TY - JOUR
T1 - Regional Difference in Myelination in Monocarboxylate Transporter 8 Deficiency
T2 - Case Reports and Literature Review of Cases in Japan
AU - Iwayama, Hideyuki
AU - Tanaka, Tatsushi
AU - Aoyama, Kohei
AU - Moroto, Masaharu
AU - Adachi, Shinsuke
AU - Fujisawa, Yasuko
AU - Matsuura, Hiroki
AU - Takano, Kyoko
AU - Mizuno, Haruo
AU - Okumura, Akihisa
N1 - Publisher Copyright:
© Copyright © 2021 Iwayama, Tanaka, Aoyama, Moroto, Adachi, Fujisawa, Matsuura, Takano, Mizuno and Okumura.
PY - 2021/7/15
Y1 - 2021/7/15
N2 - Background: Monocarboxylate transporter 8 (MCT8) is a thyroid hormone transmembrane transporter protein. MCT8 deficiency induces severe X-linked psychomotor retardation. Previous reports have documented delayed myelination in the central white matter (WM) in these patients; however, the regional pattern of myelination has not been fully elucidated. Here, we describe the regional evaluation of myelination in four patients with MCT8 deficiency. We also reviewed the myelination status of previously reported Japanese patients with MCT8 deficiency based on magnetic resonance imaging (MRI). Case Reports: Four patients were genetically diagnosed with MCT8 deficiency at the age of 4–9 months. In infancy, MRI signal of myelination was observed mainly in the cerebellar WM, posterior limb of internal capsule, and the optic radiation. There was progression of myelination with increase in age. Discussion: We identified 36 patients with MCT8 deficiency from 25 families reported from Japan. The available MRI images were obtained at the age of <2 years in 13 patients, between 2 and 4 years in six patients, between 4 and 6 years in three patients, and at ≥6 years in eight patients. Cerebellar WM, posterior limb of internal capsule, and optic radiation showed MRI signal of myelination by the age of 2 years, followed by centrum semiovale and corpus callosum by the age of 4 years. Most regions except for deep anterior WM showed MRI signal of myelination at the age of 6 years. Conclusion: The sequential pattern of myelination in patients with MCT8 deficiency was largely similar to that in normal children; however, delayed myelination of the deep anterior WM was a remarkable finding. Further studies are required to characterize the imaging features of patients with MCT8 deficiency.
AB - Background: Monocarboxylate transporter 8 (MCT8) is a thyroid hormone transmembrane transporter protein. MCT8 deficiency induces severe X-linked psychomotor retardation. Previous reports have documented delayed myelination in the central white matter (WM) in these patients; however, the regional pattern of myelination has not been fully elucidated. Here, we describe the regional evaluation of myelination in four patients with MCT8 deficiency. We also reviewed the myelination status of previously reported Japanese patients with MCT8 deficiency based on magnetic resonance imaging (MRI). Case Reports: Four patients were genetically diagnosed with MCT8 deficiency at the age of 4–9 months. In infancy, MRI signal of myelination was observed mainly in the cerebellar WM, posterior limb of internal capsule, and the optic radiation. There was progression of myelination with increase in age. Discussion: We identified 36 patients with MCT8 deficiency from 25 families reported from Japan. The available MRI images were obtained at the age of <2 years in 13 patients, between 2 and 4 years in six patients, between 4 and 6 years in three patients, and at ≥6 years in eight patients. Cerebellar WM, posterior limb of internal capsule, and optic radiation showed MRI signal of myelination by the age of 2 years, followed by centrum semiovale and corpus callosum by the age of 4 years. Most regions except for deep anterior WM showed MRI signal of myelination at the age of 6 years. Conclusion: The sequential pattern of myelination in patients with MCT8 deficiency was largely similar to that in normal children; however, delayed myelination of the deep anterior WM was a remarkable finding. Further studies are required to characterize the imaging features of patients with MCT8 deficiency.
KW - Allan-Herdon-Dudlley syndrome
KW - delayed myelination
KW - magnetic resonance imaging
KW - monocarboxylate transporter 8 deficiency
KW - reginal analysis
KW - thyroid hormone transporter
KW - white matter
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U2 - 10.3389/fneur.2021.657820
DO - 10.3389/fneur.2021.657820
M3 - Article
AN - SCOPUS:85111609696
SN - 1664-2295
VL - 12
JO - Frontiers in Neurology
JF - Frontiers in Neurology
M1 - 657820
ER -