Teaching NeuroImages: Beaking in the brainstem A diagnostic clue

Summary

Terminology

Original

  • 2yo M
  • C/C
    • 8mo
    • developmental regression
    • progressive stiffening of limb
    • strabismus
  • Ex
    • axonal sensorimotor neuropathy
    • MRI
    • genome
      • PLA2G6 gene
  • Dx
    • INAD (Infantile neuroaxonal dystrophy)

A 2-year-old boy presented with developmental regression, progressive stiffening of limbs, and strabismus since the age of 8 months. A child of consanguineous parents, he had a similarly affected older brother. Nerve conduction studies were suggestive of an axonal sensorimotor neuropathy. A diagnosis of infantile neuroaxonal dystrophy (INAD) was concluded based on a suggestive MRI (figure) and the detection of a pathogenic homozygous variant in the PLA2G6 gene (c.T2370G).

Figure

Fig

Figure
MRI of the brain in a child with PLA2G6-associated infantile neuroaxonal dystrophy (INAD)
Midline sagittal T1-weighted sequences demonstrate claval hypertrophy (A, yellow arrow), shallow optic chiasm (A, white arrow), vertically oriented splenium of the corpus callosum (B, arrowhead), and cerebellar atrophy (A and B, red arrow). The T2-weighted (C) and fluid-attenuated inversion recovery (FLAIR) (D) sequences show hyperintense signal changes in bilateral cerebellar hemisphere with prominent folia (star) and inferior vermian atrophy (arrow) in a child with PLA2G6-associated INAD. T2-weighted (E) and FLAIR (F) sequences did not show any iron deposition in globus pallidus.

  • changes
    • brainstem
    • corpus callosum
  • atrophy
    • cerebellum

INAD belongs to the family of PLA2G6-associated neurodegeneration.1 In a child with infantile neuroregression, the peculiar changes in the brainstem and corpus callosum in the presence of cerebellar atrophy serve as a guide to further genetic testing for this disorder.2

Refenreces

  1. Romani M , Kraoua I, Micalizzi A, et al. Infantile and childhood onset PLA2G6-associated neurodegeneration in a large North African cohort. Eur J Neurol 2015;22:178–186.
  2. Illingworth MA, Meyer E, Chong WK, et al. PLA2G6-associated neurodegeneration (PLAN): further expansion of the clinical, radiological and mutation spectrum associated with infantile and atypical childhood-onset disease. Mol Genet Metab 2014;112:183–189.