Analysis of Cardiovascular Phenotype and
Genotype-Phenotype Correlation in Individuals With a
JAG1 Mutation and/or Alagille Syndrome
Doff B. McElhinney, MD; Ian D. Krantz, MD; Lynn Bason, MS; David A. Piccoli, MD;
Karan M. Emerick, MD; Nancy B. Spinner, PhD; Elizabeth Goldmuntz, MD
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Background—Cardiovascular anomalies are among the most common features of Alagille syndrome (AGS). Mutations of
JAG1 are found in most individuals with AGS. This study was undertaken to determine the spectrum of cardiovascular
phenotypes associated with a JAG1 mutation and/or AGS, investigate potential genotype-phenotype correlations, and
begin to correlate clinical outcome with genetic pathogenesis.
Methods and Results—We reviewed the records of 200 individuals with a JAG1 mutation or AGS. A total of 187 (94%)
subjects had evidence of cardiovascular involvement. Cardiovascular anomalies were identified by imaging in 150
subjects (75%), and 37 (19%) had a peripheral pulmonary stenosis murmur with either a normal echocardiogram or no
imaging study. Of the 150 subjects with anomalies confirmed by imaging, right-sided anomalies were present in 123 and
left-sided anomalies in 22, with both in 12. Seventeen subjects had other anomalies. The most common abnormality was
stenosis/hypoplasia of the branch pulmonary arteries (PAs), which was documented by imaging (n⫽111) or inferred
from a peripheral pulmonary stenosis murmur (n⫽41) in 76% of subjects. Tetralogy of Fallot was present in 23 subjects
and was accompanied by pulmonary atresia in 8. Branch PA phenotype differed between individuals with and without
a JAG1 mutation. Among subjects with a JAG1 mutation, there was no correlation between the type or location of
mutation and the frequency or type of cardiovascular anomaly.
Conclusions—More than 90% of individuals with a JAG1 mutation or AGS have cardiovascular anomalies, with branch
PA stenosis the most common abnormality. Cardiovascular phenotype does not correlate with the type or location of
JAG1 mutation. (Circulation. 2002;106:2567-2574.)
Key Words: cardiovascular disease 䡲 genetics 䡲 tetralogy of Fallot
A
lagille syndrome (AGS) is characterized by a constellation of phenotypic features that includes a paucity of
interlobular bile ducts, cholestasis, cardiovascular anomalies,
vertebral anomalies (typically butterfly vertebrae), ocular
anomalies (predominantly anterior chamber defects and retinal pigmentary abnormalities), and a characteristic facies
(consisting of a triangular face and chin, with a prominent
forehead, deep-set eyes, hypertelorism, flat midface, and
straight long nose).1,2 Mutations or deletions of the JAG1
gene, which encodes a ligand in the Notch signaling pathway,
have been identified in 60% to 75% of individuals with
AGS.3–5 JAG1 mutations have also been discovered in individuals with only one or two features of AGS and in relatives
of individuals with AGS who themselves have few or no
overt phenotypic manifestations of AGS.6 – 8 There does not
seem to be any correlation between the type or location of
JAG1 abnormality and phenotypic penetrance or severity.5
Congenital heart disease is one of the diagnostic criteria for
AGS.1 In previously published series, documented cardiovascular anomalies or a murmur consistent with stenosis/hypoplasia of the branch pulmonary arteries (PAs) have been
identified in 85% to 97% of individuals with AGS.1,2,9
Nonetheless, the spectrum of cardiovascular phenotypes associated with AGS is not well characterized, particularly
given that a low percentage of previous study subjects had
undergone imaging studies.10
More than 200 individuals have been screened for mutations in the JAG1 gene as part of an ongoing study at The
Children’s Hospital of Philadelphia to characterize the molecular basis of AGS. To define precisely the spectrum of
cardiovascular phenotypes in individuals with a JAG1 mutation or AGS, to ascertain whether a genotype-phenotype
correlation exists with regard to cardiovascular anatomy, and
to begin to correlate clinical outcome with genetic pathogen-
Received May 30, 2002; revision received August 23, 2002; accepted August 24, 2002.
From the Divisions of Cardiology (D.B.E., E.G.), Human Genetics (I.D.K., L.B., N.B.S.), and Gastroenterology and Nutrition (D.A.P.), The Children’s
Hospital of Philadelphia and University of Pennsylvania School of Medicine, Philadelphia, Pa, and Division of Gastroenterology (K.M.E.), Children’s
Memorial Hospital, Chicago, Ill. Dr McElhinney is now at the Department of Cardiology, Children’s Hospital, Boston, Mass.
Correspondence to Elizabeth Goldmuntz, MD, Division of Cardiology, The Children’s Hospital of Philadelphia, Abramson Research Center 702A,
3516 Civic Center Blvd, Philadelphia, PA 19104-4318. E-mail [email protected]
© 2002 American Heart Association, Inc.
