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J O U R N A L O F T H E A M E R I C A N C O L L E G E O F C A R D I O L O G Y V O L . 6 8 , N O . 2 3 , 2 0 1 6

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Later Onset Fabry Disease,Cardiac Damage Progress in SilenceExperience With a Highly Prevalent Mutation

Ting-Rong Hsu, MD,a,b Sheng-Che Hung, MD,c,d,e Fu-Pang Chang, MD,f Wen-Chung Yu, MD,g Shih-Hsien Sung, MD,g

Chia-Lin Hsu, PHD,h Ivan Dzhagalov, PHD,h Chia-Feng Yang, MD,b,i Tzu-Hung Chu, MD,b Han-Jui Lee, MD,c

Yung-Hsiu Lu, BS,b Sheng-Kai Chang, PHD,b Hsuan-Chieh Liao, BS,j Hsiang-Yu Lin, MD, PHD,k Tsan-Chieh Liao, MD,l

Pi-Chang Lee, MD,b Hsing-Yuan Li, MD, PHD,b An-Hang Yang, MD, PHD,f Hui-Chen Ho, BS,m Chuan-Chi Chiang, PHD,j

Ching-Yuang Lin, MD, PHD,n Robert J. Desnick, MD, PHD,o Dau-Ming Niu, MD, PHDa,b,p,q

ABSTRACT

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BACKGROUND Recently, several studies revealed a much higher prevalence of later onset Fabry disease (FD) than

previously expected. It suggested that later onset FD might present as an important hidden health issue in certain ethnic

or demographic populations in the world. However, the natural history of its phenotype has not been systemically

investigated, especially the cardiac involvement.

OBJECTIVES The study analyzed a large-scale newborn screening program for FD to understand the natural course of

later onset FD.

METHODS To date, 916,383 newborns have been screened for FD in Taiwan, including more than 1,200 individuals with

the common, later onset IVS4þ919G>A (IVS4) mutation. Echocardiography was performed in 620 adults with the IVS4

mutation to analyze the prevalence of left ventricular hypertrophy (LVH), and gadolinium-enhanced cardiac magnetic

resonance imaging was performed in 129 patients with FD, including 100 IVS4 adults.

RESULTS LVH was observed in 67% of men and 32% of women older than 40 years. Imaging evidenced significant late

gadolinium enhancement in 38.1% of IVS4 men and 16.7% of IVS4 women with the IVS4 mutation but without LVH.

Seventeen patients underwent endomyocardial biopsies, which revealed significant globotriaosylceramide substrate

accumulation in their cardiomyocytes.

CONCLUSIONS Significant cardiomyocyte substrate accumulation in IVS4 patients led to severe and irreversible cardiac

fibrosis before development of LVH or other significant cardiac manifestations. Thus, it might be too late to start enzyme

replacement therapy after the occurrence of LVH or other significant cardiac manifestations in patients with later onset

FD. This study also indicated the importance of newborn screening for early detection of the insidious, ongoing,

irreversible cardiac damage in patients with later onset FD. (J Am Coll Cardiol 2016;68:2554–63)

© 2016 by the American College of Cardiology Foundation.

m the aInstitute of Clinical Medicine, National Yang-Ming University, Taipei, Taiwan; bDepartment of Pediatrics, Taipei Vet-

ns General Hospital, Taipei, Taiwan; cDepartment of Radiology, Taipei Veterans General Hospital, Taipei, Taiwan; dSchool of

dicine, National Yang Ming University, Taipei, Taiwan; eDepartment of Biomedical Imaging and Radiological Sciences, National

ng Ming University, Taipei, Taiwan; fPathology and Laboratory Medicine Department, Taipei Veterans General Hospital, Taipei,

iwan; gDivision of Cardiology, Department of Medicine, Taipei Veterans General Hospital and National Yang-Ming University,

ool of Medicine, Taipei, Taiwan; hInstitute of Microbiology and Immunology, National Yang-Ming University, Taipei, Taiwan;

stitute of Environmental and Occupational Health Sciences, National Yang-Ming University, Taipei, Taiwan; jNeonatal

eening Center, Chinese Foundation of Health, Taipei, Taiwan; kDepartment of Pediatrics, Mackay Memorial Hospital and

partment of Medicine, Mackay Medical College, Taipei, Taiwan; lDepartment of Radiology, Zhongxiao Branch, Taipei City

