Prenatal Diagnosis of Neurofibromatosis Type 1: No Specific Prenatal Features Observed in Sporadic Fetal Presentations

OBJECTIVE: To present the indications for prenatal diagnosis (PND) of neurofibromatosis type 1 (NF1) in a Chinese referral medical center. METHOD: This study encompasses a 7-year experience in PND of NF1. The cohort consisted of women undergoing PND due to parental carrier status, as well as those whose fetuses were diagnosed with copy number variations (CNVs) involving NF1 gene or NF1 variants based on indications unrelated to parental carrier status. RESULTS: A total of 30 cases underwent PND related to NF1. Among these, 17 cases involved a parental carrier, with pathogenic NF1 variants identified in ten fetuses while absent in seven others. Additionally, 13 cases were diagnosed incidentally during gestation due to reasons not linked to parental carrier status; this included seven instances where the indications were advanced maternal age or increased nuchal translucency and six cases presenting abnormal nonspecific fetal ultrasound findings. Within this cohort, we identified a total of 21 distinct NF1 variants across 24 unrelated cases, with c.4600C > T; p.(Arg1534Ter) being the only recurrent variant observed. CONCLUSIONS: NF1 does not exhibit specific prenatal features; sporadic fetal cases were diagnosed incidentally via the use of advanced genetic testing methods.