</BOYAmt>
        <EOYAmt>0</EOYAmt>
      </SumOfTotalLiabilitiesGrp>
      <NetAssetsOrFundBalancesGrp>
        <BOYAmt>54636</BOYAmt>
        <EOYAmt>74975</EOYAmt>
      </NetAssetsOrFundBalancesGrp>
      <PrimaryExemptPurposeTxt>Foster worldwide awareness and education about RTS and related disorders and to encourage research through support of scientists and physicians devoted to studying the clinical spectrum, molecular and cellular basis of RECQL4 and related syndromes</PrimaryExemptPurposeTxt>
      <ProgramSrvcAccomplishmentGrp>
        <DescriptionProgramSrvcAccomTxt>Provided a funding to Baylor College of Medicine to sponsor continued research on RTS and to fund RTS clinical studies and transfer of patient registry to Genial.</DescriptionProgramSrvcAccomTxt>
        <GrantsAndAllocationsAmt>0</GrantsAndAllocationsAmt>
        <ProgramServiceExpensesAmt>30000</ProgramServiceExpensesAmt>
      </ProgramSrvcAccomplishmentGrp>
      <ProgramSrvcAccomplishmentGrp>
        <DescriptionProgramSrvcAccomTxt>Sponsor a sharing and caring conference for RTS families and medical professionals.</DescriptionProgramSrvcAccomTxt>
        <GrantsAndAllocationsAmt>0</GrantsAndAllocationsAmt>
        <ProgramServiceExpensesAmt>1477</ProgramServiceExpensesAmt>
      </ProgramSrvcAccomplishmentGrp>
      <ProgramSrvcAccomplishmentGrp>
        <DescriptionProgramSrvcAccomTxt>Paid for a RTS video to be used for education and potential fundraising in the future.</DescriptionProgramSrvcAccomTxt>
        <GrantsAndAllocationsAmt>0</GrantsAndAllocationsAmt>
        <ProgramServiceExpensesAmt>1500</ProgramServiceExpensesAmt>
      </ProgramSrvcAccomplishmentGrp>
      <TotalProgramServiceExpensesAmt>32977</TotalProgramServiceExpensesAmt>
      <OfficerDirectorTrusteeEmplGrp>
        <PersonNm>Staci Hanson</PersonNm>
        <TitleTxt>Chair</TitleTxt>
        <AverageHrsPerWkDevotedToPosRt>10</AverageHrsPerWkDevotedToPosRt>
        <CompensationAmt>0</CompensationAmt>
        <EmployeeBenefitProgramAmt>0</EmployeeBenefitProgramAmt>
        <ExpenseAccountOtherAllwncAmt>0</ExpenseAccountOtherAllwncAmt>
      </OfficerDirectorTrusteeEmplGrp>
      <OfficerDirectorTrusteeEmplGrp>
        <PersonNm>Kara Hanson</PersonNm>
        <TitleTxt>Treasurer</TitleTxt>
        <AverageHrsPerWkDevotedToPosRt>5</AverageHrsPerWkDevotedToPosRt>
        <CompensationAmt>0</CompensationAmt>
        <EmployeeBenefitProgramAmt>0</EmployeeBenefitProgramAmt>
        <ExpenseAccountOtherAllwncAmt>0</ExpenseAccountOtherAllwncAmt>
      </OfficerDirectorTrusteeEmplGrp>
      <OfficerDirectorTrusteeEmplGrp>
        <PersonNm>Bekkah Blankers</PersonNm>
        <TitleTxt>Vice Chair</TitleTxt>
        <AverageHrsPerWkDevotedToPosRt>10</AverageHrsPerWkDevotedToPosRt>
        <CompensationAmt>0</CompensationAmt>
        <EmployeeBenefitProgramAmt>0</EmployeeBenefitProgramAmt>
        <ExpenseAccountOtherAllwncAmt>0</ExpenseAccountOtherAllwncAmt>
      </OfficerDirectorTrusteeEmplGrp>
      <OfficerDirectorTrusteeEmplGrp>
        <PersonNm>Tamara Madsen</PersonNm>
        <TitleTxt>Director</TitleTxt>
        <AverageHrsPerWkDevotedToPosRt>5</AverageHrsPerWkDevotedToPosRt>
        <CompensationAmt>0</CompensationAmt>
        <EmployeeBenefitProgramAmt>0</EmployeeBenefitProgramAmt>
        <ExpenseAccountOtherAllwncAmt>0</ExpenseAccountOtherAllwncAmt>
      </OfficerDirectorTrusteeEmplGrp>
      <OfficerDirectorTrusteeEmplGrp>
        <PersonNm>Camille Carlson</PersonNm>
        <TitleTxt>Secretary</TitleTxt>
        <AverageHrsPerWkDevotedToPosRt>5</AverageHrsPerWkDevotedToPosRt>