spital, Taipei, Taiwan; mTaipei Institute of Pathology, Taipei, Taiwan; nCollege of Medicine, China Medical University,

ichung, Taiwan; oDepartment of Genetics & Genomic Sciences, The Icahn School of Medicine at Mount Sinai, New York,

w York; pTaiwan Clinical Trial Consortium in Fabry Disease, Taipei, Taiwan; and the qDepartment of Medical Research,

ipei Veterans General Hospital, Taipei, Taiwan. This work was partly supported by the National Science Council, Taiwan

o. NSC-100-2325-B-010-014) and Taipei Veterans General Hospital (No. V101C-129 and V101C-187). Dr. Desnick has served as

AB BR E V I A T I O N S

AND ACRONYM S

CAD = coronary artery disease

ERT = enzyme replacement

therapy

FD = Fabry disease

Gal A = galactosidase A

J A C C V O L . 6 8 , N O . 2 3 , 2 0 1 6 Hsu et al.D E C E M B E R 1 3 , 2 0 1 6 : 2 5 5 4 – 6 3 Cardiac Fibrosis Without Hypertrophy in Fabry Disease

2555

F abry disease (FD), an X-linked lysosomal stor-age disorder (MIM 301500), results from muta-tions in the a-galactosidase A gene (GLA) that

cause deficient a-galactosidase A (a-Gal A) activityand the progressive systematic accumulation ofglobotriaosylceramide (Gb3) and related glycos-phingolipids, particularly in lysosomes of the heart,kidneys, skin, and brain.

SEE PAGE 2564

Gb3 = globotriaosylceramide

GE-CMR = gadolinium-enhanced

cardiac magnetic resonance

GLA = a-galactosidase A gene

HCM = hypertrophic

cardiomyopathy

IVS4 = IVS4D919G>A

LGE = late gadolinium

enhancement

LVH = left ventricular

hypertrophy

LVM = left ventricular mass

LVMI = left ventricular mass

The disease has 2 major phenotypes, the classic(type 1) and the later onset (type 2) subtypes (1–5). Onthe basis of recent newborn screening studies, theincidence of patients with the later onset phenotypeis much higher than that of the classic phenotype(6–12). Affected boys with the type 1 classic pheno-type have little or no a-Gal A activity and have onsetof acroparesthesias, hypohidrosis, angiokeratomas,or a characteristic corneal dystrophy in childhood oradolescence (13). As they age, affected men with thetype 1 phenotype develop progressive multisystemicinvolvement leading to renal failure, hypertrophiccardiomyopathy (HCM), or cerebrovascular disease(1). Men with the type 2 later onset phenotype haveresidual a-Gal A activity, little or no vascular endo-thelial Gb3 accumulation, and lack of the early clin-ical manifestations of patients with the type 1phenotype (1–3,14). However, type 2 men developsevere cardiac disease or renal failure in the fourth toseventh decades of life (1–3,14). Of interest, andwithout a current explanation, the type 2 phenotypetends to have mutation-specific cardiac or kidneyinvolvement, although some men develop both withage (15).

Here, we report the findings in patients with thetype 2 mutation IVS4þ919G>A (IVS4) that primarilypresents with progressive cardiac involvement,leading to HCM and eventual heart failure. In Taiwan,we initiated newborn screening for FD, and found theIVS4 mutation was unusually frequent, occurring inabout 1 in 1,600 boys (7). As of December 2015, morethan 1,200 individuals with the IVS4 mutation hadbeen identified at our center.

The natural course of the type 2 phenotype withprimary cardiac disease is largely unknown, but un-derstanding the early signs of cardiac involvement isrelevant to determining when to initiate enzyme

a consultant for Genzyme/Sanofi, Amicus Therapeutics, and Sangamo BioSci

owns stock options in Sangamo BioSciences; and receives royalties from Gen

reported that they have no relationships relevant to the contents of this pap

equally to this work. Michelle Kitteson, MD, PhD, served as Guest Editor fo

Manuscript received June 10, 2016; revised manuscript received August 29,

replacement therapy (ERT) to improve thecardiac outcome. Moreover, there are nowell-established treatment guidelines fortype 2 cardiac patients. In Taiwan, ERT can beinitiated only after presence of HCM or sig-nificant cardiac impairment. However, recentstudies revealed that for long-term improve-ment in myocardial morphology and func-tion, ERT should be initiated beforemyocardial fibrosis has developed (16,17). Tofurther our understanding of the pathogen-esis of the type 2 cardiac phenotype and toupdate treatment guidelines, we usedgadolinium-enhanced cardiac magnetic reso-nance (GE-CMR) imaging to investigate thedevelopment of myocardial fibrosis in pa-tients with or without cardiac hypertrophy.

