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  <xsd:element name="ClearpointEquityInvestmentsFvNi" id="ptct_ClearpointEquityInvestmentsFvNi" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element name="ClearpointEquityInvestmentFvniUnrealizedGainLoss" id="ptct_ClearpointEquityInvestmentFvniUnrealizedGainLoss" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element name="EmflazaMember" id="ptct_EmflazaMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="TranslarnaMember" id="ptct_TranslarnaMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="ResearchAndDevelopmentAndSalesMilestonesMember" id="ptct_ResearchAndDevelopmentAndSalesMilestonesMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="PaymentOfRoyaltyObligation" id="ptct_PaymentOfRoyaltyObligation" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element name="WaylivraMember" id="ptct_WaylivraMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="TegsediMember" id="ptct_TegsediMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="ClearpointEquityInvestmentMember" id="ptct_ClearpointEquityInvestmentMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="DepositsAndOtherNoncurrentAssetsMember" id="ptct_DepositsAndOtherNoncurrentAssetsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="AtMarketOfferingSalesAgreementMember" id="ptct_AtMarketOfferingSalesAgreementMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="NumberOfProducts" id="ptct_NumberOfProducts" type="xbrli:integerItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="AmendedAndRestated2013LongTermIncentivePlanMember" id="ptct_AmendedAndRestated2013LongTermIncentivePlanMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="PotentialMilestonePaymentsDue" id="ptct_PotentialMilestonePaymentsDue" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="credit" />
  <xsd:element name="WarrenPremisesMember" id="ptct_WarrenPremisesMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="IncreaseDecreaseInContingentConsideration" id="ptct_IncreaseDecreaseInContingentConsideration" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="debit" />
  <xsd:element name="StockIssuedDuringPeriodSharesStockPurchaseAgreement" id="ptct_StockIssuedDuringPeriodSharesStockPurchaseAgreement" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" />
  <xsd:element name="StockIssuedDuringPeriodValueStockPurchaseAgreement" id="ptct_StockIssuedDuringPeriodValueStockPurchaseAgreement" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="credit" />
  <xsd:element name="UpstazaMember" id="ptct_UpstazaMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="FiniteLivedIntangibleAssetsAdditions" id="ptct_FiniteLivedIntangibleAssetsAdditions" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="debit" />
  <xsd:element name="IndefiniteLivedIntangibleAssetsAccumulatedDepreciationForeignCurrencyTranslationGainLoss" id="ptct_IndefiniteLivedIntangibleAssetsAccumulatedDepreciationForeignCurrencyTranslationGainLoss" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="debit" />
  <xsd:element name="FormerCensaSecurityholdersMember" id="ptct_FormerCensaSecurityholdersMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="CommonStockTradingArrangementMember" id="ptct_CommonStockTradingArrangementMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="RestrictedStockUnitsPerformanceBasedPsusMember" id="ptct_RestrictedStockUnitsPerformanceBasedPsusMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="AndRRoyaltyPurchaseAgreementMember" id="ptct_AndRRoyaltyPurchaseAgreementMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="AggregateRoyaltyPurchaseAgreementsMember" id="ptct_AggregateRoyaltyPurchaseAgreementsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardPerformancePeriod" id="ptct_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardPerformancePeriod" type="xbrli:durationItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" />
  <xsd:element name="MarketableSecuritiesUnrealizedGainLossForeignCurrencyTransaction" id="ptct_MarketableSecuritiesUnrealizedGainLossForeignCurrencyTransaction" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="credit" />
  <xsd:element name="EquityInvestmentsAndConvertibleDebtSecurities" id="ptct_EquityInvestmentsAndConvertibleDebtSecurities" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" xbrli:balance="debit" />
  <xsd:element name="MarketableEquityInvestmentsAndConvertibleDebtSecuritiesUnrealizedGainLoss" id="ptct_MarketableEquityInvestmentsAndConvertibleDebtSecuritiesUnrealizedGainLoss" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="credit" />
  <xsd:element name="MarketableEquityInvestmentsAndConvertibleDebtSecuritiesUnrealizedGainLossForeignCurrencyTransaction" id="ptct_MarketableEquityInvestmentsAndConvertibleDebtSecuritiesUnrealizedGainLossForeignCurrencyTransaction" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="credit" />
  <xsd:element name="MarketableEquityInvestmentsAndConvertibleDebtSecuritiesPurchases" id="ptct_MarketableEquityInvestmentsAndConvertibleDebtSecuritiesPurchases" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="credit" />