Circulation is available at http://www.circulationaha.org
DOI: 10.1161/01.CIR.0000037221.45902.69
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November 12, 2002
TABLE 1. Primary Cardiovascular Anomalies Among 200 Subjects With a JAG1 Mutation
and/or AGS
Primary Cardiovascular Anomaly
Total (%)
(n⫽200)
JAG1
Mutation (%)
(n⫽154)
AGS Without a JAG1
Mutation (%)
(n⫽46)
Cardiovascular anomalies as defined by imaging modalities
150 (75)
119 (77)
31 (67)
Right-sided anomalies
110 (55)
93 (60)
17 (37)
Tetralogy of Fallot
23 (12)
20 (13)
3 (7)
Valvar pulmonary stenosis
15 (8)
11 (7)
4 (9)
Branch PA stenosis
70 (35)
60 (39)
10 (22)
Pulmonary atresia, intact ventricular septum
1 (1)
1 (1)
0 (0)
Truncus arteriosus
1 (1)
1 (1)
0 (0)
Left-sided anomalies
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13 (7)
9 (6)
4 (9)
Valvar AS
4 (2)
4 (3)
0 (0)
Bileaflet aortic valve without stenosis
2 (1)
1 (1)
1 (2)
Supravalvar AS
2 (1)
1 (1)
1 (2)
Coarctation of the aorta
4 (2)
2 (1)
2 (4)
Sinus of Valsalva aneurysm
1 (1)
1 (1)
0 (0)
27 (14)
17 (10)
10 (22)
Ventricular septal defect
10 (5)
6 (4)
4 (9)
Atrial septal defect
3 (7)
Other anomalies
10 (5)
7 (5)
Unbalanced atrioventricular septal defect
1 (1)
0 (0)
1 (2)
Patent ductus arteriosus
2 (1)
1 (1)
1 (2)
Left SVC, absent right SVC
1 (1)
1 (1)
0 (0)
Right aortic arch
1 (1)
1 (1)
0 (0)
Anomalous left coronary artery from the PA
1 (1)
1 (1)
0 (0)
Pulmonary vein stenosis
1 (1)
0 (0)
1 (2)
50 (25)
35 (23)
15 (33)
Normal or no cardiovascular imaging
PPS murmur without documented anomalies
37 (19)
27 (18)
10 (22)
Normal echocardiogram
26 (13)
19 (12)
7 (15)
No cardiovascular imaging
11 (6)
8 (5)
3 (7)
13 (7)
8 (5)
5 (11)
No PPS murmur with normal or no imaging
esis, we analyzed the cardiovascular features in the segment
of this cohort who had a defined mutation in the JAG1 gene
or had no identifiable mutation but met the clinical criteria, as
specified below, for the diagnosis of AGS.
Methods
Subjects
Subjects were drawn from a database of individuals enrolled in an
ongoing program at The Children’s Hospital of Philadelphia on the
genetic pathogenesis of AGS; some have been included in previous
publications.2,3,5,6,8,11 The program’s database includes individuals
with suspected AGS and relatives of probands who were enrolled
after the detection of a JAG1 mutation in the proband. Subjects were
considered for inclusion in the present analysis if they had been
tested for JAG1 mutations as previously described.3,8 They were
included if either a JAG1 mutation was identified or if they met the
clinical criteria for AGS (defined below). Written informed consent
was obtained for all subjects according to a protocol approved by the
Institutional Review Board for the Protection of Human Subjects at
The Children’s Hospital of Philadelphia.
Cardiovascular Phenotype and Definitions
Cardiovascular phenotype was ascertained by authors of this study
(D.B.M. and E.G.) on review of the following records, when
applicable: notes and letters from the consulting cardiologist, ECG
reports, echocardiogram reports, cardiac catheterization reports,
operative notes, and autopsy summaries. Cardiovascular anomalies
were ascertained either by physical examination reported by a
cardiologist or by additional imaging studies.
Cardiovascular phenotype was stratified according to primary and
secondary anomalies. In subjects with multiple anomalies, the
primary anomaly was considered to be that for which intervention
was performed or was most likely to be performed. In subjects with
a cardiovascular complex, such as tetralogy of Fallot (TOF), the
typical components of the complex were not listed separately as
primary and secondary anomalies. Cardiovascular anomalies were
also categorized as right-sided, left-sided, or neither right- nor
left-sided (“other”), as summarized in Table 1.
