[Genetic diagnosis and follow-up study in pediatric neurofibromatosis 1 patients]

Objective: Based on the genetic diagnosis and follow-up study on pediatric neurofibromatosis 1 (NF1) patients, interrogating the genotype-phenotype correlations of patients with NF1 mutations. Methods: 32 Patients from age of 2 months to 5 years old (17 male and 15 female) suspected for neurofibromatosis 1 were recruited during September 2016 to January 2018 in Shanghai Children's Medical Center retrospectively. Genetic diagnosis was applied to detect pathogenic variants. Long-term follow-up study were conducted to reveal progress of the disease and genotype-phenotype correlations. Results: 27 patients were detected with pathogenic NF1 variants, among them three were not reported. 3 patients inherited pathogenic variants from their NF1 diagnosed parents, all the other variants were de novo. Progressive development of phenotypes wasn't observed in most patients during the follow-up (14/27). Some patients were diagnosed with short stature, pulmonary artery stenosis and developmental delay during the follow-up(7/27). Short stature and pulmonary artery stenosis may be associated with missense mutation and severe truncation mutation of NF1 gene, respectively. Conclusions: Genetic diagnosis is required in young patients of NF1.Follow-up plan of pediatric patients should be adjusted based on genetic findings. Early follow-up of cardiovascular abnormalities should be noted in patients with missense mutation. Height development in patients with severe truncating variants are needed.