Phase 3 Fabry Monotherapy Study (Study 011) Results Conference Call April 29, 2014

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Study 011 12- and 24-Month Data - Key Findings Subjects who switched from placebo to migalastat after month 6 demonstrated a statistically significant reduction in kidney interstitial capillary GL-3 at month 12 (p=0.013*) Subjects who remained on migalastat for 12 months demonstrated a durable reduction in kidney interstitial capillary GL-3 Reduction in disease substrate also observed in plasma lyso-Gb3 in subjects who switched from placebo to migalastat (p<0.0001**). Subjects who remained on migalastat demonstrated a durable reduction in lyso-Gb3 Kidney function (estimated glomerular filtration rate (eGFR), iohexol mGFR) remained stable over 18-24 months Migalastat was generally safe and well-tolerated Of 41 subjects with GLP HEK amenable mutations who completed Study 011, 35 (85%) remain in voluntary extension study (Study 041) Migalastat Demonstrated Statistically Significant and Durable Substrate Reductions on 12-Month Pre-Specified Primary Analysis in Fabry Patients with Amenable Mutations *MMRM, **ANCOVA

Phase 3 FACETS Study (Study 011) 67 patients 1:1 Randomization Stratified by gender Month 7-12 Open-Label Follow-Up Period Month 13-24 Placebo QOD Migalastat 150 mg QOD Open-Label Migalastat 150 mg QOD Slide 4 Month 0-6 Double-Blind Treatment Period Stage 1* Stage 2* Optional Extension** 12-Month Biopsy and 24-Month Clinical Data Are Being Reported Today *GL-3 Substrate Measured by Histology in Kidney Biopsies **Clinical Outcomes Assessed, Including eGFR and Proteinuria 6-month primary endpoint: kidney interstitial capillary GL-3 12-month biopsy and 24-month clinical data (NEW DATA) Pre-Specified GLP HEK Amenable Subgroup Analysis

1 Difference=12.5% (95% CI: -13.4, 37.3). Migalastat HCl minus placebo in % responders. P-value based on exact Cochran-Mantel-Haenszel test stratified by gender. Subjects with baseline biopsy but missing month 6 biopsy counted as a failure. P=0.31 9/32 13/32 Top-Line Stage 1 (6-Month) Results (Reported December 2012) Primary Endpoint - Responder Analysis (ITT): > 50% Reduction from Baseline in Kidney Interstitial Capillary GL-3 % Responders

6-Month Post-Hoc Analysis (Reported February 2014) Statistically Significant Mean Change in Kidney Interstitial Capillary GL-3 Compared to Placebo (GLP HEK Amenable)* Mean Inclusions Per Capillary1 Baseline Month 6 +0.07 ± 0.13 -0.25 ± 0.10 P=0.0082 *All patients with evaluable paired biopsies and amenable GLA mutations in GLP-validated HEK assay – post hoc at month 6 and pre-specified at month 12 1Data points are baseline corrected; represent mean ± standard error (SEM) change from baseline in the mean number of GL-3 inclusions per capillary after 6 months of treatment with migalastat or placebo. 2Analysis of covariance (ANCOVA) model with covariate adjustment for baseline value and factors for treatment group and treatment by baseline interaction. P-value corresponding to least-square mean difference between migalastat and placebo is displayed. 0.4 0.0 -0.2 -0.4 0.2 Migalastat (n=25) Placebo (n=20)

12-Month Pre-Specified Primary Analysis Statistically Significant Mean Change in Kidney Interstitial Capillary GL-3 in Patients Switching from Placebo to Migalastat HCl (GLP HEK Amenable)* Mean Inclusions Per Capillary1 Baseline Month 6 +0.07 ± 0.13 -0.25 ± 0.10 P=0.0082 *All patients with evaluable paired biopsies and amenable GLA mutations in GLP-validated HEK assay – post hoc at month 6 and pre-specified at month 12 1Data points are baseline corrected; represent mean ± standard error (SEM) change from baseline in the mean number of GL-3 inclusions per capillary after 6 months of treatment with migalastat or placebo. 2Analysis of covariance (ANCOVA) model with covariate adjustment for baseline value and factors for treatment group and treatment by baseline interaction. P-value corresponding to least-square mean difference between migalastat and placebo is displayed. 3MMRM Pbo change M6 to M12. Month 12 -0.31 ± 0.10 +0.01 ± 0.011 P=0.0133 0.4 0.0 -0.2 -0.4 0.2 Placebo -> Migalastat (n=17) Migalastat -> Migalastat (n=25,22) Placebo (n=20)