Branch PA stenosis/hypoplasia (the terms stenosis and hypoplasia
are used without specific differentiation) was defined as one or more
of the following: a documented pressure gradient ⱖ10 mm Hg by
cardiac catheterization, a gradient estimated at ⱖ15 mm Hg by
Doppler echocardiography using the simplified Bernoulli equation
(Pressure⫽4⫻velocity2), obvious stenosis/hypoplasia of one or both
branch PAs visualized by cross-sectional echocardiography or angiocardiography, or surgical or transcatheter intervention on the
branch PAs. Branch PA anomalies were characterized according to
extent (ie, discrete, diffuse, or discontinuous), severity (ie, mild or
moderate to severe), and sidedness (ie, unilateral or bilateral) of the
stenosis. Discrete PA stenosis was defined as no more than 2
McElhinney et al
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documented stenoses in the branch PA supplying either lung,
whereas diffuse PA stenosis/hypoplasia was defined as extensive
hypoplasia of the PA tree or bilateral multilevel stenosis/hypoplasia
observed on angiography. Branch PA stenosis was classified as
moderate to severe (single category) if the pressure gradient into at
least one branch PA was ⱖ30 mm Hg, a qualitative interpretation by
the cardiologist performing the diagnostic procedure was recorded as
moderate or severe stenosis/hypoplasia and a documented pressure
gradient was not available, or intervention was performed on one or
both branch PAs. Otherwise, the stenosis was considered mild. To be
considered bilateral PA stenosis, both branch PAs had to meet the
criteria for stenosis, defined above.
For the purposes of this study, the term peripheral pulmonary
stenosis (PPS) referred to the presence of a PPS murmur without
documented branch PA stenosis by imaging. If a typical PPS murmur
(systolic ejection murmur audible over the precordium with radiation
into the axillae or back) was noted on examination, the phenotype
was defined according to echocardiographic or angiographic findings, as summarized above. If a PPS murmur was noted by a
cardiologist, but no abnormalities were seen on imaging or no
imaging studies were performed, the phenotype was categorized as
“PPS murmur, normal imaging” or “PPS murmur, no imaging,”
respectively.
The gradations of severity for other obstructive anomalies (eg,
valvar pulmonary or aortic stenosis) are defined in the appropriate
table or section of the Results.
JAG1 Mutation Analysis
Analysis of JAG1 genotype was performed in all subjects, as
described previously.3,8 Subjects were initially screened with fluorescence in situ hybridization (YACs 940d11 and 881h20 used as
probes) to identify whole-gene deletions. If fluorescence in situ
hybridization demonstrated the normal complement of 2 alleles,
single-strand conformation polymorphism electrophoresis was performed to detect intragenic mutations or deletions. In subjects with
band shifts identified on electrophoresis, the mutation was characterized by direct sequencing of the corresponding coding region and
exon-intron boundaries.
Definition of Alagille Syndrome
The criteria specified by Alagille et al1 for the diagnosis of AGS
require biopsy-proven paucity of interlobular bile ducts, along with
3 of the following 5 features: chronic cholestasis, cardiovascular
anomalies (including a PPS murmur detected by a cardiologist),
vertebral anomalies, ocular anomalies, and characteristic facies (see
the introduction). For this study, we adopted a modified definition of
AGS, such that 3 of the features specified by Alagille et al1 were
necessary to meet the criteria for AGS, with biopsy-proven paucity
of interlobular bile ducts a nonessential feature. The diagnosis of
AGS was assigned after review of records by an attending geneticist
(I.D.K.).
Data Analysis
Data are presented as the number of subjects with a particular
anatomic feature or diagnosis. The frequencies of diagnoses and
anatomic variables were compared between subjects with and
without a JAG1 mutation and, within the cohort of subjects with
branch PA anomalies, between different phenotypic variables using
nonparametric analysis (␹2 or Fisher’s exact test). Genotype-phenotype analysis was then performed within the cohort of subjects with
a JAG1 mutation, with genotypic variables including the type (whole
gene deletion, protein-truncating mutation, missense mutation,
splice-site mutation) and location of mutation. Because of the large
number of subjects for whom the parent-of-origin of the mutation
was undetermined (see below), genotype-phenotype analysis with
respect to this variable was not performed. Because of the small
number of subjects without AGS according to our definition,
comparison between subjects with and without AGS was not
performed. Results are presented as ORs with 95% CIs.
JAG1 Mutation and Cardiovascular Phenotype
2569
Results
Subjects
Documentation of cardiovascular phenotype was requested
from the referring physician or family of 222 individuals in
the aforementioned database, all of whom were tested for
JAG1 mutations. Adequate cardiac data were obtained for
200 of these individuals (90%), including 154 (77%) with a
JAG1 mutation and 188 (94%) who met our criteria for AGS.
The study cohort consisted of these 200 subjects, whereas
those with inadequate cardiovascular data were omitted from
the analysis. Among the 154 subjects with a JAG1 mutation,
142 (92%) met our criteria for AGS, 127 were probands
enrolled in the study with suspected AGS, and 27 were
relatives without previously suspected AGS (in some cases,
there were multiple probands in a single kindred).
