Reviewer’s report
Title: 
Successful Treatment of Infantile Oxysterol 7
α
-hydroxylase Deficiency
with Oral Chenodeoxycholic Acid
Version: 
0 
Date: 
27 Nov 2020
Reviewer's report:
Major Comments
Abstract and Background: "Most patients with CYP7B1 deficiency succumb to
liver failure in early life." There are more reports of SPG5 due to CYP7B1
mutations than there are reports of liver failure due to CYP7B1 mutations. So I
think this should read, "Most reported patients with CYP7B1 mutations
presenting with liver disease in infancy have died of liver failure".
Page 3 and Figure 2. Urinary bile acid profiles. Interpretation of the spectra
would have been greatly enhanced by daughter ion scans. There is a very
prominent peak in the first spectrum with mass/charge ratio 480. While this
could be 
a glycine-conjugated tetrahydroxycholanoic acid (seen frequently in
infants with liver disease and/or on ursodeoxycholic acid), it could also be
taurine-conjugated 3beta-hydroxy-5-cholenoic acid and this was the largest peak
described for the 
CYP7B1 deficient patient 
in the Dai et al. paper. In the former
case the major daughter ion would be m/z 74; in the latter case, m/z 80. Bile acid
identities could also have been clarified by GC-MS
In the interpretation of subsequent urine bile acid analyses, a peak with
mass/charge ratio 510 
is interpreted as indicating the presence of glycine- and
sulphate- conjugated 3beta-hydroxy-5-cholenoic acid, however, children with
severe liver disease often excrete taurine-conjugated 7alpha,12alpha,3-oxo-4-
cholenoic acid which also has a mass/charge ratio of 510. These two bile acids
can again be distinguished by their principal daughter ions so tandem MS
analysis (or GC-MS) would have been helpful.
"Consequently, repeat testing combined with genetic analysis is usually
recommended in cases like this to definitively confirm the diagnosis". It is also
important to point out how difficult it is to interpret spectra from children who
are being treated with ursodeoxycholic acid and wherever possible samples
should be sent for analysis at least 2 weeks after stopping this treatment.
Minor Comments
Spaces between words missing: e.g. P2 "inCYP7B1(Fig.1)"
P2 "Physical examinations showed jaundice, groan and shortness of breath". I
am not sure what the authors are attempting to say with the word "groan".
Perhaps "groaning"; 
a sick child may groan but it is not a particularly useful sign.
Perhaps "grunting"; in the first few weeks of life he/she may grunt - a sign of
expiration against a partially closed glottis that indicates respiratory distress.
Also "shortness of breath" is a subjective sign that can be described by adults; for
infants it is more usual to describe what can be objectively observed e.g.
tachypnoea, grunting, recession, cyanosis.
"The laboratory investigations showed elevated levels of … 
total bile acids
(TBA), …" It is important to state the method being used for TBA analysis. It
was probably a method based on 3alpha-hydroxysteroid dehydrogenase; this
gives a low value for many children with inborn errors of bile acid synthesis
because synthesis of 3alpha-hydroxy bile acids is reduced. 
P4. "Recent lumbar magnetic resonance imaging (MRI) suggested physiological
bending become straightening..". 
I don't know what this means; the English
requires attention.
Figure 3. Arrows indicating the features described would help readers without
expertise in brain MRI interpretation.
P4. "By contrast, the acidic pathway is initiated by 27-hydroxylation of
cholesterol followed by 7
α
-hydroxylation of the monohydroxylated
intermediates 3
β
-hydroxy-5-cholestenoic and 3
β
-hydroxy-5-cholenoic acids to
yield CDCA [2, 13, 14], a reaction that is catalyzed by oxysterol-7
α
-hydroxylase
(CYP7B1)". Suggest "By contrast, the acidic pathway is initiated by 27-
hydroxylation of cholesterol followed by 7
α
-hydroxylation of the
monohydroxylated intermediates 3
β
-hydroxy-5-cholestenoic and 3
β
-hydroxy-5-
cholenoic acids, a reaction that is catalyzed by oxysterol-7
α
-hydroxylase
(CYP7B1); this pathway leads ultimately to 
production of CDCA [2, 13, 14]"
P5. "CDCA suppressed sterol 27-hydrolylase" > 27-hydroxylase
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Please complete a declaration of competing
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1
. 
