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  <xsd:element id="ptct_AccruedConsultingAndContractedResearchCurrent" name="AccruedConsultingAndContractedResearchCurrent" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element id="ptct_AccruedSeverance" name="AccruedSeverance" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element id="ptct_AvailableForSaleSecuritiesDebtMaturitiesOverOneYearFairValue" name="AvailableForSaleSecuritiesDebtMaturitiesOverOneYearFairValue" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element id="ptct_ChangeInUnrealizedGainLossOnMarketableSecurities" name="ChangeInUnrealizedGainLossOnMarketableSecurities" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element id="ptct_CollaborationAndGrantRevenue" name="CollaborationAndGrantRevenue" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element id="ptct_ConvertibleInstrumentsPrincipalAndUnpaidInterestPayableUponEventsOfDefault" name="ConvertibleInstrumentsPrincipalAndUnpaidInterestPayableUponEventsOfDefault" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ptct_ConvertibleSeniorNotes3.0PercentDue2022Member" name="ConvertibleSeniorNotes3.0PercentDue2022Member" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ptct_DebtInstrumentConversionPeriodOnOrAfterAugust202018Member" name="DebtInstrumentConversionPeriodOnOrAfterAugust202018Member" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="ptct_DebtInstrumentConvertibleThresholdBusinessDays" name="DebtInstrumentConvertibleThresholdBusinessDays" nillable="true" substitutionGroup="xbrli:item" type="xbrli:durationItemType" xbrli:periodType="duration" />
  <xsd:element id="ptct_DebtInstrumentConvertibleThresholdConsecutiveTradingDayPeriod" name="DebtInstrumentConvertibleThresholdConsecutiveTradingDayPeriod" nillable="true" substitutionGroup="xbrli:item" type="xbrli:durationItemType" xbrli:periodType="duration" />
  <xsd:element id="ptct_DebtInstrumentConvertibleThresholdSalePriceOfCommonStockConversionRateProductPercentageMaximum" name="DebtInstrumentConvertibleThresholdSalePriceOfCommonStockConversionRateProductPercentageMaximum" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="instant" />
  <xsd:element id="ptct_DebtInstrumentPrincipalAmountDenominationForConversionIntoCommonStock" name="DebtInstrumentPrincipalAmountDenominationForConversionIntoCommonStock" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ptct_DepositsAndOtherAssetsMember" name="DepositsAndOtherAssetsMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="ptct_DepositsAndOtherAssetsNoncurrent" name="DepositsAndOtherAssetsNoncurrent" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element id="ptct_DevelopmentAndRegulatoryMilestonePaymentObligations" name="DevelopmentAndRegulatoryMilestonePaymentObligations" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element abstract="true" id="ptct_DocumentAndEntityInformationAbstract" name="DocumentAndEntityInformationAbstract" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element id="ptct_EmployeeDirectorAndConsultantStockOptionPlanMember" name="EmployeeDirectorAndConsultantStockOptionPlanMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ptct_EmployeeStockPurchasePlanMember" name="EmployeeStockPurchasePlanMember" 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_FairValueAssetsTransfersBetweenLevel1AndLevel2Amount" name="FairValueAssetsTransfersBetweenLevel1AndLevel2Amount" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element id="ptct_GrossProfitMargin" name="GrossProfitMargin" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="instant" />
  <xsd:element id="ptct_InventoriesAndCostOfRevenuePolicyTextBlock" name="InventoriesAndCostOfRevenuePolicyTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ptct_LongTermIncentivePlan2013Member" name="LongTermIncentivePlan2013Member" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="ptct_MinimumAgeOfAmbulatoryPatient" name="MinimumAgeOfAmbulatoryPatient" nillable="true" substitutionGroup="xbrli:item" type="xbrli:durationItemType" xbrli:periodType="duration" />
  <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 id="ptct_NumberOfStatesInEuropeanEconomicArea" name="NumberOfStatesInEuropeanEconomicArea" nillable="true" substitutionGroup="xbrli:item" type="xbrli:integerItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ptct_ResearchAndDevelopmentAndSellingGeneralAndAdministrativeExpensesMember" name="ResearchAndDevelopmentAndSellingGeneralAndAdministrativeExpensesMember" 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_ScheduleOfInterestExpenseRecognizedRelatedToConvertibleDebt" name="ScheduleOfInterestExpenseRecognizedRelatedToConvertibleDebt" 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 abstract="true" id="ptct_WellcomeTrustLimitedMember" name="WellcomeTrustLimitedMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
</xsd:schema>