Cardiovascular Phenotype
Of the 200 subjects in the study cohort, 196 (98%) were
evaluated by a cardiologist, whereas the other 4 were reported
to have no murmur on physical examination by at least one
physician. Echocardiography was performed in 180 (90%)
subjects, and 59 (30%) underwent both echocardiography and
cardiac catheterization, including 33% of subjects (n⫽51)
with a JAG1 mutation and 17% of subjects without (n⫽8).
Of the 200 subjects with adequate cardiac data, 187 (94%)
had some form of cardiovascular involvement. A wide variety
of cardiovascular anomalies were diagnosed by imaging in
150 (75%) subjects, and distal branch PA anomalies were
suspected in 37 (19%) subjects who had a PPS murmur with
either a normal echocardiogram or no imaging studies. Of the
150 subjects with anomalies documented by imaging, 105
had a single anomaly and 45 had multiple anomalies. Tables
1 and 2 list the primary and secondary cardiovascular
diagnoses, respectively. Right-sided anomalies were documented in 123 subjects (62% of 200) and left-sided anomalies
were documented in 22 (11% of 200), 12 of whom had both
right- and left-sided anomalies. Among the 150 subjects with
documented cardiovascular abnormalities, right ventricular
hypertrophy was diagnosed by electrocardiography or cardiac
imaging in 69 (35%). No primary arrhythmias were noted on
review of electrocardiograms.
Among the 50 subjects with either normal or no imaging
studies, 37 (19% of 200) had a PPS murmur and either a
normal echocardiogram (n⫽26) or no cardiac imaging
(n⫽11). Of the 26 subjects with a PPS murmur but a normal
echocardiogram, 2 had electrocardiographic features of right
ventricular hypertrophy. The remaining 13 (7% of 200)
subjects did not have a murmur and had either a normal
echocardiogram (n⫽4) or no imaging study (n⫽9).
Abnormalities of the branch PAs were identified by imaging in 111 subjects (56%). Murmurs suggesting branch PA
anomalies without documented stenosis/hypoplasia on imaging studies were heard by a cardiologist in 41 additional
subjects (20%), including 4 with and 37 without other
cardiovascular anomalies (Table 3). Of the 111 subjects with
branch PA anomalies detected by imaging, 55 (50%) had
isolated anomalies of the branch PAs and 56 (50%) had
associated cardiovascular malformations (including TOF).
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November 12, 2002
TABLE 2. Secondary Diagnoses Among 45 Subjects With
Multiple Cardiovascular Anomalies
Secondary Cardiovascular Anomaly
Right-sided anomalies
Valvar pulmonary stenosis*
Branch PA stenosis*
Double-chambered right ventricle
Genotype-Phenotype Analysis
JAG1
AGS Without a
Total Mutation JAG1 Mutation
(n⫽45) (n⫽32)
(n⫽13)
21
11
4
0
10
4
16
10
6
0
1
1
12
10
2
Valvar AS
8
6
2
Bileaflet aortic valve without stenosis
2
2
0
0
Left-sided anomalies
Supravalvar AS
2
2
25
20
5
Ventricular septal defect*
6
5
1
Atrial septal defect
6
5
1
Other anomalies
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Patent ductus arteriosus*
9
6
3
Left SVC, absent right SVC
3
3
0
Left SVC, normal right SVC
8
7
1
Biventricular fibrosis/calcification†
1
1
0
Because some subjects had multiple secondary anomalies within a category
(ie, right-sided, left-sided, other), the sums of subcategories (eg, “other
anomalies”) do not necessarily equal the total number of subjects listed in the
category. Moreover, because some subjects had primary and secondary
diagnoses in the same category (eg, 2 left-sided anomalies), the sum of
subjects listed under a category in Tables 1 and 2 may not equal the total
number of subjects with anomalies in that category.
*Values do not include subjects with TOF or truncus arteriosus, in whom
these anomalies are either a component of the primary lesion or frequently
present.
†Diagnosed at autopsy.
Subjects with associated cardiovascular malformations
were significantly more likely to have severe PA stenosis
(OR 3.1 [95% CI, 1.4 to 7.0], P⫽0.006) and bilateral PA
stenosis (OR 1.2 [95% CI, 1.0 to 1.4], P⫽0.05) than those
without. Both of these differences were heavily influenced
by the number of subjects with TOF and were no longer
significant when subjects with TOF were excluded from
the analysis.
Twenty-three (12%) of our subjects had TOF, phenotypic
details of which are described in Table 4. The pulmonary
valve was stenotic in 14 subjects, atretic in 8, and absent in 1.