Disease Substrate in Plasma (Plasma Lyso-GB3) Statistically Significant Reduction in Plasma Lyso-GB3 at Month 6 and Month 12 Following Treatment with Migalastat (GLP HEK Amenable)* 5.0 -5.0 -10.0 -15.0 10.0 Plasma Lyso-GB31 Baseline Month 6 +0.60 ± 2.4 -11.2±4.8 P=0.00332 -20.0 0.0 *Patients with amenable GLA mutations in GLP-validated HEK assay 1Baseline corrected. Error bars are SEM 2ANCOVA comparing migalstat to placebo in Stage 1 3ANCOVA comparing change from month 6 to month 12 in subjects switching from placebo to migalastat Month 12 +1.2 ±1.3 P<0.00013 Placebo -> Migalastat (n=13) Migalastat -> Migalastat (n=18,18) -15.5±6.2 Placebo (n=13) -25.0

GFR Remained Stable Over 18-24 Months (GLP HEK Amenable)* Annualized GFR (ml/min/m2/yr) at Month 18 or 241 GFR Measure N* Mean (SEM) eGFR (CKD-EPI) 41 -0.30 (0.66) eGFR (MDRD) 41 0.79 (1.03) mGFR (iohexol) 37 -1.51 (1.33) Kidney Function: Annualized Glomerular Filtration Rate (GFR) *Patients with amenable GLA mutations in GLP-validated HEK assay 124 Months of Data in Subjects Treated with Migalastat from Baseline, 18 Months of Data in Subjects Switched from Placebo to Migalastat After 6 Months

Safety Summary Most Common Treatment Emergent Adverse Events (> 10% of Subjects) Adverse event Baseline to Month 6 Months 7-12 Open-Label Extension (Months 13-24) Placebo* (n=33) Migalastat (n=34) Placebo-Migalastat* (n=30) Migalastat (n=33) Placebo-Migalastat* (n=28) Migalastat (n=29) Any Event 91% 91% 80% 79% 86% 83% Headache 21% 35% 11% 10% Fatigue 12% 12% Nausea 9% 12% Nasopharyngitis 6% 15% Paresthesia 12% 9% Procedural Pain 10% 12% Proteinuria 18% 14% Bronchitis 11% 10% Migalastat Generally Safe and Well Tolerated *Subjects Received Placebo from Baseline to Month 6, Switched to Migalastat After Month 6

Global Regulatory Strategy Totality of clinical data 8+ years of data in extension studies Complete data from Phase 3 Studies (011 and 012) Clear regulatory pathway Non-inferiority to ERT (Study 012)

Patient Experience 97 Patients Today Take Migalastat HCl as Only Therapy for Fabry Disease1 1 All patients are receiving migalastat as part of ongoing clinical trials as of March 1, 2014 *Retention defined as # of patients who complete a study and chose to enter extension, e.g., 011 12-mo into 24-mo extension Total subjects on migalastat today: 97 Total patient years of therapy: 330 (no drug-related SAEs) Maximum years on therapy: 8 years Average retention rate into next study*: 94% Total subjects who have ever taken migalastat: 137

Key Milestones Timing Milestone 3Q09 Phase 3 Study 011 initiation 3Q11 Phase 3 Study 012 initiation 4Q12 Interim 6-month data from first Phase 3 Study (011) 2Q13 FDA meeting (Type C) 2Q14 12-month Study 011 data (kidney biopsies) 2Q14 24-month Study 011 data (clinical outcomes) 3Q14 18-month Study 012 data (kidney function)