López-Marín Laura, Martín-Belinchón Mónica, Gutiérrez-Solana Luis G, Morte-Molina Beatriz, Duat-Rodríguez Anna, Bernal Juan
Sección de Neuropediatría, Hospital Infantil Universitario Niño Jesús.
Rev Neurol. 2013 Jun 16;56(12):615-22.
MCT8 is a specific transporter for the T4 and T3 thyroid hormones that allows their entry in the brain and other organs. Mutations in MCT8 (Allan-Herndon-Dudley syndrome) lead to a severe form of X-linked psychomotor retardation, which is characterised by elevated plasma T3 and low T4.
We describe the first case diagnosed in Spain with this syndrome and review the published literature about this topic. We both review the various clinical presentations, genetic advances, differential diagnosis and therapeutic perspectives of this syndrome and propose a diagnostic algorithm for it.
A 5 year-old boy, with a clinical picture compatible with Pelizaeus-Merzbacher disease. PLP1 gene sequencing showed no abnormalities. All the genetic and metabolic studies conducted were normal. Finally, a complete study of thyroid profile revealed abnormalities that were consistent with MCT8 transporter deficiency. The sequencing of the SLC16A2 gene (MCT8) showed a mutation in exon 3 and the study made at a cellular level, has confirmed that this mutation changes the properties of the protein.
In the last five years, there have been many publications about this syndrome, with the identification of more than 50 families worldwide. It is important to both know and suspect this syndrome, because the diagnosis is easy, cheap and accessible (thyroid profile) and, although it has no specific treatment, early diagnosis prevents unnecessary testing and allows to offer genetic counseling to the families affected by it.
MCT8是甲状腺激素T4和T3的特异性转运体，可使它们进入大脑和其他器官。MCT8突变（艾伦-赫恩登-达德利综合征）会导致一种严重的X连锁精神运动发育迟缓，其特征是血浆T3升高而T4降低。
我们描述了西班牙诊断出的首例该综合征病例，并回顾了关于这一主题的已发表文献。我们既回顾了该综合征的各种临床表现、遗传学进展、鉴别诊断和治疗前景，又提出了一种诊断算法。
一名5岁男孩，临床表现与佩利措伊斯-梅茨巴赫病相符。PLP1基因测序未显示异常。进行的所有遗传和代谢研究均正常。最后，对甲状腺指标的全面研究揭示了与MCT8转运体缺乏一致的异常情况。SLC16A2基因（MCT8）测序显示外显子3存在突变，细胞水平的研究证实该突变改变了蛋白质的特性。
在过去五年中，关于该综合征有许多出版物，全球已鉴定出50多个家庭。了解并怀疑这种综合征很重要，因为诊断简单、便宜且可及（甲状腺指标），而且尽管它没有特异性治疗方法，但早期诊断可避免不必要的检查，并能为受其影响的家庭提供遗传咨询。