Have you in the past five years received reimbursements, fees, funding, or
salary from an organisation that may in any way gain or lose financially
from the publication of this manuscript, either now or in the future?
2
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gain or lose financially from the publication of this manuscript, either now
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3
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organization that holds or has applied for patents relating to the content of
the manuscript?
5
. 
Do you have any other financial competing interests?
6
. 
Do you have any non-financial competing interests in relation to this
paper?
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interests' below. If your reply is yes to any, please give details below.
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Reviewer Publication Consent.
 I agree for my report to be made available
under an Open Access Creative Commons CC-BY License (
http://creativecommons.org/licenses/by/4.0
) if this manuscript is accepted for
publication. Any comments that I do not wish to be included in the published
report have been included as confidential comments to the editor, which will not
be published.
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I agree to the terms of the CC-BY 4.0 license; please 
do not
 publish my name
with my report. (default)
Is the study design appropriate to answer the research question (including the use
of appropriate controls), and are the conclusions supported by the evidence
presented?
Yes
Are the methods sufficiently described to allow the study to be repeated?
Yes
Is the use of statistics and treatment of uncertainties appropriate?
Yes
Is the presentation of the work clear?
Yes
Are the images in this manuscript (including electrophoretic gels and blots) free
from apparent manipulation?
Yes
Reviewer’s report
Title: 
Successful Treatment of Infantile Oxysterol 7
α
-hydroxylase Deficiency
with Oral Chenodeoxycholic Acid
Version: 
0 
Date: 
27 Nov 2020
Reviewer's report:
Major Comments
Abstract and Background: "Most patients with CYP7B1 deficiency succumb to
liver failure in early life." There are more reports of SPG5 due to CYP7B1
mutations than there are reports of liver failure due to CYP7B1 mutations. So I
think this should read, "Most reported patients with CYP7B1 mutations
presenting with liver disease in infancy have died of liver failure".
Page 3 and Figure 2. Urinary bile acid profiles. Interpretation of the spectra
would have been greatly enhanced by daughter ion scans. There is a very
prominent peak in the first spectrum with mass/charge ratio 480. While this
could be 
a glycine-conjugated tetrahydroxycholanoic acid (seen frequently in
infants with liver disease and/or on ursodeoxycholic acid), it could also be
taurine-conjugated 3beta-hydroxy-5-cholenoic acid and this was the largest peak
described for the 
CYP7B1 deficient patient 
in the Dai et al. paper. In the former
case the major daughter ion would be m/z 74; in the latter case, m/z 80. Bile acid
identities could also have been clarified by GC-MS
In the interpretation of subsequent urine bile acid analyses, a peak with
mass/charge ratio 510 
is interpreted as indicating the presence of glycine- and
sulphate- conjugated 3beta-hydroxy-5-cholenoic acid, however, children with
severe liver disease often excrete taurine-conjugated 7alpha,12alpha,3-oxo-4-
cholenoic acid which also has a mass/charge ratio of 510. These two bile acids
can again be distinguished by their principal daughter ions so tandem MS
analysis (or GC-MS) would have been helpful.
"Consequently, repeat testing combined with genetic analysis is usually
recommended in cases like this to definitively confirm the diagnosis". It is also
important to point out how difficult it is to interpret spectra from children who
are being treated with ursodeoxycholic acid and wherever possible samples
should be sent for analysis at least 2 weeks after stopping this treatment.
Minor Comments
Spaces between words missing: e.g. P2 "inCYP7B1(Fig.1)"
P2 "Physical examinations showed jaundice, groan and shortness of breath". I
am not sure what the authors are attempting to say with the word "groan".
Perhaps "groaning"; 
a sick child may groan but it is not a particularly useful sign.