  <xsd:element name="ProceedsFromSaleAndRedemptionOfMarketableEquityInvestmentsAndConvertibleDebtSecurities" id="ptct_ProceedsFromSaleAndRedemptionOfMarketableEquityInvestmentsAndConvertibleDebtSecurities" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="debit" />
  <xsd:element name="EricPauwelsMember" id="ptct_EricPauwelsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="ChristineUtterMember" id="ptct_ChristineUtterMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="GainLossOnDispositionAndImpairmentOfTangibleAssets" id="ptct_GainLossOnDispositionAndImpairmentOfTangibleAssets" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="credit" />
  <xsd:element name="AggregateCashProceedsFromSaleOfFutureRoyalties" id="ptct_AggregateCashProceedsFromSaleOfFutureRoyalties" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="debit" />
  <xsd:element name="NoncashOrPartNoncashFixedAssetsTenantImprovementAllowance" id="ptct_NoncashOrPartNoncashFixedAssetsTenantImprovementAllowance" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="debit" />
  <xsd:element name="RestrictedStockUnitsPerformanceBasedPsusDevelopmentalRegulatoryOrCommercialGoalsMember" id="ptct_RestrictedStockUnitsPerformanceBasedPsusDevelopmentalRegulatoryOrCommercialGoalsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="RestrictedStockUnitsPerformanceBasedPsusStockPriceGoalsMember" id="ptct_RestrictedStockUnitsPerformanceBasedPsusStockPriceGoalsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="KebilidiMember" id="ptct_KebilidiMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="PtcAadcMember" id="ptct_PtcAadcMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="WarrenBuildingLeaseAmendmentMember" id="ptct_WarrenBuildingLeaseAmendmentMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="LifeScienceSegmentMember" id="ptct_LifeScienceSegmentMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="OccupancyCosts" id="ptct_OccupancyCosts" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="debit" />
  <xsd:element name="CostOfProductSalesExcludingAmortizationOfIntangibleAssetsAndRoyalties" id="ptct_CostOfProductSalesExcludingAmortizationOfIntangibleAssetsAndRoyalties" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="debit" />
  <xsd:element name="AdministrativeCosts" id="ptct_AdministrativeCosts" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="debit" />
  <xsd:element name="ProgramSpend" id="ptct_ProgramSpend" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="debit" />
  <xsd:element name="NovartisPharmaceuticalsCorporationMember" id="ptct_NovartisPharmaceuticalsCorporationMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="LicenseAndCollaborativeArrangementMember" id="ptct_LicenseAndCollaborativeArrangementMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="CashProceedsCollaborativeAgreementUpfrontPayment" id="ptct_CashProceedsCollaborativeAgreementUpfrontPayment" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="debit" />
  <xsd:element name="ContingentFutureProceedsBasedOnAchievementOfDevelopmentalRegulatoryAndSalesMilestonesAndTieredRoyalties" id="ptct_ContingentFutureProceedsBasedOnAchievementOfDevelopmentalRegulatoryAndSalesMilestonesAndTieredRoyalties" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="debit" />
  <xsd:element name="IncomeLossOnU.s.DomesticSalesSharePercentage" id="ptct_IncomeLossOnU.s.DomesticSalesSharePercentage" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" />
  <xsd:element name="CollaborationAndLicenseRevenueMember" id="ptct_CollaborationAndLicenseRevenueMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="EmflazaAndKebilidiMember" id="ptct_EmflazaAndKebilidiMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="ContractWithCustomerCollaborationRevenueRefund" id="ptct_ContractWithCustomerCollaborationRevenueRefund" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="debit" />
  <xsd:element name="OtherExpenseSegmentNet" id="ptct_OtherExpenseSegmentNet" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="debit" />
  <xsd:element name="OtherProductsMember" id="ptct_OtherProductsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="AllOtherCountriesOtherThanRussiaBrazilAndUnitedStatesMember" id="ptct_AllOtherCountriesOtherThanRussiaBrazilAndUnitedStatesMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="CensaMergerAgreementMember" id="ptct_CensaMergerAgreementMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="SephienceMember" id="ptct_SephienceMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="PercentageOfNetProductSales" id="ptct_PercentageOfNetProductSales" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" />
  <xsd:element name="CostOfGoodsAndServiceExcludingAmortizationOfIntangibleAssets" id="ptct_CostOfGoodsAndServiceExcludingAmortizationOfIntangibleAssets" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="debit" />
  <xsd:element name="NumberOfDistributors" id="ptct_NumberOfDistributors" type="xbrli:integerItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" />
  <xsd:element name="LiabilityDevelopmentAndRegulatoryMilestonesMember" id="ptct_LiabilityDevelopmentAndRegulatoryMilestonesMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="RightsSatisfactionAgreementMember" id="ptct_RightsSatisfactionAgreementMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="RightsForfeiturePercentageOfAnnualNetSalesPayable" id="ptct_RightsForfeiturePercentageOfAnnualNetSalesPayable" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" />
