Characteristic MRI pattern in LMNB1-related autosomal dominant leukodystrophy: a case report

Adult-onset autosomal dominant leukodystrophy (ADLD) is an ultra-rare inherited white matter disorder caused by variants in the LMNB1 gene. Here, we report a case of ADLD and characterize its typical magnetic resonance imaging (MRI) features, with the aim of facilitating its clinical recognition and differential diagnosis.

The patient was a 55-year-old male who had experienced incomplete voiding, dysuria, and constipation for 10 years. One year prior to presentation, he developed lower limb weakness and unsteady gait, which progressively worsened over time. Brain MRI revealed extensive white matter abnormalities, including a symmetric hyperintensity pattern in the brainstem corticospinal tract and bilateral middle cerebellar peduncles on T2-weighted/FLAIR images, which resembled the facial profile of a Beagle dog. Subsequent genetic testing identified a pathogenic duplication of the LMNB1 gene, a typical variant associated with ADLD.

We report a case of ADLD caused by LMNB1 duplication with a typical clinical course and characteristic MRI features. Its characteristic MRI features, including the "Beagle sign" as an illustrative imaging analogy in the brainstem, may facilitate the clinical recognition and differential diagnosis of this disorder.