Pantothenate kinase-associated neurodegeneration (PKAN) is an autosomal recessive disorder that results from mutations in the PANK2 gene. There are two recognized phenotypes for this condition: classic PKAN and atypical PKAN. Although dystonia is a prominent finding in classic PKAN – characterized by early onset of symptoms (age <6 years), intellectual impairment, retinal degeneration, and other extrapyramidal symptoms – it is a rare presenting symptom in atypical PKAN, which has later onset (age >10 years) and consists of speech abnormalities, psychiatric disturbances, and more gradual progression. The genotype for atypical PKAN is highly diverse with many combinations of PANK2 variants yet to be described.

We present the case of a 22-year-old female from Nicaragua who presented with involuntary movements while chewing. Her parents further reported “clumsiness” since age 5, mild learning difficulties since age 9, and slurred speech since age 17. She had history of multiple motor vehicle accidents and was later found to have retinal dysfunction. Family history revealed one paternal aunt with psychosis and one with intellectual disability. Exam was significant for mild truncal dystonia in addition to a complex craniocervical dystonia present while eating, characterized by stiffening of the bilateral sternocleidomastoids, jaw opening dystonia, abnormal tongue movements, and worsening blepharospasm. MRI brain showed bilateral “eye of the tiger” pattern. Importantly, genetic testing was positive for a novel combination of compound heterozygous mutations, including a known PANK2 pathogenic variant, c.1176_1177del (p.Val394Ter), plus a PANK2 variant of uncertain significance (VUS), c.1147T>C (p.Tyr383His), likely a pathogenic mutation interfering with protein formation.

Our case contributes to the growing literature characterizing both the phenotype and genotype (with a novel PANK2 mutation) of atypical PKAN, and suggests a low threshold for PKAN work-up in young adults presenting with feeding dystonia.