Diffuse hypomyelination is not obligate for POLR3-related disorders

作者：La Piana Roberta; Cayami Ferdy K; Tran Luan T; Guerrero Kether; van Spaendonk Rosalina; Ounap Katrin; Pajusalu Sander; Haack Tobias; Wassmer Evangeline; Timmann Dagmar; Mierzewska Hanna; Poll The Bwee T; Patel Chirag; Cox Helen; Atik Tahir; Onay Huseyin; Ozkinay Ferda; Vanderver Adeline; van der Knaap Marjo S; Wolf Nicole I; Bernard Genevieve^*

来源：Neurology, 2016, 86(17): 1622-1626.

DOI：10.1212/WNL.0000000000002612

Objective:To report atypical MRI patterns associated with POLR3A and POLR3B mutations.Methods:This was a multicenter retrospective study to collect neuroradiologic, clinical, and molecular data of patients with mutations in POLR3A and POLR3B without the classic MRI phenotype, i.e., diffuse hypomyelination associated with relative T2 hypointensity of the ventrolateral thalamus, globus pallidus, optic radiation, corticospinal tract at the level of the internal capsule, and dentate nucleus, cerebellar atrophy, and thinning of the corpus callosum.Results:Eight patients were identified: 6 carried mutations in POLR3A and 2 in POLR3B. We identified 2 novel MRI patterns: 4 participants presented a selective involvement of the corticospinal tracts, specifically at the level of the posterior limbs of the internal capsules; 4 patients presented moderate to severe cerebellar atrophy. Incomplete hypomyelination was observed in 5 participants.Conclusion:Diffuse hypomyelination is not an obligatory feature of POLR3-related disorders. Two distinct patterns, selective involvement of the corticospinal tracts and cerebellar atrophy, are added to the MRI presentation of POLR3-related disorders.

• 出版日期2016-4-26