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Miller–Dieker syndrome (abbreviated MDS), Miller–Dieker lissencephaly syndrome (MDLS), and chromosome 17p13.3 deletion syndrome) is a micro deletion syndrome characterized by congenital malformations (a physical defect detectable in an infant at birth which can involve many different parts of the body including the brain, hearts, lungs, liver, bones, or intestinal tract). In this case, it is usually mainly the brain being affected. The congenital malformation can be genetic random and of unknown origin. The malformation is in fact characterized by lissencephaly (smooth brain). MDS is a contiguous gene syndrome, as well, which is a disorder due to the deletion of multiple gene loci that are adjacent to one another. The disorder arises from the deletion of part of the small arm of chromosome 17p (which includes both the ''LIS1'' and ''14-3-3 epsilon'' genes), leading to partial monosomy. There may be unbalanced translocations (i.e. 17q:17p or 12q:17p), or the presence of a ring chromosome 17. This syndrome should not be confused with Miller syndrome, an unrelated rare genetic disorder, or Miller Fisher syndrome, a form of Guillain-Barré syndrome. ==Early detection== With the use of prenatal ultrasonographic imaging, early detection of abnormal brain development in the fetus with MDS can be seen. At birth, facial dysmorphism can be present in the infant. Young children, when affected, can suffer from feeding difficulties, severe intellectual disability, developmental delay, and seizures. An early way to detect this syndrome in children can be by brain MRI which can show the image of smooth brain, also called lissencephaly. Children with this syndrome may remain underdiagnosed because of how rare it is, and how common it is to have facial features that appear to be dysmorphic. They are highly variable and not easily recognizable because this syndrome shares distinct external features (phenotype) similar to more common syndromes. Lack of relevant family history can also prevent suspicion in many cases. FDNA provides a service that in turn increases the chances of detecting these distinct characteristics, which, when shown to a geneticist, can assist in reaching the right medical diagnosis. If a couple has had one child with MDS, they can be offered prenatal diagnosis in future pregnancies. This option is particularly important for the 20% of MDS families where one parent carries a balanced chromosome rearrangement. The risk for these couples to have another affected child depends on the exact type of chromosome rearrangement present and may be as high as 25-33%. For families in which both parents' chromosomes are normal, the risk of having another child with MDS is low (1% or less). Either chorionic villus sampling (CVS) or amniocentesis can be used early in a pregnancy to obtain a small sample of cells from the developing embryo for chromosome studies. Early prenatal diagnosis by ultrasound is not reliable because the brain is normally smooth until later in pregnancy. Couples who are considering prenatal diagnosis should discuss the risks and benefits of this type of testing with a geneticist or genetic counselor. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Miller–Dieker syndrome」の詳細全文を読む スポンサード リンク
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