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  <xsd:element id="ptct_EmployeeDirectorAndConsultantStockOptionPlanMember" name="EmployeeDirectorAndConsultantStockOptionPlanMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="ptct_EmployeeStockPurchasePlanVotingPercentageLimitPercent" name="EmployeeStockPurchasePlanVotingPercentageLimitPercent" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ptct_Equity2009AndLongTermIncentivePlanAndStockIncentivePlan2013Member" name="Equity2009AndLongTermIncentivePlanAndStockIncentivePlan2013Member" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ptct_EquityAndLongTermIncentivePlan2009Member" name="EquityAndLongTermIncentivePlan2009Member" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="ptct_Feet" name="Feet" nillable="true" substitutionGroup="xbrli:item" type="xbrli:integerItemType" xbrli:periodType="instant" />
  <xsd:element abstract="true" id="ptct_FifthAnniversaryMember" name="FifthAnniversaryMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="ptct_FiniteLivedIntangibleAssetsAmortizationExpenseYearFiveAndThereafter" name="FiniteLivedIntangibleAssetsAmortizationExpenseYearFiveAndThereafter" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element abstract="true" id="ptct_GrantAndCollaborationMember" name="GrantAndCollaborationMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="ptct_InventoriesAndCostOfProductSalesPolicyTextBlock" name="InventoriesAndCostOfProductSalesPolicyTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element id="ptct_InvestmentInMRI" name="InvestmentInMRI" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element id="ptct_LesseeOperatingLeaseLiabilityPaymentsDueYearFiveandThereafter" name="LesseeOperatingLeaseLiabilityPaymentsDueYearFiveandThereafter" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element abstract="true" id="ptct_LiabilityDevelopmentandRegulatoryMilestoneMember" name="LiabilityDevelopmentandRegulatoryMilestoneMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ptct_LiabilityNetSalesMilestonesandRoyaltiesMember" name="LiabilityNetSalesMilestonesandRoyaltiesMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ptct_LicensingAndCollaborationAgreementMember" name="LicensingAndCollaborationAgreementMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="ptct_LineOfCreditFacilityAdditionalCapacityAvailable" name="LineOfCreditFacilityAdditionalCapacityAvailable" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element id="ptct_LoanAdvance" name="LoanAdvance" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element abstract="true" id="ptct_LongTermIncentivePlan2013Member" name="LongTermIncentivePlan2013Member" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ptct_MarathonPharmaceuticalsLLCMember" name="MarathonPharmaceuticalsLLCMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ptct_MidCapFinancialTrustMember" name="MidCapFinancialTrustMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ptct_MilestoneAxis" name="MilestoneAxis" nillable="true" substitutionGroup="xbrldt:dimensionItem" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ptct_MilestoneDomain" name="MilestoneDomain" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="ptct_MilestonePotentialAchievementsRegulatoryApproval" name="MilestonePotentialAchievementsRegulatoryApproval" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element id="ptct_MinimumPercentageOfDebtPrincipalAmountByInstrumentHolders" name="MinimumPercentageOfDebtPrincipalAmountByInstrumentHolders" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element id="ptct_NetDeferredTaxLiabilitiesConvertibleDebtInstruments" name="NetDeferredTaxLiabilitiesConvertibleDebtInstruments" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element id="ptct_NetProductSales" name="NetProductSales" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ptct_NewBuildingMember" name="NewBuildingMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="ptct_NumberOfCountries" name="NumberOfCountries" nillable="true" substitutionGroup="xbrli:item" type="xbrli:integerItemType" xbrli:periodType="duration" />
  <xsd:element id="ptct_NumberOfOperatingLeases" name="NumberOfOperatingLeases" nillable="true" substitutionGroup="xbrli:item" type="xbrli:integerItemType" xbrli:periodType="instant" />
  <xsd:element id="ptct_NumberOfProducts" name="NumberOfProducts" nillable="true" substitutionGroup="xbrli:item" type="xbrli:integerItemType" xbrli:periodType="instant" />
  <xsd:element id="ptct_NumberOfStatesInEuropeanEconomicArea" name="NumberOfStatesInEuropeanEconomicArea" nillable="true" substitutionGroup="xbrli:item" type="xbrli:integerItemType" xbrli:periodType="duration" />
  <xsd:element id="ptct_Numberofterms" name="Numberofterms" nillable="true" substitutionGroup="xbrli:item" type="xbrli:integerItemType" xbrli:periodType="instant" />
  <xsd:element id="ptct_PercentOfMarketRate" name="PercentOfMarketRate" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="instant" />
  <xsd:element abstract="true" id="ptct_PercentageofSalesforRoyaltiesMember" name="PercentageofSalesforRoyaltiesMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ptct_ProbabilityofSuccessMember" name="ProbabilityofSuccessMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="ptct_PublicOfferingsCosts" name="PublicOfferingsCosts" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ptct_ResearchAndDevelopmentEventMilestonesMember" name="ResearchAndDevelopmentEventMilestonesMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ptct_RestrictedStockAndRestrictedStockUnitsMember" name="RestrictedStockAndRestrictedStockUnitsMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="ptct_RevenueRecognitionMilestonePotentialAchievements" name="RevenueRecognitionMilestonePotentialAchievements" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element id="ptct_RocheAndSmaFoundationMember" name="RocheAndSmaFoundationMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ptct_RocheMember" name="RocheMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="ptct_SalesAllowanceAndOtherRelatedCosts" name="SalesAllowanceAndOtherRelatedCosts" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element abstract="true" id="ptct_SalesMilestonesMember" name="SalesMilestonesMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="ptct_SalesRebatesAndRoyaltiesCurrent" name="SalesRebatesAndRoyaltiesCurrent" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element id="ptct_ScheduleOfInterestExpenseRecognizedRelatedToConvertibleDebtTableTextBlock" name="ScheduleOfInterestExpenseRecognizedRelatedToConvertibleDebtTableTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element id="ptct_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorizedAnnualIncreaseAsPercentageOfStockOutstanding" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorizedAnnualIncreaseAsPercentageOfStockOutstanding" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element id="ptct_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorizedAnnualIncreaseNumber" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorizedAnnualIncreaseNumber" nillable="true" substitutionGroup="xbrli:item" type="xbrli:sharesItemType" xbrli:periodType="duration" />
  <xsd:element id="ptct_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorizedSharesSubjectToOutstandingAwards" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorizedSharesSubjectToOutstandingAwards" nillable="true" substitutionGroup="xbrli:item" type="xbrli:sharesItemType" xbrli:periodType="instant" />
  <xsd:element id="ptct_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsInducementGrantsForNonStatutoryStockOptions" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsInducementGrantsForNonStatutoryStockOptions" nillable="true" substitutionGroup="xbrli:item" type="xbrli:sharesItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ptct_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsIntrinsicValueRollForward" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsIntrinsicValueRollForward" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element id="ptct_StockAppreciationRightsLiabilityOutstanding" name="StockAppreciationRightsLiabilityOutstanding" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element abstract="true" id="ptct_StockIncentivePlan2013Member" name="StockIncentivePlan2013Member" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="ptct_Termforletterofcredit" name="Termforletterofcredit" nillable="true" substitutionGroup="xbrli:item" type="xbrli:durationItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ptct_TheCampusMember" name="TheCampusMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ptct_TranslarnaMember" name="TranslarnaMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="ptct_UpfrontLicensingFee" name="UpfrontLicensingFee" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ptct_WellcomeTrustLimitedMember" name="WellcomeTrustLimitedMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
</xsd:schema>
