deficiency
(di-fĭsh'ĕn-sē 
)
[L. deficere, to lack]
Less than the normal amount; a lack.
deficient,
(di-fĭsh'ĕnt)
adj.acid lipase d.Either of two autosomal recessive illnesses (Wolman disease and cholesterol ester storage disease) in which the body lacks an enzyme for metabolizing fats, causing cholesterol, oils, or waxes to accumulate in abnormal amounts in the body. SYN: acid lipase disease.
SEE: Wolman disease.
antithrombin-III d.An inherited hypercoagulable deficiency that is a common cause of deep venous thrombosis or pulmonary embolism. It is caused by absent or deficient levels of antithrombin III in the blood. SYN: hereditary thrombophilia.
arginase d.A rare autosomal recessive neurodegenerative disease of infancy and childhood in which a deficiency of arginase results in faulty urea cycle metabolism and hyperammonemia.
aspartoacylase d.Canavan disease.
biotinidase d.An autosomal recessive disease in which affected children fail to metabolize biotin effectively. Seizures, encephalopathy, neurodevelopmental delay, spasticity or diminished muscle tone, paresis, visual disturbances, deafness, skin rash, and hair loss commonly occur. Immediate ongoing treatment with supplemental biotin can effectively suppress the symptoms of this disease.
branching enzyme d.Type IV glycogen storage disease.
SEE: color blindness.
SEE: color blindness.
copper d.The clinical consequences of inadequate consumption or absorption of dietary copper. Its hallmarks include an unsteady gait, neuropathy, muscle spasticity, and , occasionally, anemia. It may occur as a consequence of gastric bypass surgery or long-term parenteral nutrition.
delta storage pool d.Hermansky-Pudlak syndrome.
factor VII d.A rare autosomal recessive bleeding disorder in which levels of coagulation factor VII are deficient.
Laboratory tests suggesting the bleeding diathesis include an activated partial thromboplastin time (aPTT) test, prothrombin time (PT) test, and thrombin time (TT) test. Diagnosis is confirmed with a factor VII assay.
As in any form of hemophilia, spontaneous or easily provoked bleeding is the primary symptom. People with less than 1% of normal factor VII activity bleed into joint spaces (hemarthroses). Spontaneous nosebleeds, upper and lower GI bleeding, heavy menstrual bleeding, and urinary tract bleeding can occur. Life-threatening internal bleeding after trauma is common.
Recombinant factor VII or prothrombin complex concentrates are the primary medical treatments. Fresh frozen plasma contains factor VII and can be used in emergencies when primary treatments are unavailable.
Patients should be educated to avoid contact sports or potentially hazardous recreational or occupational activities that might contribute to bleeding, e.g., motorcycle riding, working at heights, and using hazardous tools such as band saws or chain saws. Bleeding that is not easily controlled by directly applied pressure should prompt patients to seek emergency care.
factor XI d.An autosomal, recessively inherited decrease in coagulation factor XI that results in a reduced risk for blood clotting, e.g., deep venous thrombosis or pulmonary embolism.
functional iron d.A deficiency of iron significant enough to affect the development of healthy red blood cells. It may precede the appearance of measurable anemia.
Treatments include iron and folate supplements and epoetin alpha (Procrit) to increase red blood cell production. In emergencies, infusion of fresh frozen packed cells or washed packed cells provide temporary relief.
Functional iron deficiency may be defined by the presence of hypochromatic red cells; by an increase in hemoglobin production after test doses of administered iron; or, most accurately, by the measurement of the mean hemoglobin content of reticulocytes. It is common in patients receiving hemodialysis and in critically ill persons.
glucose-6-phosphate dehydrogenase d.An X-linked disorder that produces nonimmune hemolytic anemia.
In the U.S. this enzyme disorder is present in about 13% of African-American (AA) males and 2% of AA females. The deficiency also occurs in Arab, Mediterranean, and Asian populations. Worldwide, 400 million people are estimated to be deficient in the enzyme. The highest prevalence of the disease is in sub-Saharan Africa.