Perhaps "grunting"; in the first few weeks of life he/she may grunt - a sign of
expiration against a partially closed glottis that indicates respiratory distress.
Also "shortness of breath" is a subjective sign that can be described by adults; for
infants it is more usual to describe what can be objectively observed e.g.
tachypnoea, grunting, recession, cyanosis.
"The laboratory investigations showed elevated levels of … 
total bile acids
(TBA), …" It is important to state the method being used for TBA analysis. It
was probably a method based on 3alpha-hydroxysteroid dehydrogenase; this
gives a low value for many children with inborn errors of bile acid synthesis
because synthesis of 3alpha-hydroxy bile acids is reduced. 
P4. "Recent lumbar magnetic resonance imaging (MRI) suggested physiological
bending become straightening..". 
I don't know what this means; the English
requires attention.
Figure 3. Arrows indicating the features described would help readers without
expertise in brain MRI interpretation.
P4. "By contrast, the acidic pathway is initiated by 27-hydroxylation of
cholesterol followed by 7
α
-hydroxylation of the monohydroxylated
intermediates 3
β
-hydroxy-5-cholestenoic and 3
β
-hydroxy-5-cholenoic acids to
yield CDCA [2, 13, 14], a reaction that is catalyzed by oxysterol-7
α
-hydroxylase
(CYP7B1)". Suggest "By contrast, the acidic pathway is initiated by 27-
hydroxylation of cholesterol followed by 7
α
-hydroxylation of the
monohydroxylated intermediates 3
β
-hydroxy-5-cholestenoic and 3
β
-hydroxy-5-
cholenoic acids, a reaction that is catalyzed by oxysterol-7
α
-hydroxylase
(CYP7B1); this pathway leads ultimately to 
production of CDCA [2, 13, 14]"
P5. "CDCA suppressed sterol 27-hydrolylase" > 27-hydroxylase
Publons Reviewer Recognition
. Springer Nature can send verification of this
review directly to Publons (a subsidiary of Clarivate Analytics). If you would
like to take advantage of this service, please click on the “Yes” option below.
Your name, email address, title of the reviewed manuscript, name of the journal,
and date of your review submission (the “Review Data”) will then be transmitted
to Publons after the final decision on the manuscript has been made. If you have
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and update your profile 
as per your settings and their policy. If you are not
registered with Publons, you will receive an email from them asking you to
register in order for them to be able to recognize your review on your new
profile page. Publons may use the Review Data to generate derivative metadata
for the benefit of Publons and you as a reviewer, carefully considering the
sensitivity of such information. For example, Publons may verify your record as
a reviewer by updating your profile published on its webservice if you have
registered for such service or help editors to identify candidate reviewers. Please
find the details of processing in Publons’ privacy policy
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Yes
Declaration of competing interests
Please complete a declaration of competing
interests, considering the following questions:
1
. 
Have you in the past five years received reimbursements, fees, funding, or
salary from an organisation that may in any way gain or lose financially
from the publication of this manuscript, either now or in the future?
2
. 
Do you hold any stocks or shares in an organisation that may in any way
gain or lose financially from the publication of this manuscript, either now
or in the future?
3
. 
Do you hold or are you currently applying for any patents relating to the
content of the manuscript?
4
. 
Have you received reimbursements, fees, funding, or salary from an
organization that holds or has applied for patents relating to the content of
the manuscript?
5
. 
Do you have any other financial competing interests?
6
. 
Do you have any non-financial competing interests in relation to this
paper?
If you can answer no to all of the above, write 'I declare that I have no competing
interests' below. If your reply is yes to any, please give details below.
'I declare that I have no competing interests'
Reviewer Publication Consent.
 I agree for my report to be made available
under an Open Access Creative Commons CC-BY License (
http://creativecommons.org/licenses/by/4.0
) if this manuscript is accepted for
publication. Any comments that I do not wish to be included in the published
report have been included as confidential comments to the editor, which will not
be published.
