—galactosemic, adj./geuh lak'teuh see"mee euh/, n. Pathol.an inherited disorder characterized by the inability to metabolize galactose and requiring a galactose-free diet to avoid consequent mental retardation and eye, spleen, and liver abnormalities.[1930-35; GALACTOSE + -EMIA]
* * *a hereditary defect in the metabolism of the sugar galactose, which is a constituent of lactose, the main carbohydrate of milk. Infants with this condition appear normal at birth, but, after a few days of milk feeding, they begin to vomit, become lethargic, fail to gain weight, and show an enlargement of the liver. Untreated infants who survive are usually malnourished and stunted in growth; cataracts in the eyes and mental retardation may also occur. When their urine is tested for sugars, galactose invariably is present. In all affected infants, the symptoms of galactosemia regress after milk and milk products are eliminated from their diet.Normally, galactose is metabolized in the body to glucose, each step in the metabolic pathway being carried out by a specific organic catalyst, or enzyme. In galactosemia, the enzyme that catalyzes the second step, converting galactose-1-phosphate to glucose-1-phosphate, is not active. As a result of this metabolic block, there is an accumulation of galactose-1-phosphate in body tissues, and this compound is believed to be the cause of the cataracts and liver damage. Galactose is present in the blood and urine of persons suffering from galactosemia, and there is decreased formation of glucose in the body, which may result in a lowering of the blood glucose level. The mental retardation that is sometimes observed in galactosemic children may be caused by the high galactose level, the low glucose level, or both. It has been estimated that hereditary intolerance to galactose occurs in approximately one in 18,000 infants.Galactosemia is transmitted by an autosomal recessive gene. Unaffected carriers of the trait who mate can expect, on the basis of chance, to have one galactosemic child, two children who are unaffected but are carriers, and one normal child for each four children born. Reliable and simple tests are available to detect carriers of galactosemia and galactosemic newborn infants. The condition can be detected before birth by collecting sample fluid from the amniotic sac. When a lactose–galactose-free diet is initiated early in infancy and maintained during the first three years of life, the development of liver disease, cataracts, and mental retardation may usually be prevented. In time, an increased tolerance to galactose may develop.
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См. также в других словарях:
Galactosemia — Classification and external resources Galactose ICD 10 E … Wikipedia
Galactosemia — Galactosa Clasificación y recursos externos CIE 10 E … Wikipedia Español
galactosemia — f. hemat. Presencia de galactosa en la sangre. ⊆ pediat. y genét. Alteración del metabolismo de los glúcidos heredada de forma autosómica recesiva y que está causada por la falta del enzima que transforma la galactosa en glucosa, lo que provoca… … Diccionario médico
galactosemia — galactosemia. См. галактоземия. (Источник: «Англо русский толковый словарь генетических терминов». Арефьев В.А., Лисовенко Л.А., Москва: Изд во ВНИРО, 1995 г.) … Молекулярная биология и генетика. Толковый словарь.
galactosemia — [gə lak΄tō sē′mē ə] n. [ GALACTOS(E) + EMIA] a congenital disease caused by the genetic lack of an enzyme needed to metabolize galactose into glucose and producing mental retardation, cataracts, and liver damage … English World dictionary
Galactosemia — A genetic metabolic disease in which there is a defect in the body s ability to use the sugar galactose. In classic galactosemia, the basic defect is a deficiency of the enzyme known as GALT (galactose 1 phosphate uridyl transferase). This causes … Medical dictionary
galactosemia — noun Date: 1934 a metabolic disorder that is inherited as an autosomal recessive trait and in which galactose accumulates in the blood due to deficiency of an enzyme catalyzing its conversion to glucose • galactosemic adjective … New Collegiate Dictionary
galactosemia — noun A genetic metabolic disorder characterized by an inability to metabolize galactose properly … Wiktionary
galactosemia — n. any of three genetic disorders characterized by defective galactose metabolism resulting in an accumulation of galactose in the bloodstream (Medicine) … English contemporary dictionary
galactosemia — ga·lac·tos·emia … English syllables