[New MDS Criteria for the Diagnosis of Multiple System Atrophy: Overview and Genetic Viewpoint]

A new diagnostic criteria for multiple system atrophy, "The Movement Disorder Society Criteria for the Diagnosis of Multiple System Atrophy (MSA)", has been proposed. Under the new criteria, new categories of "clinically established MSA," "clinically probable MSA," and "possible prodromal MSA" have been introduced. The new diagnostic criteria is expected to facilitate early and accurate diagnosis of MSA in clinical practice for MSA patients and clinical trials for MSA. In the diagnostic criteria, "A sporadic, progressive adult (>30 years) onset disease" is described as an "essential feature of MSA," and thus attention to familial occurrence of MSA is not included. Familial occurrence of MSA, however, was recognized first in Japan, and later in the world. We have witnessed discoveries of numerous genes underlying other neurodegenerative diseases, including Parkinson disease, and therefore application of molecular genetics research for MSA is highly expected to contribute to elucidating the molecular basis of MSA. Although the new diagnostic criteria is designed to facilitate early and accurate diagnosis of sporadic MSA, we simultaneously need to pay attention to familial occurrence of MSA and promotion of molecular genetics research of MSA.