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Aspartylglucosaminuria (AGU) is an inherited disease that is characterized by a decline in mental functioning, accompanied by an increase in skin, bone and joint issues. The disease is caused by a defect in an enzyme known as aspartylglucosaminidase. This enzyme plays a significant role in our bodies because it aids in breaking down certain sugars (for example, oligosaccharides) that are attached to specific proteins (for example, glycoproteins). Aspartylglucosaminuria itself is characterized as a lysosomal disease because it does deal with inadequate activity in an enzyme's function.〔()〕 Aspartylglucosaminidase functions to break down glycoproteins. These proteins are most abundant in the tissues of the body and in the surfaces of major organs, such as the liver, spleen, thyroid and nerves. When glycoproteins are not broken down, aspartylglucosaminidase backs up in the lysosomes along with other substances. This backup causes progressive damage to the tissues and organs.〔()〕 ==Signs and symptoms== At birth, there is no sign that a child will develop symptoms of aspartylglucosaminuria. Typically, signs and symptoms become apparent between two and four years of age and become progressively worse as the individual ages. The following signs and symptoms may appear:〔 * Individuals are more prone to respiratory infections * Development of scoliosis * Seizures or difficulty with movement * Skin and joints may become loose * Facial features change progressively; this may include: ::::# thickening of the skin ::::# features becoming more prominent ::::# large head ::::# broad lower jaw ::::# short, broad nose ::::# rounded cheeks〔 * Progression of developmental and mental disabilities, including: ::::# progressive loss of speech ::::# decrease in mental functioning ::::# before school age, concentration lowers ::::# development continues, but becomes slower than usual〔 * An intellectual peak occurs in the mid-teens and allows a plateau for the disease. Once an individual hits the age of 25-30 the decrease begins again, including: ::::# learned skills become lost which result in severe learning disabilities ::::# motor skills deteriorate ::::# individuals become less mobile and more dependent (Children are physically uncoordinated, but remain able to play sports and do everyday activities until they reach adulthood.) * During the first year of life inguinal and umbilical hernias are common. * Less severe symptoms include: ::::# enlargement of the spleen and liver ::::# diarrhea * People with aspartylglucosaminuria may have lower than average height, because they tend to go through puberty earlier. * Epilepsy may develop in adulthood. * Finnish studies have shown that life expectancy is shorter than average.〔()〕 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「Aspartylglucosaminuria」の詳細全文を読む スポンサード リンク
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