The first guidebook for the diagnosis and treatment of rare diseases in China was released on Wednesday.

The guide includes definitions of 121 rare diseases included in the catalogue released by the National Health Commission, their causes, and procedures for diagnosis and treatment, according to Peking Union Medical College Hospital, a major drafter of the guide.

Zhang Zongjiu, chief for medical administration and supervision at the National Health Commission, said release of the guide will greatly improve diagnosis and treatment of rare diseases and benefit patients. Experts also borrowed related international guides in drafting it, he said.

"Although incidences of rare diseases are very low, cases of rare diseases in China are not rare due to China's big population," he said. "In general, medical institutions in China lack enough skills to effectively diagnose and treat rare diseases, and the guide can be of great significance to conducting training among medical staff and improving their skills for diagnosis and treatment," Zhang said.