- An insufficient quantity of some substance (as in dietary d. or hemoglobin d. in marrow aplasia); organization (as in mental d.); activity (as in enzyme d. or reduced oxygen-carrying capacity of the blood), etc., of which the amount present is of normal quality. SEE ALSO: d. disease. [L. deficio, to fail, fr. facio, to do]- adult lactase d. onset of lactase d., with resulting milk intolerance and malabsorption, in adulthood. Inherited forms may not be manifested until adulthood; any process that damages the intestinal lining cells can cause lactase d. in adults.- antitrypsin d. d. of α1-antitrypsin, a serum protease inhibitor (PI), is associated with emphysema and/or liver cirrhosis. By isoelectric focusing, numerous variants have been identified, with different levels of normal activity; autosomal recessive inheritance, caused by mutation in the P1 gene on chromosomal 14q.- α1-antitrypsin d. absence of a serum proteinase inhibitor that may cause relapsing nodular nonsuppurative panniculitis.- arch length d. the difference between the available circumference of the dental arch and that required to accommodate the succedaneous teeth in proper alignment.- arginosuccinate lyase d. SYN: argininosuccinic aciduria.- biotinidase d. a rare, autosomal recessive disease causing loss of excessive biotin; clinical manifestations may be absent, but extreme manifestations include seizures, alopecia, dermatitis, hypotonia, optic atrophy, ataxia, developmental delay, hearing deficits, and occasionally immunodeficiency; trait has a prevalence of 1 in 60,000.- carnitine d. a condition associated with many disorders of fatty acid oxidation. Fatty acids are linked to carnitine as they are transported across the inner mitochondrial membrane; errors in this process lead to problems with energy production; patients may experience episodes of hypoglycemia or metabolic acidosis and may have cardiomyopathy or skeletal muscle weakness.- galactokinase d. [MIM*230200] an inborn error of metabolism due to congenital d. of galactokinase (GALK), resulting in increased blood galactose concentration (galactosemia), cataracts, hepatomegaly, and mental d.; autosomal recessive inheritance, caused by mutation in the GALK gene on 17q. Galactose epimerase d. [MIM*230350] and galactose-1-phosphate uridyl transferase d. [MIM*230400] produce much the same clinical picture.- glucose-6-phosphate dehydrogenase d. a d. of glucose-6-phosphate dehydrogenase, an enzyme important for maintaining cellular concentrations of reduced nucleotides. An X-linked disorder with various polymorphic forms, it can cause a variety of anemias including favism, primaquine sensitivity and other drug sensitivity anemias, anemia of the newborn, and chronic nonspherocytic hemolytic anemia.- glucosephosphate isomerase d. [MIM*172400] an enzyme d. characterized by chronic nonspherocytic hemolytic anemia; autosomal recessive inheritance. SYN: phosphohexose isomerase d..- β-d-glucuronidase d. a rare d. of β-d-glucuronidase; an autosomal recessive disorder with several allelic forms, characterized by abnormal mucopolysaccharide metabolism leading to progressive mental deterioration, splenic and hepatic enlargement, and dysostosis multiplex. SYN: mucopolysaccharidase.- glutathione synthetase d. an inborn error of metabolism associated with massive urinary excretion of 5-oxyproline, elevated levels of 5-oxyproline in the blood and cerebrospinal fluid, severe metabolic acidosis, tendency toward hemolysis, and defective central nervous systems function. Glutathione synthetase d. has been reported as a generalized condition or with a d. restricted to erythrocytes.- 11-hydroxylase d. a type of congenital adrenal hyperplasia, with multiple manifestations, including hypertensive types and salt-wasting varieties.- 21-hydroxylase d. one form of congenital adrenal hyperplasia, with variable presentations, including simple virilizing, salt-wasting, or nonclassic types.- hypoxanthine guanine phosphoribosyltransferase d. a sex-linked inherited metabolic disorder; complete d. results in Lesch-Nyhan syndrome; incomplete d. is associated with acute gouty arthritis and renal stones.- immunologic d. SYN: immunodeficiency.- LCAT d. a rare condition characterized by corneal opacities, hemolytic anemia, proteinuria, renal insufficiency, and premature atherosclerosis, and very low levels of lecithin cholesterol acyltransferase (LCAT) activity; results in accumulation of unesterfied cholesterol in plasma and tissues.- leukocyte adhesion d. (LAD) an inherited disorder (autosomal recessive) in which there is a defective CD18 adherence complex that disturbs chemotaxis. It is characterized by recurrent bacterial pyogenic infections and impaired wound healing.- long-chain 3-hydroxyacyl-CoA dehydrogenase d. a fatty acid oxidation disorder; patients may experience episodes of acute hypoketotic hypoglycemia (similar to that found in MCAD d.), cardiomyopathy, muscle weakness, and liver abnormalities.- long-chain/very long-chain acyl-CoA dehydrogenase d. a disorder of fatty acid oxidation in patients who lack the enzyme very long chain acyl-CoA dehydrogenase; sometimes manifested as weakness, hypotonia, cardiomyopathy, rhabdomyolysis, and episodes of hypoglycemia during fasting.- medium-chain acyl-CoA dehydrogenase d. the most common fatty acid oxidation disorder, presenting as acute episodes triggered by prolonged fasting for more than 12–16 hours, with hypoglycemia, vomiting, and lethargy, which may progress to seizures, coma, or cardiopulmonary collapse, usually presenting before age 3.- muscle phosphorylase d. type V glycogen storage disease, affecting muscle, caused by d. of muscle phosphorylase.- placental sulfatase d. an enzyme defect in the placenta which results in failure of conversion of 16α-hydroxydehydroepiandrosterone to estriol; women with this condition rarely enter into spontaneous labor.- primary carnitine d. a rare defect in carnitine metabolism due to a defect in carnitine transport; patients may present with hypoketotic hypoglycemia and develop cardiomyopathy or skeletal muscle weakness.- proximal femoral focal d. (PFFD) a congenital defect in which variable portions of the upper end of the femur are reduced or absent.- pseudocholinesterase d. [MIM*177400] an autosomal dominant disorder manifested by exaggerated responses to drugs ordinarily hydrolyzed by serum pseudocholinesterase ( e.g., succinylcholine); believed to entail production of a variant enzyme that is less active than the normal enzyme in hydrolyzing appropriate substrates, but also abnormally resistant to the effects of anticholinesterases, caused by mutation in the pseudocholinesterase E1 gene (CHE1) on 3q.- pyruvate kinase d. [MIM*266200] a disorder in which there is a d. of pyruvate kinase in red blood cells; characterized by hemolytic anemia varying in degree from one patient to another; autosomal recessive inheritance, caused by mutation in the pyruvate kinase liver and red blood cell gene (PKLR) on chromosome 1q.- riboflavin d. ariboflavinosis.- secondary antibody d. SYN: secondary immunodeficiency.- short-chain acyl-CoA dehydrogenase d. a disorder of fatty acid oxidation; patients may have chronic acidosis, failure to thrive, muscle weakness, and developmental delay.- taste d. [MIM*171200] reduced or absent ability to detect a bitter taste in a group of compounds of which phenylthiocarbamide is the prototype, due to the homozygous state of a common allele. SEE ALSO: phenylthiourea.
* * *1) a shortage of substances (as vitamins) necessary to health2) DELETION
* * *n.
* * *de·fi·cien·cy (de-fishґən-se) less than the normal amount of something; see also defect. For deficiencies of specific, individual enzymes, see under the enzyme name.
Medical dictionary. 2011.