Children with Rett syndrome are in a period of rapid growth, and proper and appropriate nutritional support is very important. Past foreign research papers it has been pointed out that most of these patients have feeding difficulties, dysphagia, and digestive tract abnormalities, are often constipated, and may suffer from osteoporosis and other problems. Lack of proper nutritional support will seriously affect their growth, development and health. in view of There is a lack of relevant research in China, so the investigators would like to use this research to explore the nutritional, growth and postural status of Rett's disease patients, as the reference direction and goal of dietary adjustment and nutritional support for patients, and establish dietary and nutritional strategies for sick children in Taiwan.

Inclusion Criteria:

• Rett syndrome patient.

Exclusion Criteria:

• Not Rett syndrome patient.

Rett syndrome patient.

Assessment of nutritional and growth status in Rett syndrome patient