METHODS

The methodology and results of the newborn

screening program for FD in Taiwan have been pre-viously described (7,18). From January 1, 2008, toDecember 31, 2015, a total of 916,383 newborns werescreened.

Since 2008, 620 adults with the IVS4 mutation—identified through screening the families of newbornswith the IVS4 mutation—were enrolled in this study.All participants were examined by 2 experienced car-diologists who were blind to those with a GLA muta-tion. Echocardiography was performed in accordwith the recommendations of the American Societyof Echocardiography using ACUSON equipment(Antares, Siemens AG, Munich, Germany; Sono 7500,Hewlett-Packard Company, Palo Alto, California). Leftventricular mass (LVM) was calculated according tothe Devereux cube formula (19). LVM was normalizedto height (m) to 2.7 power (left ventricular mass index[LVMI] ¼ LVM/height2.7) (20). Left ventricular hyper-trophy (LVH) was defined as LVMI >51 g/m2.7 in menand LVMI >48 g/m2.7 in women (21).

Since 2010, a total of 129 patients with FD havebeen enrolled in GE-CMR studies (57.4% men; 54.0 �12.3 years of age, range 19 to 83 years of age). Therewere 100 IVS4 patients (64 men), 22 type 1 patients(5 men), and 7 type 2 patients with primarily renalinvolvement (5 men). All of the IVS4 participants

index

ences; owns founder shares of Amicus Therapeutics;

zyme/Sanofi and Shire HGT. All other authors have

er to disclose. Drs. T.-R. Hsu and Hung contributed

r this article.

2016, accepted September 9, 2016.

TABLE 1 Newborn Screening for Fabry Disease

Boys Girls Total

DBS in newborns 476,909 439,474 916,383

First DBS test positive* 3,765 (0.79) 6,328 (1.44) 10,093 (1.10)

Second DBS test positive† 505 (0.11) 431 (0.10) 936 (0.10)

Identification of the mutations,n (incidence)‡

324 (1/1,471) 117 (1/3,756) 441 (1/2,078)

Values are N or n (%) unless otherwise indicated. Screening was from Taiwan, January 2008 throughDecember 2015. *a-Galactosidase A (Gal A) activity<3 mmol/h/l. †a-Gal A activity<2 mmol/h/l. ‡Deficient plasmaa-Gal A activity and identification of a-Gal A mutation.

DBS ¼ dried blood spot.

Hsu et al. J A C C V O L . 6 8 , N O . 2 3 , 2 0 1 6

Cardiac Fibrosis Without Hypertrophy in Fabry Disease D E C E M B E R 1 3 , 2 0 1 6 : 2 5 5 4 – 6 3

2556

were 35 years of age or older, whereas the non-IVS4participants were 18 years or older.

All study subjects underwent GE-CMR using a3.0-T scanner (Discovery MR750, GE Healthcare,Milwaukee, Wisconsin). In addition to routine cinemagnetic resonance imaging, a breath-hold electro-cardiogram (ECG)-gated 2-dimensional myocardialdelayed enhancement sequence (8 mm slice thick-ness; both short-axis and 4-chamber views; fieldof view, 340 � 316 mm; matrix, 256 � 192) was appliedto detect myocardial late gadolinium enhancement 10min after intravenous administration of 0.1 mmol kg–1

gadobutrol (17). LVH assessed by GE-CMR wasdefined by an LVMI of >39 g/m2.7 in women or>48 g/m2.7 in men (22). Important cardiac parameters,such as posterior and interventricular wall thicknessand ejection fraction, were calculated (23).