The aortic arch was left-sided in those for whom aortic arch
anatomy was specified, of which 2 had an aberrant right
subclavian artery. An additional 20 (10%) individuals (without TOF) had abnormalities of the pulmonary valve, as
detailed in Table 5. In this subset, the pulmonary valve was
stenotic in 19 subjects and atretic with an intact ventricular
septum in 1.
Left-sided cardiovascular anomalies were present in 22
subjects and were associated with additional cardiac defects
in 13, as summarized in Table 6. Valvar and supravalvar
aortic anomalies as well as coarctation of the aorta were
identified. Details of subjects with other intracardiac anomalies, including atrial and ventricular septal detects, are
summarized in Table 7.
Mutations or deletions of JAG1 were present in 154 (77%)
subjects, including 12 with a deletion of the entire gene, 104
with an intragenic frameshift mutation, 24 with an intragenic
missense mutation, and 14 with a splice-site consensus
sequence alteration. Mutations were de novo in 46 subjects,
maternally inherited in 21, paternally inherited in 19, and
undetermined in 64.
Individuals with a JAG1 mutation had a significantly
higher frequency of branch PA anomalies (OR 2.1 [95% CI,
1.1 to 4.0], P⫽0.03), bilateral branch PA anomalies (OR 2.2
[95% CI, 1.1 to 4.5], P⫽0.02), and diffuse stenosis/hypoplasia of the PAs (OR 12.5 [95% CI, 1.7 to 94], P⫽0.001) than
individuals with AGS but no JAG1 mutation. None of the
other anatomic variables differed according to the presence or
absence of a JAG1 mutation.
Among the 154 subjects with a JAG1 mutation, there was
no correlation between the type or location of the JAG1
mutation and the frequency or type of cardiovascular malformation. In fact, there was considerable variability in cardiovascular phenotype among subjects with JAG1 mutations of
all types and locations and even among probands and affected
parents and siblings with identical mutations.
There were 12 subjects with a JAG1 mutation who did not
meet our criteria for AGS. All except 1 of these subjects were
evaluated for a JAG1 mutation after identification of a
mutation in a child or sibling with AGS. Cardiovascular
anomalies were documented in 3 of these subjects (bilateral
branch PA stenosis in 2 and a sinus of Valsalva aneurysm in
1) and suspected on the basis of a PPS murmur in 3, 2 of
whom had a normal echocardiogram. The remaining 6
subjects without AGS had a normal cardiac physical examination, of which 2 had a normal echocardiogram.
Clinical Outcome
Cross-sectional cardiovascular follow-up data were available
for 148 subjects (74%) at an average of 8.3⫾9.2 years after
the earliest documentation of cardiovascular evaluation that
we were able to obtain. At least 1 cardiovascular intervention
was performed in 23% (n⫽46) of subjects, including 23%
(n⫽36) of those with a JAG1 mutation and 22% (n⫽10) of
those without. During follow-up, 14 (7%) subjects (12 with
and 2 without a JAG1 mutation) were reported to have died
from cardiovascular causes, including 10 with TOF (43% of
subjects with TOF), 2 with isolated severe branch PA
stenosis, 1 with truncus arteriosus, and 1 with a sinus of
Valsalva aneurysm. Of the 10 subjects with TOF who died of
cardiovascular causes, 6 had TOF and pulmonary atresia
(75% of 8), 3 had TOF and pulmonary stenosis (21% of 14),
and 1 had TOF and absent pulmonary valve.
Among subjects with branch PA stenosis (not including
those with TOF), serial echocardiographic data were available in 55. The follow-up echocardiograms did not demonstrate significant progression of the branch PA stenosis in any
subject; 5 subjects (4 with severe stenosis initially and 1 with
mild stenosis) had small decreases (10 to 15 mm Hg) in the
severity of branch PA obstruction, and 1 with mild stenosis
initially had a small increase in the severity of obstruction.
McElhinney et al
TABLE 3.
