Deletion of the entire NF1 gene causing distinct manifestations in a family.

We identified a father and son with neurofibromatosis type 1 (NF1) due to a deletion of the entire NF1 gene detected by fluorescence in situ hybridization (FISH). As is the case for others reported to have such large deletions, father and son had severe NF1, including a large number of cutaneous neurofibromas, facial anomalies, large hands, feet, and head, and developmental impairment. They were discordant in that seizures and plexiform neurofibromas occurred only in the propositus. Large NF1 deletions can be compatible with familial transmission and appear to be associated with a distinct phenotype.