Phenotypic characterization of neurofibromatosis type 1 in a large Chinese cohort: A cross-sectional study.

Background: Neurofibromatosis type 1 (NF1) is a multisystemic genetic disorder characterized by NF1 gene mutations. The well-described manifestations of NF1 are primarily derived from European populations. Objective: To evaluate the phenotypic characteristics of Chinese patients with NF1. Methods: This cross-sectional, multicenter study involved patients with NF1 from Chinese and U.S. populations. Clinical data were obtained from NF1 clinics and patient-reported outcome assessments. Findings: 1313 patients with Chinese NF1 were included. We found that Chinese patients were diagnosed later in life and exhibited a lower prevalence of spinal neurofibromas and fractures but a higher rate of malignant peripheral nerve sheath tumors as compared to U.S. patients. Four distinct NF1 subtypes were identified: severe neural, cutaneous, hereditary, and mild. Significant correlations were observed between freckles and cutaneous neurofibromas and between bone lesions and pseudarthrosis. Cutaneous manifestations were correlated with systemic manifestations, and the risk of developing plexiform neurofibromas was inversely proportional to the number of cutaneous neurofibromas and freckles. Limitations: The use of self-report data may introduce subjectivity and recall bias. Conclusion: This study provides the first comprehensive analysis of clinical phenotypes in Chinese patients with NF1. The identification of distinct NF1 subtypes, phenotypic correlations, and ethnic differences supports more personalized management strategies for NF1 patients.