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  <xsd:element id="gmtx_TwoThousandSeventeenPlanMember" name="TwoThousandSeventeenPlanMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="gmtx_TwoThousandTwentyOneEmployeeStockPurchasePlanMember" name="TwoThousandTwentyOneEmployeeStockPurchasePlanMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="gmtx_TwoThousandTwentyOneGeminiEquityIncentivePlanMember" name="TwoThousandTwentyOneGeminiEquityIncentivePlanMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="gmtx_TwoThousandTwentyOneStockOptionAndIncentivePlanMember" name="TwoThousandTwentyOneStockOptionAndIncentivePlanMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="gmtx_UnvestedRestrictedStockMember" name="UnvestedRestrictedStockMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="gmtx_WarrantsToPurchaseSeriesAPreferredStockMember" name="WarrantsToPurchaseSeriesAPreferredStockMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="gmtx_EmergingGrowthCompanyStatusPolicyTextBlock" name="EmergingGrowthCompanyStatusPolicyTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="gmtx_CommitmentsAndContingenciesDetailsTable" name="CommitmentsAndContingenciesDetailsTable" type="xbrli:stringItemType" substitutionGroup="xbrldt:hypercubeItem" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="gmtx_ConvertiblePromissoryNotesTable" name="ConvertiblePromissoryNotesTable" type="xbrli:stringItemType" substitutionGroup="xbrldt:hypercubeItem" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="gmtx_NatureOfBusinessTable" name="NatureOfBusinessTable" type="xbrli:stringItemType" substitutionGroup="xbrldt:hypercubeItem" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="gmtx_RelatedPartyTransactionsDetailsTable" name="RelatedPartyTransactionsDetailsTable" type="xbrli:stringItemType" substitutionGroup="xbrldt:hypercubeItem" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="gmtx_DisclosureOfSummaryOfNetProceedsFromBusinessCombinationTableTextBlock" name="DisclosureOfSummaryOfNetProceedsFromBusinessCombinationTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="gmtx_DisclosureOfSummaryOfSharesIssuedFromBusinessCombinationTableTextBlock" name="DisclosureOfSummaryOfSharesIssuedFromBusinessCombinationTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="gmtx_PropertyAndEquipmentEstimatedUsefulLivesTableTextBlock" name="PropertyAndEquipmentEstimatedUsefulLivesTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="gmtx_ScheduleOfAccruedExpensesAndOtherCurrentLiabilitiesTableTextBlock" name="ScheduleOfAccruedExpensesAndOtherCurrentLiabilitiesTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
</xsd:schema>
