LAUSR

Paroxysmal nonkinesigenic dyskinesia (PNKD) is a rare movement disorder characterized by episodic attacks of involuntary movements. Mutations in the PNKD (MR-1) gene have been identified as a major genetic cause of PNKD. Primary familial brain calcification (PFBC) is an inheritable neurological disorder caused by heterozygous mutations in SLC20A2, PDGFRB, PDGFB, and XPR1. Here, we describe a Chinese family with 3 affected individuals demonstrating PNKD with PFBC, which is caused by a missense mutation in PDGFB. The proband (Fig. 1A, II:3) is a 36-year-old man who had jerky, involuntary movements of the limbs for 20 years. The involuntary movements occurred without obvious trigger factors and mainly appeared on the right side, lasting for a few seconds. Initially, the frequency of the attacks was >10 times per day, and later reduced with age. At present, the attacks occurred only several times in 1 year. During the episodes, he noted stiffening of the limbs, whereas headache, dizziness, and memory loss were not observed. The interictal EEG was normal. Brain CT scans at the age of 36 revealed severe bilateral calcifications involving globus pallidus, caudate nuclei, thalamus, and subcortical white matter (Fig. 1B). Serum levels of phosphate, calcium, and parathyroid hormone (PTH) were normal. Patient II:1 (Fig. 1A) is the elder sister of the proband. At the age of 5, she experienced involuntary limb movements similar to those of the proband, which were mostly observed on the left side. The frequency of attacks decreased from two to three times per day at onset to several times per year after the third decade. She also showed anxiety sometimes. Brain CT scans at age 40 revealed multiple calcifications in globus pallidus and putamen (Fig. 1C). Serum levels of calcium, phosphate, and PTH were normal. Patient III:1 (Fig. 1A) is a 10-year-old boy who started having dystonic movements of the limbs at the age of 1. Initially, the attacks lasted for a few seconds and occurred one to two times per day. As his age increased, the attacks TABLE 1. Associations between measures of disease progression and plasma cytokines in 124 Huntington’s disease gene expansion carriers