  <xsd:element name="AnnualNetSalesLessThanOrEqualTo250MillionMember" id="ptct_AnnualNetSalesLessThanOrEqualTo250MillionMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="AnnualNetSalesGreaterThan250MillionButLessThan500MillionMember" id="ptct_AnnualNetSalesGreaterThan250MillionButLessThan500MillionMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="AnnualNetSalesGreaterThan500MillionMember" id="ptct_AnnualNetSalesGreaterThan500MillionMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="MaximumUpfrontConsiderationAgreedToBePaid" id="ptct_MaximumUpfrontConsiderationAgreedToBePaid" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" xbrli:balance="credit" />
  <xsd:element name="MaximumAdditionalMilestonePayableForEachRightHolder" id="ptct_MaximumAdditionalMilestonePayableForEachRightHolder" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" xbrli:balance="credit" />
  <xsd:element name="MaximumAdditionalMilestonePayableForRightHolders" id="ptct_MaximumAdditionalMilestonePayableForRightHolders" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" xbrli:balance="credit" />
  <xsd:element name="OwnershipPercentagePriorToMergerAgreement" id="ptct_OwnershipPercentagePriorToMergerAgreement" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" />
  <xsd:element name="PaymentOfUpfrontConsideration" id="ptct_PaymentOfUpfrontConsideration" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="credit" />
  <xsd:element name="AdditionalMilestonePaymentObligation" id="ptct_AdditionalMilestonePaymentObligation" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" xbrli:balance="credit" />
  <xsd:element name="ThresholdConsecutiveCalendarPeriodOfFirstOccurrenceOfMilestone" id="ptct_ThresholdConsecutiveCalendarPeriodOfFirstOccurrenceOfMilestone" type="xbrli:durationItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" />
  <xsd:element name="UponFirstOccurrenceOfThreeOrFewerConsecutiveCalendarYearPeriodMember" id="ptct_UponFirstOccurrenceOfThreeOrFewerConsecutiveCalendarYearPeriodMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="MinimumAggregateNetProductSalesOverThresholdConsecutivePeriod" id="ptct_MinimumAggregateNetProductSalesOverThresholdConsecutivePeriod" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="credit" />
  <xsd:element name="UponFirstOccurrenceOfFiveOrFewerConsecutiveCalendarYearPeriodMember" id="ptct_UponFirstOccurrenceOfFiveOrFewerConsecutiveCalendarYearPeriodMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="UponFirstOccurrenceOfSevenOrFewerConsecutiveCalendarYearPeriodMember" id="ptct_UponFirstOccurrenceOfSevenOrFewerConsecutiveCalendarYearPeriodMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="UponFirstOccurrenceOfNineOrFewerConsecutiveCalendarYearPeriodMember" id="ptct_UponFirstOccurrenceOfNineOrFewerConsecutiveCalendarYearPeriodMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="UponFirstOccurrenceOfElevenOrFewerConsecutiveCalendarYearPeriodMember" id="ptct_UponFirstOccurrenceOfElevenOrFewerConsecutiveCalendarYearPeriodMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="GlennD.SteeleJr.Member" id="ptct_GlennD.SteeleJr.Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="ScheduleOfShareBasedPaymentArrangementPerformanceBasedRestrictedStockUnitsGrantedTableTextBlock" id="ptct_ScheduleOfShareBasedPaymentArrangementPerformanceBasedRestrictedStockUnitsGrantedTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" />
  <xsd:element name="UpstazaAndKebilidiMember" id="ptct_UpstazaAndKebilidiMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWithPerformanceBasedConditionsSatisfied" id="ptct_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWithPerformanceBasedConditionsSatisfied" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" />
  <xsd:element name="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWithPerformanceBasedConditionsWeightedAverageGrantDateFairValue" id="ptct_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWithPerformanceBasedConditionsWeightedAverageGrantDateFairValue" type="dtr-types:perShareItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" />
  <xsd:element name="StephanieOkeyMember" id="ptct_StephanieOkeyMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="PercentageOfFutureRoyaltiesSold" id="ptct_PercentageOfFutureRoyaltiesSold" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" />
  <xsd:element name="NumberOfPotentialPurchasePricePayments" id="ptct_NumberOfPotentialPurchasePricePayments" type="xbrli:integerItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" />
  <xsd:element name="ContingentRoyaltyPurchasePricePayment" id="ptct_ContingentRoyaltyPurchasePricePayment" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="credit" />