        <CompensationAmt>0</CompensationAmt>
        <EmployeeBenefitProgramAmt>0</EmployeeBenefitProgramAmt>
        <ExpenseAccountOtherAllwncAmt>0</ExpenseAccountOtherAllwncAmt>
      </OfficerDirectorTrusteeEmplGrp>
      <OfficerDirectorTrusteeEmplGrp>
        <PersonNm>Lisette Riggle</PersonNm>
        <TitleTxt>Director</TitleTxt>
        <AverageHrsPerWkDevotedToPosRt>5</AverageHrsPerWkDevotedToPosRt>
        <CompensationAmt>0</CompensationAmt>
        <EmployeeBenefitProgramAmt>0</EmployeeBenefitProgramAmt>
        <ExpenseAccountOtherAllwncAmt>0</ExpenseAccountOtherAllwncAmt>
      </OfficerDirectorTrusteeEmplGrp>
      <ActivitiesNotPreviouslyRptInd>0</ActivitiesNotPreviouslyRptInd>
      <ChgMadeToOrgnzngDocNotRptInd>0</ChgMadeToOrgnzngDocNotRptInd>
      <OrganizationHadUBIInd>0</OrganizationHadUBIInd>
      <SubjectToProxyTaxInd>0</SubjectToProxyTaxInd>
      <OrganizationDissolvedEtcInd>0</OrganizationDissolvedEtcInd>
      <DirectIndirectPltclExpendAmt>0</DirectIndirectPltclExpendAmt>
      <Form1120PolFiledInd>0</Form1120PolFiledInd>
      <MadeLoansToFromOfficersInd>0</MadeLoansToFromOfficersInd>
      <TaxImposedUnderIRC4911Amt>0</TaxImposedUnderIRC4911Amt>
      <TaxImposedUnderIRC4912Amt>0</TaxImposedUnderIRC4912Amt>
      <TaxImposedUnderIRC4955Amt>0</TaxImposedUnderIRC4955Amt>
      <EngagedInExcessBenefitTransInd>0</EngagedInExcessBenefitTransInd>
      <TaxImposedOnOrganizationMgrAmt>0</TaxImposedOnOrganizationMgrAmt>
      <TaxReimbursedByOrganizationAmt>0</TaxReimbursedByOrganizationAmt>
      <ProhibitedTaxShelterTransInd>0</ProhibitedTaxShelterTransInd>
      <StatesWhereCopyOfReturnIsFldCd>CA</StatesWhereCopyOfReturnIsFldCd>
      <StatesWhereCopyOfReturnIsFldCd>FL</StatesWhereCopyOfReturnIsFldCd>
      <StatesWhereCopyOfReturnIsFldCd>IL</StatesWhereCopyOfReturnIsFldCd>
      <StatesWhereCopyOfReturnIsFldCd>MA</StatesWhereCopyOfReturnIsFldCd>
      <StatesWhereCopyOfReturnIsFldCd>MD</StatesWhereCopyOfReturnIsFldCd>
      <StatesWhereCopyOfReturnIsFldCd>ME</StatesWhereCopyOfReturnIsFldCd>
      <StatesWhereCopyOfReturnIsFldCd>MI</StatesWhereCopyOfReturnIsFldCd>
      <StatesWhereCopyOfReturnIsFldCd>NH</StatesWhereCopyOfReturnIsFldCd>
      <StatesWhereCopyOfReturnIsFldCd>NM</StatesWhereCopyOfReturnIsFldCd>
      <StatesWhereCopyOfReturnIsFldCd>NY</StatesWhereCopyOfReturnIsFldCd>
      <StatesWhereCopyOfReturnIsFldCd>OK</StatesWhereCopyOfReturnIsFldCd>
      <StatesWhereCopyOfReturnIsFldCd>PA</StatesWhereCopyOfReturnIsFldCd>
      <StatesWhereCopyOfReturnIsFldCd>UT</StatesWhereCopyOfReturnIsFldCd>
      <StatesWhereCopyOfReturnIsFldCd>VA</StatesWhereCopyOfReturnIsFldCd>
      <StatesWhereCopyOfReturnIsFldCd>WA</StatesWhereCopyOfReturnIsFldCd>
      <BooksInCareOfDetail>
        <PersonNm>Kara Hanson</PersonNm>
        <USAddress>
          <AddressLine1Txt>4307 Woodward Court</AddressLine1Txt>
          <CityNm>Chantilly</CityNm>
          <StateAbbreviationCd>VA</StateAbbreviationCd>
          <ZIPCd>20151</ZIPCd>
        </USAddress>
        <PhoneNum>7038023167</PhoneNum>
      </BooksInCareOfDetail>
      <ForeignFinancialAccountInd>0</ForeignFinancialAccountInd>
      <ForeignOfficeInd>0</ForeignOfficeInd>
      <DonorAdvisedFndsInd>0</DonorAdvisedFndsInd>
      <OperateHospitalInd>0</OperateHospitalInd>
      <TanningServicesProvidedInd>0</TanningServicesProvidedInd>
      <RelatedOrganizationCtrlEntInd>0</RelatedOrganizationCtrlEntInd>
      <TransactionWithControlEntInd>0</TransactionWithControlEntInd>
      <PoliticalCampaignActyInd>0</PoliticalCampaignActyInd>