ENDOMYOCARDIAL BIOPSY AND HISTOLOGIC

STUDIES. As required by the Taiwan treatmentguidelines for FD, all IVS4 patients applying for ERTfunding from the National Health Insurancemust undergo endomyocardial biopsy to demonstratethat FD was the primary cause of their cardiomyopa-thy. Seventeen IVS4 patients who had myocardialfibrosis without LVH underwent endomyocardial bi-opsy. According to previous autopsy studies of car-diac Fabry patients, the Fabry pathologic changes inthe right ventricle were usually milder than those inthe left ventricle (24). However, right heart cathe-terization and right interventricular septum biopsywas chosen for this study because right ventricle bi-opsy is safer and easier than left ventricle biopsy. Inaddition, coronary angiography was performed inpatients with the IVS4 mutation if they had a risk ofcoronary artery disease (CAD) and provided informedconsent. CAD was defined as coronary stenosis and>50% narrowing in luminal diameter. Regardingcardiac biopsy, catheterization was approached viathe right internal jugular vein under digital x-rayguidance. A flexible endomyocardial bioptome wasinserted into the right ventricle and 2 to 3 specimens

were obtained from interventricular septum andsubmitted for histological examination.

Cardiac specimens were fixed in 10% bufferedformalin and embedded in paraffin. The sectionswere stained with hematoxylin and eosin and Mas-son’s trichrome, then subjected to light microscopicanalysis. For electron microscopy, tissues were fixedin 2.5% glutaraldehyde in phosphate buffer, post-fixed with 1% osmium tetroxide in Sorenson’s phos-phate buffer, followed by dehydration through agraded series of ethanol washes, and embedded inSpurr’s Epon. Semithin sections were cut from theblock and stained with toluidine blue for microscopicreview. Ultrathin sections were then prepared andexamined by electron microscopy.

STATISTICAL ANALYSIS. Descriptive statistics(mean � SD) were used to describe the basic featuresof the data in this study. Due to the small number ofpatients and the uncontrolled nature of this study, noinferential statistics were used. Results were pre-sented as actual measurements from individual pa-tients. SPSS version 20 (IBM Corporation, Armonk,New York) was used for descriptive statistics.

RESULTS

Of the 916,383 newborns screened over 7 years,476,909 (52%) were boys and 439,474 (48%) weregirls. A total of 441 newborns (324 boys) had lowplasma a-Gal A activity and a GLA mutation (Table 1),including 381 with an IVS4 mutation, 7 with type 1classic mutations, 16 with type 2 later onset muta-tions, and 37 with novel mutations. Subsequentfamily studies identified >1,400 individuals withthese mutations, of whom 83.5% (>1,200) had thetype 2 mutation, IVS4þ919G>A.

We investigated the age at which LVH was detectedin men and women with the IVS4 mutation. Only2 men (4%) and 3 women (2%) <40 years of age hadborderline LVH. However, the onset of LVH increasedrapidly in the IVS4 adults who were >40 years of agefor both men and women. Actually, about 67% ofmale and 32% of female adults older than 40 years ofage had developed LVH (Figure 1).

IMAGING AND BIOPSY. Of 100 IVS4 participants, 28(22 men) had LVH on GE-CMR, whereas 72 IVS4(42 men) did not. GE-CMR in adults with LVHrevealed that 17 of 22 (77.3%) men and no women hadlate gadolinium enhancement (LGE), whereas 16 of 42(38.1%) men and 5 of 30 (16.7%) women without LVHhad LGE. Of note, 2 IVS4 men <40 years of age hadsignificant LGE on GE-CMR, but without LVH.

Of 5 men with the type 1 classic phenotype, 2 hadLVH without LGE and 1 man had LGE without LVH.

FIGURE 1 LVH Onset Rate

Num

bers

of P

atie

nts

Percents of Disease Onset (%)

A

Age

Males

0

10

0%

20%

40%

60%

80%

100%

4%

29%

53%

78%

100%

20

40

30

50

60

2

48

12

5 9

8

11

40

10

30-39 40-49 50-59 60-69 70-79

Percents of Disease Onset (%)

Num

bers

of P

atie

nts

B

Age

Females

0 0%

20%

40%

60%

80%

100%

40

120

80

160

200

3

187

43 42

16

36

28

8 6

4

4

2

30-39 40-49 50-59 60-69 70-79 80-89

2%16%

28%

60%

67%

44%

Without onset Onset

In patients with type 2 later onset Fabry disease, onset of left ventricular hypertrophy (LVH) increased in (A) men and (B) women with the IVS4þ919G>A mutation as

they aged. % ¼ percentage of disease onset for each age group.

