Bilateral Pheochromocytoma with Germline MAX Variant without Family History

Round 1

Reviewer 1 Report

The paper is a report of a case of bilateral pheochromocytoma (PCC) with a variant in the MYC-associated factor X (MAX) gene (c.295+1G>A). There are a few points in the paper that would benefit from clarification

Major comment:

 The allelic variant found in the patient, as mentioned by the authors, was described in a study developed by exome analysis. In the mentioned study they conclude that the presence of germline mutations in the patients, as well as the loss of heterozygosity of the wild-type allele and the absence of protein in the tumors, indicated that MAX is a tumor-suppressor gene that causes hereditary PCC.

MAX gene is located in chromosome 14 and it is an imprinting gene, which leads to the importance to segregation analysis. Only allelic variant inherited from pattern allele can be associated to the phenotype. The maternal allele is silenced and not expressed.

I understand the negative of the family to participated to the study, but all results of the case report are based only in a previously study and the immunohistochemistry analysis. Perhaps the study of loss of heterozygosity in the tumor as well as the analysis of UPD regarding the imprint of Max gene could better strengthen the result obtained.

If it is not possible to carry out these experiments it would be interesting to emphasize better the non-requirement of somatic evaluation based on the broader literature, in the results obtained (emphasize more in the text the immunohistochemistry results) and the non-participation of other family members in the study.

Specific comments:

 Line 70:

The allelic variant c.295+1g>a need more details:

• The allelic variant is described and has a reference SNP (rs786203385). But I have to check in database this information, it’s very important show this information.
• It is not informed the transcript used for PCR test. It’s necessary inform the RefSeq MN or Ensembl transcript information.
• It also important inform if is a rare allelic variant and the ACMG (The American College of Medical Genetics and Genomics) classification: Pathogenic, likely pathogenic, VUS, Benign or likely benign.

 Line 80: Figure 1

In the pedigree figure it’s necessary add the roman numerals (I, II, III) representing generations and the numbering representing each individual. After these changes the number corresponding the age will not make the figure so confused.

 Line 108:

I understand the refusion of the family in the segregation analysis, but if the study was not performed, the inheritance pattern cannot be subjectively estimated.

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Reviewer 2 Report

Hata and colleagues provide a brief and interesting case report of a male aged 40 coincidentally diagnosed with bilateral pheochromocytoma. The patient has no prior history and family history is inconspicuous as well. The report is well written and concise. It is a useful addition to the growing body of reports on MAX mutations. There is no information missing.

Minor corrections:
* The wording is odd in some places (cf. annotations attached). Please revise.
* It is unclear what "the health screening" is.
* Consider adding the excellent and recent review by Jhawar and colleagues on PPGL genetics, DOI 10.3390/cancers14030594.

Comments for author File: Comments.pdf

Author Response

Please see the attachment.

Author Response File: Author Response.docx