Young-onset parkinsonism in a Hong Kong Chinese man with adult-onset Hallervorden-Spatz syndrome

Neurodegeneration with brain iron accumulation (NBIA) is a heterogeneous group of disorders varied in genetic etiologies, clinical presentations, and radiological features. NBIA is an iron homeostasis disorder with progressive iron accumulation in the central nervous systems and is clinically characterized by extrapyramidal movement abnormalities, retinal pigmentary changes, and cognitive impairment. Panthothenate kinase-associated neurodegeneration (Hallervorden-Spatz disease) is the commonest disorder of NBIA with a prevalence of one-three per million. Clinically, it is classified into early-onset childhood, atypical late-onset, and adult-onset type. Adult-onset type is rarer. We report the first case of adult-onset panthothenate kinase-associated neurodegeneration in Hong Kong in a 28-year-old Chinese man who presented with pure young-onset parkinsonism. Magnetic resonance imaging (MRI) of the brain showed the presence of eye-of-the-tiger sign. Two compound heterozygous mutations PANK2 NM_153638.2: c.445G > T; NP_705902.2: p.E149X and PANK2 NM_153638.2: c.1133A > G; NP_705902.2: p.D378G were detected. Parkinsonism per se is a very heterogeneous phenotypic group. In view of the readily available genetic analysis of PANK2, panthothenate kinase-associated neurodegeneration should be considered in adult patients with young-onset parkinsonism with or without the eye-of-the-tiger sign. The exact diagnosis offers a different management approach and genetic counseling. NBIA is likely under- or misdiagnosed in Hong Kong Chinese.