J A C C V O L . 6 8 , N O . 2 3 , 2 0 1 6 Hsu et al.D E C E M B E R 1 3 , 2 0 1 6 : 2 5 5 4 – 6 3 Cardiac Fibrosis Without Hypertrophy in Fabry Disease

2557

For type 1 female heterozygotes, 9 of 17 (52.9%) hadLVH and 3 (33.3%) had LGE. The other 8 female pa-tients had neither LVH nor LGE. In the type 2 renalphenotype, 1 man and 1 woman had both LVH andLGE.

We identified a total of 22 adult patients with FDwho had LGE but no LVH. Of these 22 patients, 12(9 men) underwent coronary angiography (Table 2).Among these 12 patients, 2 (Patients #9 and #19) hadboth coronary stenosis and LGE distribution in thecorresponding territory. Two patients (#17 and #20)had positive angiographic findings but LGE did notdistribute in the corresponding vascular territory. Theremaining 8 patients had negative coronary angiog-raphy. Of the other 10 patients who did not undergocoronary angiography, only 1 58-year-old man (#10)had an LGE pattern characteristic of CAD. However,all the patients with an LGE pattern of coronary dis-tribution underwent cardiac biopsy, which revealedsignificant Gb3 accumulation in their cardiomyocytes.This finding indicated that most of the LGE in thesepatients was not caused by CAD.

Seventeen IVS4 individuals who had myocardialfibrosis without LVH underwent endomyocardial bi-opsies and all had significant pathological changesand Gb3 accumulation in their cardiomyocytes. Therelationship between LVMI and LGE in male and fe-male type 2 IVS4 patients is shown in Figure 2. Threecases with representative LGE on GE-CMR and his-topathologic changes are shown in Figure 3. The

demographic data, LV function, ECG, and clinicalmanifestations of the patients with cardiac fibrosiswithout LVH are presented in Table 2.

DISCUSSION

Our newborn screening program found that the inci-dence of the type 2 later onset GLA mutation,IVS4þ919G>A, was unusually high in the TaiwanChinese population. The IVS4 mutation also wasidentified in Kagoshima, Japan (25), and in patientswith HCM in Mainland China, Singapore, Malaysia,and Vietnam (26). On the basis of Chinese migrations,the IVS4 mutation may be prevalent in southeastChina and Southeast Asia. Newborn screening inEurope and the United States revealed an incidence ofthe type 2 phenotype that was greater than those ofthe respective population’s type 1 classic phenotype(6–12). These findings indicate that the type 2phenotype may be an important hidden health issuein certain ethnic or demographic populations in theworld.

However, the natural course of the type 2 lateronset phenotype remains largely unknown, particu-larly due to its misdiagnosis as common varieties ofheart or renal disease. In Taiwan, we have identified>1,200 individuals with the IVS4 mutation, providingthe opportunity to investigate the natural course ofthese later onset patients who have a single causativemutation by cross-section analysis within a single

TABLE 2 Characteristics and Clinical Manifestations of Patients With Cardiac Fibrosis Without Cardiac Hypertrophy

Patient # Fabry Type Sex Biopsy Age (yrs) LVMI (g/m2.7) ECG/Holter Study EF (%) PW (mm) IVS (mm) Symptoms Comorbidity

