OBJECTIVETo explore the genetic etiology for 11 sporadic patients with neurofibromatosis type 1.

METHODSChip targeting capture and high-throughput sequencing were employed to detect potential mutations of NF1 and NF2 genes among the 11 patients. The data was filtered through multiple mutational databases and in-house whole exome sequence database. Sanger sequencing was used for analysis of family members of the patients.

RESULTSEleven pathogenic variants were found among the 11 patients, which included two splicing mutations, one missense mutation, two nonsense mutations, and six frame-shifting mutations. None of the mutations was recorded by the public database or the in-house database generated from 1775 samples through whole exome sequencing. None of the unaffected parents carried the same mutation. Seven mutations were associated with neurofibromatosis type 1 previously, while the remaining four were discovered for the first time. Prenatal diagnosis of two high-risk pregnancies suggested that neither fetus has inherited the NF1 mutation from their affected parents.

CONCLUSIONIdentification of causative mutations in patients with sporadic-type neurofibromatosis type 1 has provided a basis for genetic counseling. The four novel mutations have enriched the spectrum of NF1 gene mutations.