MCT8甲状腺激素转运体与艾伦-赫ndon-达德利综合征。
The MCT8 thyroid hormone transporter and Allan-Herndon-Dudley syndrome.
作者信息
Schwartz Charles E, Stevenson Roger E
机构信息
JC Self Research Institute of Human Genetics, Greenwood Genetic Center, Greenwood, SC, USA.
出版信息
Best Pract Res Clin Endocrinol Metab. 2007 Jun;21(2):307-21. doi: 10.1016/j.beem.2007.03.009.
Thyroid hormone is essential for the proper development and function of the brain. The active form of thyroid hormone is T(3), which binds to nuclear receptors. Recently, a transporter specific for T(3), MCT8 (monocarboxylate transporter 8) was identified. MCT8 is highly expressed in liver and brain. The gene is located in Xq13 and mutations in MCT8 are responsible for an X-linked condition, Allan-Herndon-Dudley syndrome (AHDS). This syndrome is characterized by congenital hypotonia that progresses to spasticity with severe psychomotor delays. Affected males also present with muscle hypoplasia, generalized muscle weakness, and limited speech. Importantly, these patients have elevated serum levels of free T(3), low to below normal serum levels of free T(4), and levels of thyroid stimulating hormone that are within the normal range. This constellation of measurements of thyroid function enables quick screening for AHDS in males presenting with cognitive impairment, congenital hypotonia, and generalized muscle weakness.
甲状腺激素对于大脑的正常发育和功能至关重要。甲状腺激素的活性形式是T(3)，它与核受体结合。最近，一种特异性转运T(3)的转运蛋白，即单羧酸转运蛋白8（MCT8）被发现。MCT8在肝脏和大脑中高度表达。该基因位于Xq13，MCT8的突变会导致一种X连锁疾病，即艾伦-赫ndon-达德利综合征（AHDS）。这种综合征的特征是先天性肌张力减退，随后发展为痉挛，并伴有严重的精神运动发育迟缓。受影响的男性还表现出肌肉发育不全、全身肌肉无力和言语受限。重要的是，这些患者的血清游离T(3)水平升高，血清游离T(4)水平低至低于正常范围，但促甲状腺激素水平在正常范围内。这种甲状腺功能测量结果的组合能够快速筛查出患有认知障碍、先天性肌张力减退和全身肌肉无力的男性中的AHDS。
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