1 IVS4 919G>A M Pos* 38 22.6 Normal 67 11 7.2 None None

2 IVS4 919G>A M ND 39 24.0 CRBBB 46 6 8 None None

3 IVS4 919G>A M Pos 49 32.4 Short PR interval 79 8 10.6 None HTN, HPL

4 IVS4 919G>A M Pos 49 34.5 APC and VPC 56 8 11.8 Chest tightness* HTN, chronic hepatitis,cryptorchidism

5 IVS4 919G>A M Pos* 58 36.1 RBBB 66 9 8 None HTN, HPL, gout

6 IVS4 919G>A M ND 60 45.2 Normal 82 9.5 8.2 DOE† HTN, DM, HPL

7 IVS4 919G>A M Pos* 61 35.2 T-wave inversion 76 8 10.2 Chest tightness* None

8 IVS4 919G>A M Pos* 61 40.9 IVCD 80 9 8 Chest pain† Benign prostatichyperplasia,bladder cancer

9 IVS4 919G>A M Pos*‡ 61 46.2 LAFB 72 10 9.2 None HPL, chronic hepatitis,renal stone

10 IVS4 919G>A M ND 62 40.0 T-wave inversion 75 9 11 Chest tightness* HTN

11 IVS4 919G>A M Pos* 63 40.5 SSS, APC 53 8 10.2 None None

12 IVS4 919G>A M Pos 63 43.4 Normal 78 8.6 8.6 Chest pain CAD, DM, HTN, bladdertumor osteoarthritis

13 IVS4 919G>A M Pos* 63 47.7 Short PR interval 62 10 12 DOE† None

14 IVS4 919G>A M Pos 64 40.8 IVCD, atypical LBBB 66 10 9.8 None HTN, depression

15 c.1194delA M ND 64 37.8 Sinus bradycardia 61 10 9.9 DOE† None

16 IVS4 919G>A M Pos* 65 44.6 AV block, RBBB, LAFB 76 10.2 11.3 DOE HTN, minor stroke

17 IVS4 919G>A M Pos*‡ 66 45.6 Sinus bradycardia, APC,and VPC

70 11 10 None HTN, HPL, gout

18 IVS4 919G>A F Pos 58 31.6 Atrioventricular block 79 7 6 DOE Trigeminal neuralgia,ESRD, gout

19 IVS4 919G>A F Pos*‡ 60 33.0 Sinus bradycardia 72 8.1 8.7 Chest pain CAD

20 IVS4 919G>A F Pos*‡ 62 32.5 Sinus bradycardia, T-waveinversion

66 10 9.5 None HTN, DM

21 IVS4 919G>A F ND 63 34 T-wave inversion 69 10 7.8 None None

22 IVS4 919G>A F Pos* 64 22.6 Normal 73 9 10 None None

*Received coronary angiography. †Subclinical symptom. ‡Positive for coronary stenosis.

APC ¼ atrial premature contraction; AV ¼ atrioventricular; CAD ¼ coronary artery disease; CRBBB ¼ complete right bundle branch block; DM ¼ diabetes mellitus; DOE ¼ dyspnea on exertion;ECG ¼ electrocardiogram; EF ¼ ejection fraction; ESRD ¼ end-stage renal disease; F ¼ female; HPL ¼ hyperlipidemia; HTN ¼ hypertension; IVCD ¼ intraventricular conduction delay; IVS ¼ intraventricularseptum thickness; LAFB ¼ left anterior fascicular block; LBBB ¼ left bundle branch block; LVMI ¼ left ventricular mass index; M ¼ male; ND ¼ not determined; Pos ¼ positive for globotriaosylceramideaccumulation; PW ¼ posterior wall thickness; RBBB ¼ right bundle branch block; SSS ¼ sick sinus syndrome; VPC ¼ ventricular premature contraction.

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center (Central Illustration). Few IVS4 patients under40 years of age had cardiac hypertrophy or fibrosis.However, LVH was present and increased rapidlywith age in the IVS4 adults $40 years of age and thefrequency increased decade by decade (Figure 1).Because therapeutic efforts should be initiated beforeirreversible hypertrophy and/or fibrosis, we suggestinitiating close follow-up of the cardiac conditions ofthese IVS4 individuals much earlier than 40 years ofage.

The underlying mechanisms responsible for pro-gressive LVH in FD have not been fully elucidated;however, the secondary effects of the lysosomal gly-cosphingolipid deposits should play important roles.Likely secondary effects include inflammatory re-actions (27–29), circulating hypertrophy-promotingfactors (30,31), or other genetic or environmentalfactors (32). Tissue fibrosis is always considered theend result of tissue injury, inflammation, andapoptosis; it is also regarded as an irreversible event

with little therapeutic intervention available(16,17,33). Cardiac fibrosis stands as a negative cardiacprognostic factor for ERT. A previous study ofcardiac-biopsy pathology type 2 patients from ourgroup demonstrated that even though the Gb3 accu-mulation was dramatically decreased in the car-diomyocytes after long-term ERT, heart function inthese patients did not show significant improvement,primarily due to the cardiac fibrosis that was presentbefore initiation of ERT (34). Therefore, it wasstrongly recommended that ERT should best beadministrated before myocardial fibrosis develop-ment to maintain long-term myocardial morphologyand function (16).