If you are not happy for us to publish this report, please contact the
editorial office before completing the review.
If you wish, you can include your
name in your published report. Please note you must decide whether to include
your name at the start of the process and confirm this decision whenever
prompted. If you change your decision later, we will not be able to publish your
name.
I agree to the terms of the CC-BY 4.0 license; please 
do not
 publish my name
with my report. (default)
Is the study design appropriate to answer the research question (including the use
of appropriate controls), and are the conclusions supported by the evidence
presented?
Yes
Are the methods sufficiently described to allow the study to be repeated?
Yes
Is the use of statistics and treatment of uncertainties appropriate?
Yes
Is the presentation of the work clear?
Yes
Are the images in this manuscript (including electrophoretic gels and blots) free
from apparent manipulation?
Yes
Please review this paper.
user
Reviewer’s report
Title: 
Successful Treatment of Infantile Oxysterol 7
α
-hydroxylase Deficiency
with Oral Chenodeoxycholic Acid
Version: 
0 
Date: 
27 Nov 2020
Reviewer's report:
Major Comments
Abstract and Background: "Most patients with CYP7B1 deficiency succumb to
liver failure in early life." There are more reports of SPG5 due to CYP7B1
mutations than there are reports of liver failure due to CYP7B1 mutations. So I
think this should read, "Most reported patients with CYP7B1 mutations
presenting with liver disease in infancy have died of liver failure".
Page 3 and Figure 2. Urinary bile acid profiles. Interpretation of the spectra
would have been greatly enhanced by daughter ion scans. There is a very
prominent peak in the first spectrum with mass/charge ratio 480. While this
could be 
a glycine-conjugated tetrahydroxycholanoic acid (seen frequently in
infants with liver disease and/or on ursodeoxycholic acid), it could also be
taurine-conjugated 3beta-hydroxy-5-cholenoic acid and this was the largest peak
described for the 
CYP7B1 deficient patient 
in the Dai et al. paper. In the former
case the major daughter ion would be m/z 74; in the latter case, m/z 80. Bile acid
identities could also have been clarified by GC-MS
In the interpretation of subsequent urine bile acid analyses, a peak with
mass/charge ratio 510 
is interpreted as indicating the presence of glycine- and
sulphate- conjugated 3beta-hydroxy-5-cholenoic acid, however, children with
severe liver disease often excrete taurine-conjugated 7alpha,12alpha,3-oxo-4-
cholenoic acid which also has a mass/charge ratio of 510. These two bile acids
can again be distinguished by their principal daughter ions so tandem MS
analysis (or GC-MS) would have been helpful.
"Consequently, repeat testing combined with genetic analysis is usually
recommended in cases like this to definitively confirm the diagnosis". It is also
important to point out how difficult it is to interpret spectra from children who
are being treated with ursodeoxycholic acid and wherever possible samples
should be sent for analysis at least 2 weeks after stopping this treatment.
Minor Comments
Spaces between words missing: e.g. P2 "inCYP7B1(Fig.1)"
P2 "Physical examinations showed jaundice, groan and shortness of breath". I
am not sure what the authors are attempting to say with the word "groan".
Perhaps "groaning"; 
a sick child may groan but it is not a particularly useful sign.
Perhaps "grunting"; in the first few weeks of life he/she may grunt - a sign of
expiration against a partially closed glottis that indicates respiratory distress.
Also "shortness of breath" is a subjective sign that can be described by adults; for
infants it is more usual to describe what can be objectively observed e.g.
tachypnoea, grunting, recession, cyanosis.
"The laboratory investigations showed elevated levels of … 
total bile acids
(TBA), …" It is important to state the method being used for TBA analysis. It
was probably a method based on 3alpha-hydroxysteroid dehydrogenase; this
gives a low value for many children with inborn errors of bile acid synthesis
because synthesis of 3alpha-hydroxy bile acids is reduced. 
P4. "Recent lumbar magnetic resonance imaging (MRI) suggested physiological
bending become straightening..". 
I don't know what this means; the English
requires attention.