  <xsd:element name="IfRoyaltyPharmaReceivesGreaterThan347MillionOfAssignedRoyaltiesIn2027Member" id="ptct_IfRoyaltyPharmaReceivesGreaterThan347MillionOfAssignedRoyaltiesIn2027Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="IfRoyaltyPharmaReceivesGreaterThan363MillionOfAssignedRoyaltiesIn2028Member" id="ptct_IfRoyaltyPharmaReceivesGreaterThan363MillionOfAssignedRoyaltiesIn2028Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="IfRoyaltyPharmaReceivesGreaterThan379MillionOfAssignedRoyaltiesIn2029Member" id="ptct_IfRoyaltyPharmaReceivesGreaterThan379MillionOfAssignedRoyaltiesIn2029Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="AssignedRoyaltyPaymentsThreshold" id="ptct_AssignedRoyaltyPaymentsThreshold" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="credit" />
  <xsd:element name="DecreaseInOperatingLeaseRightOfUseAssetsRelatedToLeaseModificationsAndTerminations" id="ptct_DecreaseInOperatingLeaseRightOfUseAssetsRelatedToLeaseModificationsAndTerminations" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="credit" />
  <xsd:element name="DecreaseInOperatingLeaseLiabilityRelatedToLeaseModificationsAndTerminations" id="ptct_DecreaseInOperatingLeaseLiabilityRelatedToLeaseModificationsAndTerminations" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="debit" />
  <xsd:element name="DevelopmentMilestoneRemainingPotentialContingentMilestonePayments" id="ptct_DevelopmentMilestoneRemainingPotentialContingentMilestonePayments" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" xbrli:balance="credit" />
  <xsd:element name="DevelopmentMilestoneObligationRevenueReceived" id="ptct_DevelopmentMilestoneObligationRevenueReceived" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="debit" />
  <xsd:element name="AdjustmentsToAdditionalPaidInCapitalRepurchaseOfConvertibleSecurities" id="ptct_AdjustmentsToAdditionalPaidInCapitalRepurchaseOfConvertibleSecurities" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="debit" />
  <xsd:element name="InducementExpenseOnRepurchaseOfConvertibleSecurities" id="ptct_InducementExpenseOnRepurchaseOfConvertibleSecurities" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="debit" />
  <xsd:element name="PaymentsForConversionOfDebt" id="ptct_PaymentsForConversionOfDebt" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="credit" />
  <xsd:element name="MichaelSchmertzlerMember" id="ptct_MichaelSchmertzlerMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="Phase3VotoplamTrialMember" id="ptct_Phase3VotoplamTrialMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="NumberOfIndividualsExpectedToEnrollInClinicalTrial" id="ptct_NumberOfIndividualsExpectedToEnrollInClinicalTrial" type="xbrli:integerItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" />
  <xsd:element name="RandomizationRatioClinicalTrial" id="ptct_RandomizationRatioClinicalTrial" type="xbrli:pureItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" />
  <xsd:element name="TreatmentDosageClinicalTrial" id="ptct_TreatmentDosageClinicalTrial" type="xbrli:integerItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" />
  <xsd:element name="InterimAnalysisPeriodClinicalTrial" id="ptct_InterimAnalysisPeriodClinicalTrial" type="xbrli:durationItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" />
  <xsd:element name="TreatmentComparisonPeriodClinicalTrial" id="ptct_TreatmentComparisonPeriodClinicalTrial" type="xbrli:durationItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" />
  <xsd:element name="DiseaseProgressionSlowingPercentage" id="ptct_DiseaseProgressionSlowingPercentage" type="xbrli:pureItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" />
  <xsd:element name="ProveFaStudyMember" id="ptct_ProveFaStudyMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="EligibleAgeClinicalTrial" id="ptct_EligibleAgeClinicalTrial" type="xbrli:integerItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" />
  <xsd:element name="StudyDurationClinicalTrial" id="ptct_StudyDurationClinicalTrial" type="xbrli:durationItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" />
  <xsd:element name="ConvertibleSeniorNotes0Due2031Member" id="ptct_ConvertibleSeniorNotes0Due2031Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="DebtInstrumentAdditionalAmountAvailableForPurchase" id="ptct_DebtInstrumentAdditionalAmountAvailableForPurchase" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" xbrli:balance="credit" />
  <xsd:element name="ThresholdRevenueToTriggerMilestonePayment" id="ptct_ThresholdRevenueToTriggerMilestonePayment" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="credit" />
  <xsd:element name="ConvertibleSeniorNotes0PercentDue2031Member" id="ptct_ConvertibleSeniorNotes0PercentDue2031Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="DebtInstrumentRedemptionPeriodOnOrAfterJune202029Member" id="ptct_DebtInstrumentRedemptionPeriodOnOrAfterJune202029Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="ExcessOfFairValueOfRepurchasePriceOverIfConvertedValue" id="ptct_ExcessOfFairValueOfRepurchasePriceOverIfConvertedValue" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="debit" />
  <xsd:element name="DerecognitionOfDebtDifferenceOfIfConvertedValueAndNetCarryingAmount" id="ptct_DerecognitionOfDebtDifferenceOfIfConvertedValueAndNetCarryingAmount" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="debit" />
  <xsd:element name="ExcessOfConversionValueOverCarryingAmount" id="ptct_ExcessOfConversionValueOverCarryingAmount" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="debit" />
</xsd:schema>