Here, we reported that 38.1% of male and 16.7% offemale FD patients, even without LVH, had alreadydeveloped cardiac fibrosis. These findings suggestthat severe and irreversible cardiac damage can occurbefore the development of cardiac hypertrophy intype 2 patients. Recently, Niemann et al. (35)

FIGURE 2 Relationship Between LVMI and LGE

LGE N Y

LVM

I

A

Age

100.00

75.00

50.00

25.00

125.00

25.00 35.00 45.00 55.00 65.00 75.00 85.00

LVM

I

B

Age

80.00

70.00

60.00

50.00

40.00

30.00

20.00

25.00 35.00 45.00 55.00 65.00 75.00

39.0

48.0

In (A) men and (B) women with the IVS4þ919G>A mutation, 16 of 42 (38.1%) men and 5 of 30 (16.7%) women had late gadolinium

enhancement (LGE) without left ventricular hypertrophy. LGE was measured with gadolinium-enhanced cardiac magnetic resonance.

Orange ¼ LGE present; blue ¼ no LGE present. LVMI ¼ left ventricular mass index.

J A C C V O L . 6 8 , N O . 2 3 , 2 0 1 6 Hsu et al.D E C E M B E R 1 3 , 2 0 1 6 : 2 5 5 4 – 6 3 Cardiac Fibrosis Without Hypertrophy in Fabry Disease

2559

published a large CMR imaging study of 104 FD pa-tients (58 women and 46 men). Interestingly, 10(17.2%) female patients without LVH already had LGE,although LGE was not found in male patients withoutLVH. On the basis of these results, the authorsconcluded that cardiomyopathy progression in FDdiffers in men and women, and that only the womendevelop fibrosis before hypertrophy. However, ourstudy showed that a large portion of type 2 later onsetmen also developed cardiac fibrosis before LVH.Moreover, we also identified 1 type 1 classic man whohad LGE before LVH. Together, our findings sug-gested that the development of fibrosis might occurbefore LVH in both affected men and heterozygoteswith FD.

It is noteworthy thatmost (88.2%men, 60%women)of our non-LVH patients did not have significant FDcardiac manifestations, even when they already hadsignificant fibrosis and extensive Gb3 accumulation intheir cardiomyocytes. Many of them had varyingconductive abnormalities or dyspnea on exertion(Table 2), but most did not have sufficient symptomsto seek medical attention. Thus, cardiac disease in

Fabry patients can progress silently, before signi-ficant clinical symptoms occur. These findingshighlighted the importance of early diagnosis andtherapeutic intervention in all FD patients. Moreover,the late initiation of ERT limited the effectivenessof the treatment as the fibrosis may progress early inthe course of the disease.

Our findings also highlighted the importance ofnewborn screening: it provides early detection of thefuture insidious and irreversible cardiac damage thatoccurs in adult type 2 later onset patients. In contrast,type 1 classic men are typically diagnosed earlier,often in childhood or adolescence due to the charac-teristic early manifestations. These patients oftenreceive ERT before the occurrence of irreversiblecardiac damage. However, without newbornscreening, early detection of type 2 patients (e.g.,IVS4) would be difficult, as they usually present latewith advanced cardiac or renal manifestations.

Our findings further emphasized the importance ofearly intervention for type 2 patients with cardiacdisease. Currently, many patients already have HCMand its related manifestations. Clearly, biomarkers of

FIGURE 3 Representative LGE on GE-CMR and Histopathologic Findings

Three examples show IVS4þ919G>A patients with cardiac fibrosis, but without cardiac hypertrophy: Case 1, a 60-year-old man with a normal LVMI of 45.2 g/m2.7;

Case 2, a 58-year-old man with an LVMI of 36.1 g/m2.7; and Case 3, a 38-year-old man with a LVMI of 22.6 g/m2.7. Images with LGE are shown as short-axis and

4-chamber views; arrows indicate fibrosis. The end-diastolic phase demonstrated that there was no evidence of left ventricular hypertrophy for these 3 patients.

Endomyocardial biopsies showed diffuse vacuolization on hematoxylin and eosin (HE) staining and abundant membrane-bound lamellar myelin bodies (“zebra” or

“onion-skin” appearance) on electron microscope. GE-CMR ¼ gadolinium-enhanced cardiac magnetic resonance; LGE ¼ late gadolinium enhancement.