JAG1 Mutation and Cardiovascular Phenotype
2571
Branch PA Anatomy in Study Cohort
Anatomic Feature
Total (%)
(n⫽200)
JAG1
Mutation (%)
(n⫽154)
AGS Without a JAG1
Mutation (%)
(n⫽46)
Branch PA anomalies identified by imaging
111 (56)
91 (59)
20 (43)
55 (50)
47 (52)
8 (40)
Discrete
46 (84)
38 (81)
8 (100)
Diffuse
9 (16)
9 (19)
0 (0)
Discontinuous branch PAs
0 (0)
0 (0)
0 (0)
Isolated PA anomalies
Extent of PA stenosis/hypoplasia
Severity of PA stenosis/hypoplasia
Mild
27 (49)
24 (51)
3 (37)
Moderate to severe
28 (51)
23 (49)
5 (63)
Bilateral
44 (80)
38 (81)
6 (75)
Unilateral
11 (20)
9 (19)
2 (25)
10 (91)
8 (89)
2 (100)
Sidedness of PA stenosis/hypoplasia
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Left PA stenosis only
Right PA stenosis only
1 (9)
1 (11)
0 (0)
Associated cardiovascular anomalies*
56 (50)
44 (48)
12 (60)
Discrete
28 (50)
17 (39)
11 (92)
Diffuse
24 (43)
23 (52)
1 (8)
4 (7)
4 (9)
0 (0)
Mild
13 (23)
11 (25)
2 (17)
Moderate to severe
43 (77)
33 (75)
10 (83)
Bilateral
51 (91)
42 (95)
9 (75)
Unilateral
5 (9)
2 (5)
3 (25)
Extent of PA stenosis/hypoplasia
Discontinuous branch PAs†
Severity of PA stenosis/hypoplasia
Sidedness of PA stenosis/hypoplasia
Left PA stenosis only
5 (100)
2 (100)
3 (100)
Right PA stenosis only
0 (0)
0 (0)
0 (0)
41 (21)
30 (19)
11 (24)
Branch PA anomalies suspected from PPS murmur without
documentation by imaging
Abnormal intracardiac anatomy
4
3
1
4
3
1
37
27
10
PPS murmur with normal PAs on echocardiogram
26
19
7
PPS murmur with no cardiac imaging
11
8
3
PPS murmur with normal PAs on echocardiogram
Normal intracardiac anatomy
No PPS murmur or documentation of branch PA anomalies
48 (24)
33 (21)
15 (31)
Abnormal intracardiac anatomy
35
25
10
Normal or no imaging
13
8
5
Percentages are based on the immediately preceding stratum.
*Includes subjects with TOF.
†In all subjects with discontinuous branch PAs, the distal PA tree was diffusely hypoplastic, but these individuals are not included
in the diffuse category.
Discussion
Cardiovascular Phenotype
This study analyzes the cardiovascular phenotype in 200
subjects with a JAG1 mutation or AGS. Cardiovascular
anomalies were defined by imaging in 75% of subjects. An
additional 19% of subjects had a PPS murmur on examination by a cardiologist but either had a normal echocar-
diogram or did not undergo cardiovascular imaging. If
these individuals are considered by examination to have
some degree of stenosis/hypoplasia of the PA tree that
might not be detected by routine echocardiography, then
94% of individuals studied have evidence of cardiovascular involvement. The most frequently affected segment of
the cardiovascular system was the branch PA tree, with
anomalies of the branch PAs documented by imaging
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November 12, 2002
TABLE 4.
Anatomic Features of Subjects With TOF
AGS Without
a JAG1
Mutation (%)
(n⫽3)
Total
(%)
(n⫽23)
JAG1
Mutation (%)
(n⫽20)
Stenosis
14 (61)
11 (55)
Atresia
8 (35)
8 (40)
0 (0)
Absent
1 (4)
1 (5)
0 (0)
Anatomic Feature
Pulmonary valve
3 (100)
Pulmonary blood supply*
Diffuse PA hypoplasia
15 (65)
14 (70)
1 (33)
Discontinuous branch PAs
4 (17)
4 (25)
0 (0)
MAPCAs
8 (35)
8 (40)
0 (0)
Left
16 (100)
14 (100)
Right
0 (0)
0 (0)
14 (88)
12 (86)
2 (12)
2 (14)
0 (0)
Abnormal coronary artery pattern†
2 (9)
2 (10)
0 (0)
Valvar AS
3 (13)
3 (15)
0 (0)
Aortic arch sidedness†
2 (100)
0 (0)
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Aortic arch branching pattern†
Normal
Aberrant right subclavian artery
Genotype-Phenotype Considerations
2 (100)
MAPCAs indicates major aortopulmonary collateral arteries.
*These categories are not mutually exclusive: all individuals with discontinuous branch PAs had MAPCAs and diffuse PA hypoplasia.
†Data not available for all subjects.
(n⫽111) or inferred from a PPS murmur (n⫽41) in 76% of
subjects.
