POLR3A和POLR3B突变之间小脑异常和髓鞘形成不足的不同模式。
Different patterns of cerebellar abnormality and hypomyelination between POLR3A and POLR3B mutations.
作者信息
Takanashi Jun-ichi, Osaka Hitoshi, Saitsu Hirotomo, Sasaki Masayuki, Mori Harushi, Shibayama Hidehiro, Tanaka Manabu, Nomura Yoshiko, Terao Yasuo, Inoue Ken, Matsumoto Naomichi, Barkovich A James
机构信息
Department of Pediatrics, Kameda Medical Center, Kamogawa, Japan; Department of Radiology, Toho University Sakura Medical Center, Sakura, Japan.
Division of Neurology, Clinical Research Institute, Kanagawa Children's Medical Center, Yokohama, Japan.
出版信息
Brain Dev. 2014 Mar;36(3):259-63. doi: 10.1016/j.braindev.2013.03.006. Epub 2013 May 3.
BACKGROUND
Mutations of POLR3A and POLR3B have been reported to cause several allelic hypomyelinating disorders, including hypomyelination with hypogonadotropic hypogonadism and hypodontia (4H syndrome).
PATIENTS AND METHODS
To clarify the difference in MRI between the two genotypes, we reviewed MRI in three patients with POLR3B mutations, and three with POLR3A mutations.
RESULTS
Though small cerebellar hemispheres and vermis are common MRI findings with both types of mutations, MRI in patients with POLR3B mutations revealed smaller cerebellar structures, especially vermis, than those in POLR3A mutations. MRI also showed milder hypomyelination in patients with POLR3B mutations than those with POLR3A mutations, which might explain milder clinical manifestations.
CONCLUSIONS
MRI findings are distinct between patients with POLR3A and 3B mutations, and can provide important clues for the diagnosis, as these patients sometimes have no clinical symptoms suggesting 4H syndrome.
背景
据报道，POLR3A和POLR3B的突变会导致多种等位基因性低髓鞘形成障碍，包括伴有低促性腺激素性性腺功能减退和牙发育不全的低髓鞘形成（4H综合征）。
患者与方法
为了阐明两种基因型在MRI上的差异，我们回顾了3例POLR3B突变患者和3例POLR3A突变患者的MRI检查结果。
结果
虽然小脑半球和蚓部较小是这两种类型突变常见的MRI表现，但POLR3B突变患者的MRI显示小脑结构，尤其是蚓部，比POLR3A突变患者的更小。MRI还显示，POLR3B突变患者的低髓鞘形成程度比POLR3A突变患者更轻，这可能解释了其临床表现较轻的原因。
结论
POLR3A和3B突变患者的MRI表现不同，可为诊断提供重要线索，因为这些患者有时没有提示4H综合征的临床症状。
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