Natural history and genotype-phenotype correlation of pantothenate kinase-associated neurodegeneration

Aims To investigate the natural history and genotype-phenotype correlation of pantothenate kinase-associated neurodegeneration. Methods We collected data of patients with PKAN by searching from available publications in English and Chinese. Patients diagnosed in our center (Peking University First Hospital) were also included. The difference in natural history and genotype between early-onset (<10 year of age at onset) and late-onset patients (>= 10 year of age at onset) with PKAN was compared. Results A total of 248 patients were included. The median age at onset was 3.0 years in the early-onset group and 18.0 years in the late-onset group. Dystonia in lower limbs was the most common initial symptom in both groups. In the early-onset group, the median interval between the disease onset and occurrence of oromandibular dystonia, generalized dystonia, loss of independent ambulance was 6.0 years, 5.0 years, and 5.0 years. The corresponding values in late-onset group were 1.0 year, 4.0 years, and 6.0 years. About 20.0% died at median age of 12.5 years and 9.5 years after the onset in early-onset group. About 2.0% of the late-onset patients died during the follow-up. A total of 176 mutations were identified. Patients carrying two null alleles in PANK2 showed significantly earlier age of disease onset and progressed more rapidly to loss of independent ambulance. Conclusions This study provided a comprehensive review on the natural history and genotype of 248 patients with PKAN. The results will serve as a historical control data for future clinical trial on PKAN.