The goal of this observational study (retrospective multicenter cohort study) is to learn if precision medicine approaches-including genetic testing, targeted drugs, and coordinated care from multiple specialists-can improve health outcomes and lower medical costs for people with neurocutaneous syndromes (NCS) in Western China, where healthcare resources are limited. NCS includes four main conditions: neurofibromatosis type 1 (NF1), tuberous sclerosis complex (TSC), Sturge-Weber syndrome (SWS), and von Hippel-Lindau disease (VHL). The main questions it aims to answer are:

• Do genetic testing and targeted drugs help people with NCS live longer without disease getting worse?
• Do these approaches better control seizures (for TSC and SWS) and shrink tumors (for NF1 and VHL)?
• Do they reduce the total cost of medical care?

Researchers will compare two groups to see the effects: participants who received precision medicine (genetic testing + targeted drugs + multidisciplinary care) versus those who received standard, uncoordinated care.

Participants will:

• Undergo genetic testing to identify specific gene changes linked to their NCS
• Receive targeted drugs (e.g., mTOR inhibitors for TSC, MEK inhibitors for NF1) if eligible
• Attend regular checkups, imaging scans (like MRI), and follow-up visits for an average of 11.4 years
• For those in the multidisciplinary care group, receive coordinated care from neurologists, geneticists, surgeons, and other specialists (with remote telemedicine visits for those living far from hospitals)

Inclusion Criteria:

* Confirmed diagnosis of one of the following neurocutaneous syndromes: Neurofibromatosis Type 1 (NF1) Tuberous Sclerosis Complex (TSC) Sturge-Weber Syndrome (SWS) Von Hippel-Lindau Disease (VHL) (Diagnosis established by established clinical criteria [e.g., NIH criteria for NF1, International TSC Consensus Criteria] or confirmed pathogenic genetic variant)

• Age between 0 and 65 years at the time of initial evaluation.
• Follow-up duration of at least 12 months at one of the participating tertiary medical centers in Western China:

West China Hospital, Sichuan University (Chengdu) Xinqiao Hospital, Army Medical University (Chongqing) The First Affiliated Hospital of Xi'an Jiaotong University (Xi'an)

*Availability of complete baseline clinical data, including: Demographic information Diagnostic workup Initial symptom profile Treatment history (if any)

Exclusion Criteria:

• Incomplete medical records- Key clinical, imaging, or genetic data missing, preventing reliable diagnosis or outcome assessment.
• Follow-up duration less than 12 months- Patients lost to follow-up or with insufficient longitudinal data to evaluate clinical outcomes.
• Diagnostic uncertainty- Cases that did not meet established clinical or genetic diagnostic criteria for NF1, TSC, SWS, or VHL (e.g., atypical presentations without molecular confirmation).
• Age > 65 years at initial evaluation- Although rare in neurocutaneous syndromes, patients older than 65 were excluded to maintain cohort relevance to typical disease onset and progression patterns.
• Participation in another interventional trial during the study period (if applicable)

The study included 1200 patients with neurocutaneous syndromes (NF1, TSC, SWS, or VHL) from three tertiary hospitals in Western China, recruited between 2015 and 2023. Participants were aged 0-65 years (median age at diagnosis: 8.2 years), with 69.3% under 18 years old and a slight male predominance (53.6%). All had confirmed diagnoses and at least 12 months of follow-up.