A clinical study of Brazilian patients with
neurofibromatosis type 1 (NF1) was performed in a multidisciplinary
Neurofibromatosis Program called
CEPAN (Center of Research and Service in
Neurofibromatosis). Among 55 patients (60% females, 40% males) who met the NIH criteria for the diagnosis of NF1, 98% had more than six café-au-lait patches, 94.5% had axillary freckling, 45% had inguinal freckling, and 87.5% had Lisch nodules. Cutaneous
neurofibromas were observed in 96%, and 40% presented
plexiform neurofibromas. A positive family history of NF1 was found in 60%, and
mental retardation occurred in 35%. Some degree of
scoliosis was noted in 49%, 51% had
macrocephaly, 40% had short stature, 76% had learning difficulties, and 2% had
optic gliomas. Unexpectedly high frequencies of
plexiform neurofibromas,
mental retardation, learning difficulties, and
scoliosis were observed, probably reflecting the detailed clinical analysis methods adopted by the
Neurofibromatosis Program. These same patients were screened for mutations in the GAP-related domain/GRD (exons 20-27a) by single-strand conformation polymorphism. Four different mutations (Q1189X, 3525-3526delAA, E1356G, c.4111-1G>A) and four polymorphisms (c.3315-27G>A, V1146I, V1317A, c.4514+11C>G) were identified. These data were recently published.