There are several particularly interesting findings of this
study. First, although AGS has been considered a disease of
TABLE 5. Anatomic Features of Subjects With Anomalies of
the Pulmonary Valve*
Anatomic Feature
Valvar pulmonary atresia with intact
ventricular septum
Valvar pulmonary stenosis
Total
(n⫽20)
JAG1
Mutation
(n⫽12)
AGS Without a
JAG1 Mutation
(n⫽8)
1
1
0
19
11
8
Isolated valvar pulmonary stenosis
8
4
4
Associated with other anomalies†
11
7
4
Branch PA stenosis
7
5
2
Ventricular septal defect
5
3
2
Atrial septal defect
3
3
0
Patent ductus arteriosus
2
0
2
Coarctation of the aorta
1
0
1
Bileaflet aortic valve
1
0
1
Pulmonary vein stenosis
1
0
1
Severity of stenosis
Moderate/severe (⬎40mm Hg)
Mild (⬍40 mm Hg)
the right side of the heart, left-sided cardiovascular anomalies
were noted in 11% of our study population, including 12 (6%)
subjects with both left- and right-sided defects, an extremely
uncommon combination. Second, the frequency of severe
forms of TOF, particularly TOF with pulmonary atresia and
major aortopulmonary collateral arteries, was substantially
higher than in the general population of individuals with
TOF, where only 20% have pulmonary atresia.12 Third, all of
the individuals in this study with TOF for whom data were
available regarding the sidedness and branching pattern of the
aortic arch had a left-sided (ie, normal) aortic arch and only
2 had an abnormal aortic arch branching pattern. In contrast,
abnormal sidedness or branching of the aortic arch is common among individuals with TOF and a chromosome 22q11
deletion.13 Finally, 4 of the 200 subjects (2%) were found to
have an absent right superior vena cava, which is otherwise
extremely rare.14,15
6
4
2
13
7
6
*Does not include subjects with TOF.
†Multiple associated anomalies were present in some subjects, so the
number of individual associated lesions do not sum to the number of subjects
with associated anomalies.
Of the 200 subjects in this study, a JAG1 mutation was
identified in 154 (77%), which is similar to the 60% to 75%
frequency reported in other studies of JAG1 mutations in
individuals with AGS.5 We have hypothesized that the
identification of JAG1 mutations in only 60% to 75% of
individuals with AGS is attributable to technical limitations
of the testing methods presently used rather than a separate
pathogenesis for AGS in individuals without an identified
JAG1 mutation.5 Of note, however, is that there were small
but significant differences in the PA phenotype between
subjects with and without a JAG1 mutation, raising the
possibility that AGS is attributable to mutations in JAG1
functional domains outside of the open-reading frame or to
different genetic mechanisms in at least some individuals
without an identified JAG1 mutation. Correlation of these
cardiac findings with other features of AGS, as well as
additional molecular analysis, will be required to clarify this
issue.
Within the cohort of subjects with a JAG1 mutation, there
was no correlation between the type or location of the JAG1
mutation and the presence or type of cardiovascular anomaly.
This finding is not surprising, given that cardiovascular status
can vary markedly between family members sharing the same
mutation.5 Moreover, most mutations are predicted to result
in loss of protein function.5,16 The variable phenotypic expression of a JAG1 mutation in the cardiovascular system
suggests that additional epigenetic factors or genetic background influence the final cardiac phenotype.
Clinical Implications
Although details of cardiovascular clinical outcome were
only available for 74% of the study cohort, our analysis
reveals several important findings. Among 23 subjects with
TOF, 10 (43%) were known to have died from cardiovascular
causes, including 6 of 8 with TOF and pulmonary atresia. The
apparently poor outcome among individuals with a JAG1
mutation and TOF with pulmonary atresia is striking and
warrants additional investigation, because it may have implications for clinical decision making in this subset of
individuals.
McElhinney et al
TABLE 6.
JAG1 Mutation and Cardiovascular Phenotype
2573
Anatomic Features of Subjects With Left-Sided Cardiovascular Anomalies
Anatomic Feature
Isolated left-sided anomalies
Left-sided anomalies with associated anomalies
Total
(n⫽22)
JAG1 Mutation
(n⫽17)
AGS Without a
JAG1 Mutation
(n⫽5)
9
7
1
13
10
4
Associated left-sided anomalies*
3
2
1
Associated right-sided anomalies*
11
9
3
Associated septal anomalies only
1
1
0
Specific anomalies
Valvar AS
12
10
2
Mild stenosis†
9
7
2
Moderate-severe stenosis†
3
3
0
Isolated valvar AS
4
4
0
Valvar AS associated with other anomalies
8
6
2
4
3
1
1
1
0
Supravalvar AS‡
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Isolated supravalvar AS
Supravalvar AS associated with other anomalies
3
2
1
4
2
2
Isolated coarctation of the aorta
1
1
0
Coarctation of the aorta associated with other anomalies
3
1
2
Coarctation of the aorta
Bileaflet aortic valve without stenosis
4
3
1
Isolated bileaflet aortic valve
2
1
1
Bileaflet aortic valve associated with other anomalies
2
2
0
*Two subjects had both left- and right-sided associated anomalies. Associated right-sided anomalies included TOF
(n⫽3), branch PA stenosis (n⫽8), and valvar pulmonary stenosis (n⫽2, both with branch PA stenosis as well).
