Reply:

We appreciate that Guerrini-Rousseau and colleagues are raising awareness for constitutional mismatch repair deficiency (CMMRD) syndrome and its phenotypical overlap with neurofibromatosis type 1 (NF-1). All 5 patients described in our article met clinical criteria for NF-1 (Table). None of the patients reported had confirmatory genetic testing; for children who meet the clinical criteria, genetic testing is not typically obtained.

CMMRD is rare (200 patients reported), and our patients had none of the other diagnostic criteria of CMMRD.¹ Café au lait spots are common (up to 97%) in CMMRD, but the other clinical manifestations of NF-1 are much less frequent.² Focal abnormal signal intensities have also been reported in CMMRD.

• © 2019 by American Journal of Neuroradiology