The disease is caused by a substitution of one nucleotide in the gene that codes for glucose-6-phosphate dehydrogenase (G6PD) or insufficient production of G6PD. More than 140 variants in the gene have been identified, along with more than 400 phenotypes, some of which have very little enzymatic activity, some relatively more. The severity of the presenting signs and symptoms depends on the genetic variation.
SEE: glucose-6-phosphate dehydrogenase; nicotinamide adenine dinucleotide phosphate.
When G6PD deficiency is present at birth, neonatal jaundice may occur. Acute hemolytic anemia may occur with exposure to certain stressors, with accompanying darkening of urine as a result of hemoglobinuria, and jaundice as a result of the deposition of bilirubin in the skin. Most people with genetic variants of G6PD are asymptomatic throughout their lives and experience no complications without exposure to specific stressors. Jaundice may be esp. severe in patients who have other hemolytic anemias or defects in bilirubin metabolism, such as Gilbert syndrome or thalassemias.
G6PD deficiency should be suspected when an individual develops acute hemolytic anemia after exposure to a drug that is known to place oxidative stress on cells, after a major illness or physiological stress, e.g., strenuous or prolonged exercise, or after consuming fava beans (Vicia faba), a legume that contains biologically active chemicals that increase the activity of the hexose monophosphate shunt. Drugs clearly associated with G6PD hemolysis include sulfonamides, dapsone, nitrofurantoin, and primaquine. Infectious causes include infection with hepatitis A or B, cytomegalovirus, and Salmonella typhi. Patients with chronic red blood cell breakdown caused by G6PD deficiency may develop gallstones and splenomegaly. Laboratory tests for evidence of the enzyme deficiency are available.
After diagnosis, patients with G6PD should avoid known triggers of hemolysis. During hemolytic crises, e.g., in neonatal jaundice, affected infants are treated with ultraviolet phototherapy to reduce unconjugated bilirubin in the plasma and prevent kernicterus. Adults with hemolytic crises may require acute or periodic blood transfusions.
Patients with G6PD deficiency should be made aware of their diagnosis and should carry or be able to access lists of drugs that they should avoid. Many patients have ongoing hemolysis. They should be advised to have regular blood tests to see if their hemoglobin levels are stable or dropping and to determine if they require regularly scheduled transfusions, medications for iron overload (after receiving numerous transfusions), or special precautions when they travel. (They may not be able to use some prophylactic antimalarial drugs or antibiotics safely.)
glycogen branching enzyme d.Adult polyglucosan body disease.
ABBR: ISD
Weakening of the urethral sphincter muscles, a frequent cause of stress urinary incontinence.ABBR: LAD
A rare autosomal recessive disorder in which white blood cells are unable to migrate out of blood vessels in response to infection. It often presents in early childhood with severe periodontal disease, premature loss of teeth, and recurrent infections.lysosomal acid lipase d.Wolman disease.
medium-chain acyl-CoA dehydrogenase d.
ABBR: MCADD
An inherited disorder of faulty nutrient oxidation in which affected infants are unable to metabolize fatty acids when their stores of blood glucose are low, e.g., between meals. The disease is common, occurring in 1 in 10,000 infants, and often fatal in infancy. Surviving infants may suffer brain damage from inadequate nutrition to the central nervous system during fasts.SEE: mental retardation.
muscle phosphorylase d.McArdle disease.
ornithine transcarbamylase d.The most common urea cycle enzyme deficiency disorder inherited as an autosomal recessive trait and characterized by the absence of ornithine transcarbamylase (an enzyme in the urea cycle), which results in the excessive buildup of ammonia in the bloodstream. The disease is typically diagnosed in infancy and occurs in less than 1 in 8000 births.
ABBR: PFKM
A glycogen storage disease caused by a deficiency of muscle phosphofructokinase and characterized by muscular weakness, muscle cramps after exercise, hemolysis, hyperuricemia, and myoglobinuria. SYN: glycogen storage disease type VII; Tarui disease.phytanoyl-CoA hydroxylase d.Refsum disease.
signal transducer and activator of transcription 3 d.
ZAP–70 d.Zeta-chain associated protein kinase 70 kDa, a severe combined immunodeficiency disease in which CD8+ T cells are missing from the circulation and the thymus develops abnormally.