      <LobbyingActivitiesInd>0</LobbyingActivitiesInd>
      <SchoolOperatingInd>0</SchoolOperatingInd>
      <TrnsfrExmptNonChrtblRltdOrgInd>0</TrnsfrExmptNonChrtblRltdOrgInd>
      <PartVIOfCompOfHghstPdEmplTxt>NONE</PartVIOfCompOfHghstPdEmplTxt>
      <PartVIHghstPdCntrctProfSrvcTxt>NONE</PartVIHghstPdCntrctProfSrvcTxt>
      <FiledScheduleAInd>1</FiledScheduleAInd>
    </IRS990EZ>
    <IRS990ScheduleA documentId="R000002" softwareId="24021167" softwareVersionNum="v1.00">
      <PublicOrganization170Ind>X</PublicOrganization170Ind>
      <GiftsGrantsContriRcvd170Grp>
        <CurrentTaxYearMinus4YearsAmt>61557</CurrentTaxYearMinus4YearsAmt>
        <CurrentTaxYearMinus3YearsAmt>55568</CurrentTaxYearMinus3YearsAmt>
        <CurrentTaxYearMinus2YearsAmt>31322</CurrentTaxYearMinus2YearsAmt>
        <CurrentTaxYearMinus1YearAmt>31335</CurrentTaxYearMinus1YearAmt>
        <CurrentTaxYearAmt>49079</CurrentTaxYearAmt>
        <TotalAmt>228861</TotalAmt>
      </GiftsGrantsContriRcvd170Grp>
      <TotalCalendarYear170Grp>
        <CurrentTaxYearMinus4YearsAmt>61557</CurrentTaxYearMinus4YearsAmt>
        <CurrentTaxYearMinus3YearsAmt>55568</CurrentTaxYearMinus3YearsAmt>
        <CurrentTaxYearMinus2YearsAmt>31322</CurrentTaxYearMinus2YearsAmt>
        <CurrentTaxYearMinus1YearAmt>31335</CurrentTaxYearMinus1YearAmt>
        <CurrentTaxYearAmt>49079</CurrentTaxYearAmt>
        <TotalAmt>228861</TotalAmt>
      </TotalCalendarYear170Grp>
      <PublicSupportTotal170Amt>228861</PublicSupportTotal170Amt>
      <OtherIncome170Grp>
        <CurrentTaxYearMinus4YearsAmt>160</CurrentTaxYearMinus4YearsAmt>
        <CurrentTaxYearMinus3YearsAmt>1665</CurrentTaxYearMinus3YearsAmt>
        <CurrentTaxYearMinus2YearsAmt>75</CurrentTaxYearMinus2YearsAmt>
        <CurrentTaxYearMinus1YearAmt>80</CurrentTaxYearMinus1YearAmt>
        <CurrentTaxYearAmt>0</CurrentTaxYearAmt>
        <TotalAmt>1980</TotalAmt>
      </OtherIncome170Grp>
      <TotalSupportAmt>230841</TotalSupportAmt>
      <PublicSupportCY170Pct>0.99142</PublicSupportCY170Pct>
      <PublicSupportPY170Pct>0.99130</PublicSupportPY170Pct>
      <ThirtyThrPctSuprtTestsCY170Ind>X</ThirtyThrPctSuprtTestsCY170Ind>
      <Form990ScheduleAPartVIGrp>
        <FormAndLineReferenceDesc>Schedule A, Part II, Line 10</FormAndLineReferenceDesc>
        <ExplanationTxt>We had no other income this year.</ExplanationTxt>
      </Form990ScheduleAPartVIGrp>
    </IRS990ScheduleA>
    <IRS990ScheduleB documentId="R000003" softwareId="24021167" softwareVersionNum="v1.00">
      <ContributorInformationGrp>
        <ContributorNum>RESTRICTED</ContributorNum>
        <ContributorBusinessName>
          <BusinessNameLine1>RESTRICTED</BusinessNameLine1>
        </ContributorBusinessName>
        <ContributorUSAddress>
          <AddressLine1>RESTRICTED</AddressLine1>
          <AddressLine2>RESTRICTED</AddressLine2>
          <City>RESTRICTED</City>
          <State>RESTRICTED</State>
          <ZIPCode>RESTRICTED</ZIPCode>
        </ContributorUSAddress>
        <TotalContributionsAmt>RESTRICTED</TotalContributionsAmt>
      </ContributorInformationGrp>
    </IRS990ScheduleB>
    <IRS990ScheduleO documentId="R000004" softwareId="24021167" softwareVersionNum="v1.00">
      <SupplementalInformationDetail>
        <FormAndLineReferenceDesc>Form 990-EZ, Part I, Line 16</FormAndLineReferenceDesc>
        <ExplanationTxt>Operating expenses and renewal fees for soliciting in numerous States.</ExplanationTxt>
      </SupplementalInformationDetail>
    </IRS990ScheduleO>
  </ReturnData>
</Return>