†All subjects with mild valvar AS had pressure gradients ⱕ25 mm Hg, and all subjects with moderate-severe valvar
AS had pressure gradients ⱖ50 mm Hg.
‡All subjects with supravalvar AS had pressure gradients ⱕ35 mm Hg.
Equally important, among 55 subjects with branch PA
stenosis (not including those with TOF) and serial imaging
studies, there were no cases in which the severity of the
branch PA stenosis increased substantially over time. There
were small changes in 10% of these subjects, which consisted
of a decrease in the stenotic gradient in all but 1 case. These
findings may be helpful in counseling and decision-making
for individuals with AGS or a JAG1 mutation and branch PA
stenosis.
Potential Biases
There does not seem to be any systematic bias regarding the
composition of our study cohort. However, it is possible that
individuals with a JAG1 mutation who have no or few
phenotypic features and have no relatives with overt AGS
may be underrepresented in our study group. A survival bias
is also possible, because individuals with severe forms of
cardiovascular disease may be underrepresented due to neonatal or early infant mortality.
One of the most significant biases affecting this study is the
limited number of subjects in whom the distal PA tree was
imaged. To definitively characterize the PA anatomy in
subjects with AGS, evaluation of the distal PA tree by
angiography or MRI would be necessary, because echocardiography only provides images of the proximal branch PAs.
Two of the subjects in our series with a PPS murmur but no
branch PA stenosis/hypoplasia by echocardiography had
electrocardiographic evidence of right ventricular hypertrophy, which suggests significant obstruction in the distal PA
tree. Only 30% of subjects in this series underwent imaging
of the distal pulmonary vascular tree, many of whom had
TOF. Thus, our characterization of PA anatomy and ascertainment of PA anomalies, especially diffuse involvement, is
incomplete, and our determination of discrete versus diffuse
PA involvement is most likely biased. From a practical point
of view, this is inevitable, because there is no clinical
indication for invasive imaging studies in most individuals
with AGS or a JAG1 mutation.
Conclusions
These findings should assist the cardiologist, hepatologist,
and pediatrician in counseling families and providing appropriate evaluation and follow-up for patients with AGS or a
JAG1 mutation. The phenotypic spectrum should remind the
cardiologist to take additional family history and be observant
for signs of AGS, especially in individuals with distal branch
PA disease. Finally, detailed examination of the cardiovascular phenotype in this cohort will allow for future studies
correlating clinical outcome with genetic pathogenesis.
Acknowledgments
This work was supported by National Institutes of Health grants P50
HL62177 (to Drs Spinner and Goldmuntz), RO1 DK53104 (to Dr
2574
Circulation
November 12, 2002
TABLE 7. Anatomic Features of Subjects With Other
Intracardiac Anomalies*
Anatomic Feature
Atrial septal defect (ASD)
information, and Raymond Colliton for his work on JAG1
genotyping.
JAG1
AGS Without a
Total Mutation JAG1 Mutation
13
9
4
Isolated ASD
4
3
1
ASD associated with other anomalies†
9
6
3
Branch PA stenosis
8
5
3
Valvar pulmonary stenosis
3
3
0
Valvar AS
2
2
0
Ventricular septal defect
2
2
0
16
11
5
6
5
1
Ventricular septal defect (VSD)
Isolated VSD
VSD associated with other anomalies†
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10
6
4
Branch PA stenosis
5
4
1
Valvar pulmonary stenosis
6
3
3
Atrial septal defect
2
2
0
Patent ductus arteriosus
3
2
1
Double-chambered right ventricle
1
1
0
Pulmonary vein stenosis
1
0
1
Perimembranous
9
5
4
Muscular
2
2
0
Subarterial (conoseptal hypoplasia)
1
0
1
Data not available
4
4
0
1
0
1
Type of VSD
Atrioventricular septal defect (unbalanced)
*Does not include subjects with TOF, pulmonary atresia with intact
ventricular septum, or truncus arteriosus.
†Multiple associated anomalies were present in some subjects, so the
numbers of individual associated lesions do not sum to the numbers of subjects
with associated anomalies.
Spinner), and KO8 DK02541 (to Dr Krantz) and a grant from The
Fred and Suzanne Biesecker Foundation and Pediatric Liver Center
(to Dr Piccoli). We would like to thank the subjects and families that
participated in this study, the referring physicians that provided
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Analysis of Cardiovascular Phenotype and Genotype-Phenotype Correlation in
Individuals With a JAG1 Mutation and/or Alagille Syndrome
Doff B. McElhinney, Ian D. Krantz, Lynn Bason, David A. Piccoli, Karan M. Emerick, Nancy
B. Spinner and Elizabeth Goldmuntz
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Circulation. 2002;106:2567-2574
doi: 10.1161/01.CIR.0000037221.45902.69
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