Paroxysmal Kinesigenic Dyskinesia in Twins With Chromosome 16p11.2 Duplication Syndrome

Paroxysmal kinesigenic dyskinesia (PKD) (MIM# 128200) is a movement disorder characterized by brief episodes of involuntary movements consisting of dystonia, chorea, or myoclonus, usually triggered by sudden voluntary movements.1 Pathogenic variants in PRRT2 (MIM# 614386), located on chromosome 16p11.2, have been identified as the most common cause of PKD.2 Most of the reported patients (approximately 80%) had the frameshift pathogenic variant c.649dupC (p. Arg217Profs*8), which causes a premature stop codon. Other reported variants are nonsense, frameshift, or rarely missense that are predicted to cause a truncated protein, absence of protein product through nonsense-mediated mRNA decay, or nonfunctional protein.3 Isolated PKD is typically associated with heterozygous intragenic variants in PRRT2. Symptomatic PKD has been reported in 6 patients with 16p11.2 microdeletion syndrome (MIM# 611913).4 PKD is thus postulated to result from PRRT2 haploinsufficiency. The reciprocal chromosome 16p11.2 duplication syndrome (MIM# 614671) is associated with autism, ADHD, developmental delay, intellectual disability, epilepsy, hypotonia, congenital anomalies, and microcephaly5,6 but has not until now been associated with PKD.

Read article at journal's website

Related Articles


Your email address will not be published. Required fields are marked *