Expanding the phenotype of neurofibromatosis type 1 microdeletion syndrome

Abstract

AbstractNeurofibromatosis type 1 (NF‐1) microdeletion syndrome accounts for 5 to 11% of individuals with NF‐1. The aim of our study was to characterize a large cohort of individuals with NF‐1 microdeletion syndrome and expand its natural history. We conducted a retrospective chart review from 1994 to 2024 of individuals with NF‐1 microdeletion syndrome followed at two large Neurofibromatosis Clinics. This cohort consists of 57 individuals with NF‐1 microdeletion syndrome (28 type‐1, 4 type‐2, 2 type‐3, 9 atypical deletions, and 14 indeterminate). We note 38/56 (67.9%) with describable facial features, 25/57 (43.8%) with plexiform neurofibromas, and 3/57 (5.2%) with malignant peripheral nerve sheath tumors within the observed period. The most reported neurodevelopmental manifestations from school‐age or older individuals included 39/49 (79.6%) with developmental delays, 35/49 (71.4%) with expressive and/or receptive speech delays, 33/41 (80.5%) with learning difficulties, and 23/42 (54.8%) with attention‐deficit/hyperactivity disorder. Full‐scale IQ testing data was available for 22 individuals (range: 50–96). Of the 21 adults in this cohort, 14/21 (66.7%) graduated from high school, and 4/21 (19.0%) had some college experience. Many individuals received academic support (i.e., special education, individual education plan). In this cohort, neurocognitive outcomes in adults varied more than typically reported in the literature.