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early cardiac disease are needed to guide initiation ofERT in type 2 patients with cardiac disease. Our resultsalso suggested that current echocardiography, routineECG, or even GE-CMR is not sensitive enough to detectthe early cardiac damage in type 2 patients. Recentstudies have shown that T1-mapping CMR imaging andstrain echocardiography might be more sensitiveto detect early cardiac manifestations (36,37).

Therefore, in Taiwan, we suggest that adult patientswith the IVS4 mutation should be carefully monitoredby performing strain echocardiography annuallyand T1-mapping CMR every 2 to 3 years, particularly inmen >30 years of age and women >40 years of age. Ifthese methods provide any abnormal results, cardiacbiopsy should be performed. After the detection ofsignificant GB3 accumulation in cardiac biopsy, ERT

CENTRAL ILLUSTRATION Fabry Disease: Newborn Screening, Disease Progression,and Recommendations

Recommendations for adult patientswith the IVS4 mutation:

Disease progression for thosewith the IVS4 mutation:

Carefully monitor with:Strain echocardiography annuallyT1-mapping CMR every 2–3 years

Newborn screening for Fabry Disease (FD) Provides early detection of the future insidious and irreversible cardiac damage

Identify Type 2 later-onset FD through IVS4 mutation

Cardiac biopsy if abnormal results

Age ≤40 yearsOnly 2%-3% show symptoms

(left ventricular hypertrophy [LVH])

Age >40 years32% females and 67% males

develop LVH

Develop severe cardiac diseasein the fourth to seventh

decades of life

If substantial Gb3 accumulationfound, start enzyme replacement

manifestations occur

Hsu, T.-R. et al. J Am Coll Cardiol. 2016;68(23):2554–63.

The large-scale newborn screening program of Fabry disease in Taiwan revealed unusually frequent disease and provided guidance for patients

with the IVS4þ919G>A (IVS4) mutation. Although patients <40 years of age rarely showed symptoms, left ventricular hypertrophy (LVH)

developed in approximately one-third of women and two-thirds of men with the mutation, leading to severe cardiac disease in later life. For

adult patients with the IVS4 mutation, regular monitoring, including annual strain echocardiography and periodic cardiac magnetic resonance

(CMR) imaging, is warranted. Significant globotriaosylceramide (Gb3) should be treated with enzyme replacement therapy.

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should be initiated before the occurrence of significantcardiac manifestations. Although earlier therapy iswarranted for improved outcomes in patients with FD,no data indicating that early treatment can preventfibrosis have been provided. Therefore, this conceptshould be further investigated, especially in our IVS4patient group.

STUDY LIMITATIONS. During the family study of theIVS4 newborns, not all grandparents were willing tocome to our hospital for confirmatory diagnosis. It ispossible that the grandparents who had some mani-festations of heart disease were more willing to comefor confirmatory diagnoses than those who did not.Therefore, there might have been a bias in regard tooverestimation of LVH prevalence of IVS4 adults inthis study.

CONCLUSIONS

The cardiac damage experienced by FD patients canprogress in silence even when severe and irreversiblecardiac damage has occurred. This may mean thatwhen significant clinical symptoms and signs of car-diac involvement have occurred, it may already betoo late to treat FD patients.

REPRINT REQUESTS AND CORRESPONDENCE: Dr.Dau-Ming Niu, Department of Pediatrics, Taipei Vet-erans General Hospital, No. 201, Section 2, Shih-PaiRoad, Taipei 112, Taiwan. E-mail: dmniu1111@yahoo.com.tw. OR Dr. Robert J. Desnick, Department ofGenetics & Genomic Sciences, Icahn School of Medi-cine at Mount Sinai, 1 Gustave L. Levy Place, New York,New York 10029. E-mail: robert.desnick@mssm.edu.

PERSPECTIVES

COMPETENCY IN PATIENT CARE AND

PROCEDURAL SKILLS: Cardiac damage in patients

with FD can progress without overt clinical manifesta-

tions even after irreversible cardiac damage has appeared.

TRANSLATIONAL OUTLOOK: Additional investigation

is needed to define criteria that facilitate earlier detection

of cardiac involvement in patients with FD and determine

the optimal timing of ERT.

Hsu et al. J A C C V O L . 6 8 , N O . 2 3 , 2 0 1 6

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KEY WORDS cardiac fibrosis,IVS4þ919G>A, late gadoliniumenhancement, newborn screening