Lack of functional Fragile X mental retardation protein (FMRP) is the pri-mary cause of the Fragile-mental retardation syndrome in humans. In most
cases, the disease results from transcriptional silencing of fragile mental
retardation gene 1, fmr1, which encodes FMRP. However, a single mis-sense mutation (I304N) in the second KH domain of FMRP gives rise to a
particularly severe case of Fragile X syndrome.
Di truyền gene trội liên kết nhiễm sắc thể X
Ngoại trừ trường hợp hội chứng NST X dễ gãy (fragile X syndrome), các bệnh di truyền gene trội liên kết NST X có số lượng ít hơn và có ý nghĩa về mặt lâm sàng không bằng trường hợp di truyền gene lặn liên kết NST X.
Phả hệ minh họa sự di truyền của một gene trội liên kết NST X, X1 là allele bình thường; X2 là allele bệnh.
Fragile X mental retardation protein (FMRP) is an RNA binding protein
necessary for correct spatiotemporal control of neuronal gene expression in
humans. Lack of functional FMRP causes fragile X mental retardation,
which is the most common inherited neurodevelopmental disorder in
American men face a staggering array of health concerns. According
to the Centers for Disease Control and Prevention, 70 percent of
American men are overweight, a key predictor of future health problems.
Almost 25 percent smoke, another key risk factor. One in five
American men has heart disease, and 29 percent aged twenty and
older suffer from hypertension. More than 11 percent of men face a
limitation in their usual activities due to chronic health conditions.
In addition, the medical concerns men face often differ from those of
most concern to women.
Huang, Yen and Lu (Chapter 18) review the role of SPECT in the diagnosis of
idiopathic Parkinson’s disease and its differentiation from other conditions
characterised by parkinsonisms such as dementia with Lewy Bodies (DLB) and
vascular parkinsonism. Accurate diagnosis is clearly critical for treatment and
prognosis, and the authors provide a very useful overview of recent developments in
dopamine transporter imaging which have led to important advances in this area.
A series of relatively short (GCC)ntriplet repeats (n¼3–30) located within
regulatory regions of many mammalian genes may be considered as puta-tive cis-acting transcriptional elements (GCC-elements). Fragile X-mental
retardation syndrome is caused by an expansion of (GCC)ntriplet repeats
within the 5¢-untranslated region of the human fragile X-mental retarda-tion 1 (FMR1) gene.