Figure 3. Arrows indicating the features described would help readers without
expertise in brain MRI interpretation.
P4. "By contrast, the acidic pathway is initiated by 27-hydroxylation of
cholesterol followed by 7
α
-hydroxylation of the monohydroxylated
intermediates 3
β
-hydroxy-5-cholestenoic and 3
β
-hydroxy-5-cholenoic acids to
yield CDCA [2, 13, 14], a reaction that is catalyzed by oxysterol-7
α
-hydroxylase
(CYP7B1)". Suggest "By contrast, the acidic pathway is initiated by 27-
hydroxylation of cholesterol followed by 7
α
-hydroxylation of the
monohydroxylated intermediates 3
β
-hydroxy-5-cholestenoic and 3
β
-hydroxy-5-
cholenoic acids, a reaction that is catalyzed by oxysterol-7
α
-hydroxylase
(CYP7B1); this pathway leads ultimately to 
production of CDCA [2, 13, 14]"
P5. "CDCA suppressed sterol 27-hydrolylase" > 27-hydroxylase
Publons Reviewer Recognition
. Springer Nature can send verification of this
review directly to Publons (a subsidiary of Clarivate Analytics). If you would
like to take advantage of this service, please click on the “Yes” option below.
Your name, email address, title of the reviewed manuscript, name of the journal,
and date of your review submission (the “Review Data”) will then be transmitted
to Publons after the final decision on the manuscript has been made. If you have
already registered at Publons, they will notify you of the receipt of this review
and update your profile 
as per your settings and their policy. If you are not
registered with Publons, you will receive an email from them asking you to
register in order for them to be able to recognize your review on your new
profile page. Publons may use the Review Data to generate derivative metadata
for the benefit of Publons and you as a reviewer, carefully considering the
sensitivity of such information. For example, Publons may verify your record as
a reviewer by updating your profile published on its webservice if you have
registered for such service or help editors to identify candidate reviewers. Please
find the details of processing in Publons’ privacy policy
https://publons.com/about/terms
Yes
Declaration of competing interests
Please complete a declaration of competing
interests, considering the following questions:
1
. 
Have you in the past five years received reimbursements, fees, funding, or
salary from an organisation that may in any way gain or lose financially
from the publication of this manuscript, either now or in the future?
2
. 
Do you hold any stocks or shares in an organisation that may in any way
gain or lose financially from the publication of this manuscript, either now
or in the future?
3
. 
Do you hold or are you currently applying for any patents relating to the
content of the manuscript?
4
. 
Have you received reimbursements, fees, funding, or salary from an
organization that holds or has applied for patents relating to the content of
the manuscript?
5
. 
Do you have any other financial competing interests?
6
. 
Do you have any non-financial competing interests in relation to this
paper?
If you can answer no to all of the above, write 'I declare that I have no competing
interests' below. If your reply is yes to any, please give details below.
'I declare that I have no competing interests'
Reviewer Publication Consent.
 I agree for my report to be made available
under an Open Access Creative Commons CC-BY License (
http://creativecommons.org/licenses/by/4.0
) if this manuscript is accepted for
publication. Any comments that I do not wish to be included in the published
report have been included as confidential comments to the editor, which will not
be published.
If you are not happy for us to publish this report, please contact the
editorial office before completing the review.
If you wish, you can include your
name in your published report. Please note you must decide whether to include
your name at the start of the process and confirm this decision whenever
prompted. If you change your decision later, we will not be able to publish your
name.
I agree to the terms of the CC-BY 4.0 license; please 
do not
 publish my name
with my report. (default)
Is the study design appropriate to answer the research question (including the use
of appropriate controls), and are the conclusions supported by the evidence
presented?
Yes
Are the methods sufficiently described to allow the study to be repeated?
Yes
Is the use of statistics and treatment of uncertainties appropriate?
Yes
Is the presentation of the work clear?
Yes
Are the images in this manuscript (including electrophoretic gels and blots) free
from apparent manipulation?
Yes
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