We analyzed the clinical characteristics of 24 patients with riboflavin-responsive lipid deposition myopathy (RR-LSM) (from 20 RR-LSM families in the northern part of mainland China, of which 16 families had 1 patient each and the remaining 4 families had 2 patients each). Twenty-four patients, 11 asymptomatic family members, and 100 healthy individuals were examined for ETFDH genes. 24 patients were (27.9±9.9) years old at onset, and the main symptoms were weakness of limbs (21 patients, 87.5%), difficulty in chewing (15 patients, 62.5%), weakness of neck muscles (14 patients, 58.3%), and myalgia (14 patients, 58.3%). 18 patients had blood metabolic screenings suggesting that they had a weakness of limbs (21 patients, 87.5%), difficulty in chewing (15 patients, 62.5%), and myalgia (14 patients, 58.3%). patients had blood metabolic screens suggestive of elevated lipoylcarnitine, and glutaric aciduria was present in 15 of the 17 patients. We found 18 ETFDH gene point mutations in 19 families, including 13 missense mutations, 2 shear mutations, 2 nonsense mutations and 1 synonymous mutation. Among the patients, 998A>G, 1450T>C, 1703T>C, 1717C>T, 821G>A, 643G>A, 251C>T, 1763A>T, 369T>A, IVS7+2T>C, and IVS6+1G>A were not present in 100 healthy individuals. Nine lines had the 770A>G (Y257C) mutation; five lines had the 1227A>C (L409F) mutation. Many new mutations in ETFDH gene suggest that there may be a specific mutation spectrum in RR-LSM in Chinese, among which Y257C and L409F mutations may be hotspot mutations in the northern part of mainland China.