Pantothenate kinase-associated neurodegeneration (PKAN) in a child with Down syndrome. A case report and follow-up with MRI

Abstract

Neurodegeneration with brain iron accumulation (NBIA) is a subtype of inherited metabolic disorders. It includes pantothenate kinase-associated neurodegeneration (PKAN), which is a rare autosomal recessive disorder caused by the mutation of pantothenate kinase 2-gene (PANK2). It affects the deep grey matter nuclei causing progressive extrapyramidal motor impairment.1 We present a case of genetically proven PKAN in a child with mosaic trisomy 21 in which T2- hyperintensity of the basal ganglia was seen followed by the classic eye-of-the-tiger sign in a follow-up MRI.

Figure 1.

MRI of the brain at the age of 27 months (a–c) and at the age of 5 years (d–f). (a,d) Axial fluid-attenuated inversion recovery, (b,e) axial T ₂* GRE, (c,f) axial b0 of diffusion weighted imaging. The upper row at the age of 27 months showing bilateral T ₂ hyperintensity in the medial globus pallidus (arrows in a) and no remarkable signal changes in the T ₂* images at this age. In the follow-up MRI at the age of 5 years (lower row), there is obvious new hypointense signal in the T ₂* GRE in the lateral global pallidus bilaterally (arrows in e) with hyperintensity medially (arrows in d). GP, GRE, gradient recalled echo.

Figure 2.

Magnified images of the basal ganglia of the MRI performed at the age of 5 years, showing a hyperintense signal at the medial globus pallidus in axial fluid-attenuated inversion recovery (a) and a hypointense signal at the lateral globus pallidus , especially at the T ₂* sequence (b). The combination of these signals is known as the eye-of-the-tiger sign (c). Source of image (c): http://heroschool.us/youve-got-the-eye-of-the-tiger/