The Letter reports on a case of a patient with hypereosinophilic syndrome for whom a heterozygous pathogenic nonsense variant in CARD11, c.2671C>T77 (p.Arg891*) has been identified.
The case report is interesting.
I have no major concerns.
However, I have some suggestions that could be implemented.
1) The age of onset of the different clinical manifestations is unclear as it is the age at the initiation of the different treatments. A comprehensive timeline detailing all the clinical manifestations and treatments is fundamental to facilitate the reader’s understanding of the case.
2) A figure/table showing the longitudinal data points of the main laboratory tests (including the eosinophil count) may help interpret the case.
3) Additional details on the mutation should be reported.
4) Additional details on eosinophilic enteropathy should be reported. Are biopsies available? How many eosinophils per hpf are reported? The Authors state that the colitis was initially diagnosed as ulcerative colitis. This point needs to be clarified better.
5) Chronic recurrent multifocal osteomyelitis (CRMO) diagnosis should be further discussed and contextualized.
6) The case follow-up should be better clarified. “At presentation, the patient was taking tofacitinib for treatment of ulcerative colitis. For CRMO, he was prescribed pamidronate. He was started on dupilimab 300 mg weekly, as well as glutamine supplementation 5 g twice daily”. Was tofacitinib discontinued? Pamidronate? Was the therapy with dubilumab effective?

Please revise the text for typos:
e.g. "heterzygous" line 76

The Authors adequately addressed the comments.