Biomaterial Database

Minimizing false positive diagnoses in newborn screening for galactosemia. 1992

D M Frazier, and E H Clemons, and H N Kirkman

Brain and Development Research Center, Chapel Hill, North Carolina.

Heat and humidity, rather than summertime heat alone, cause extensive loss of galactose-1-phosphate uridyltransferase activity in mailed blood spots and seem to account for false positive diagnoses of galactosemia. The spots are partially protected from the effects of atmospheric humidity if they are allowed to dry and then are sealed in a plastic freezer bag before being exposed to higher humidity. Conversely, extensive loss of transferase activity occurs if the samples are sealed in the bags before the spots are dry. The fluorescence from transferase activity can be monitored with greater sensitivity fluorometrically than visually. A simultaneous fluorometric determination of phosphoglucomutase activity reveals whether decreased transferase activity represents sample deterioration or galactosemia. Mg2+ and a sulfhydryl agent, such as dithiothreitol, are needed for activity of phosphoglucomutase, an enzyme in the sequence leading to the fluorescent substance (NADPH). They must be added in certain modifications of the assay.

UI	MeSH Term	Description	Entries
D007231	Infant, Newborn	An infant during the first 28 days after birth.	Neonate,Newborns,Infants, Newborn,Neonates,Newborn,Newborn Infant,Newborn Infants
D008274	Magnesium	A metallic element that has the atomic symbol Mg, atomic number 12, and atomic weight 24.31. It is important for the activity of many enzymes, especially those involved in OXIDATIVE PHOSPHORYLATION.
D009249	NADP	Nicotinamide adenine dinucleotide phosphate. A coenzyme composed of ribosylnicotinamide 5'-phosphate (NMN) coupled by pyrophosphate linkage to the 5'-phosphate adenosine 2',5'-bisphosphate. It serves as an electron carrier in a number of reactions, being alternately oxidized (NADP+) and reduced (NADPH). (Dorland, 27th ed)	Coenzyme II,Nicotinamide-Adenine Dinucleotide Phosphate,Triphosphopyridine Nucleotide,NADPH,Dinucleotide Phosphate, Nicotinamide-Adenine,Nicotinamide Adenine Dinucleotide Phosphate,Nucleotide, Triphosphopyridine,Phosphate, Nicotinamide-Adenine Dinucleotide
D004229	Dithiothreitol	A reagent commonly used in biochemical studies as a protective agent to prevent the oxidation of SH (thiol) groups and for reducing disulphides to dithiols.	Cleland Reagent,Cleland's Reagent,Sputolysin,Clelands Reagent,Reagent, Cleland,Reagent, Cleland's
D004795	Enzyme Stability	The extent to which an enzyme retains its structural conformation or its activity when subjected to storage, isolation, and purification or various other physical or chemical manipulations, including proteolytic enzymes and heat.	Enzyme Stabilities,Stabilities, Enzyme,Stability, Enzyme
D005189	False Positive Reactions	Positive test results in subjects who do not possess the attribute for which the test is conducted. The labeling of healthy persons as diseased when screening in the detection of disease. (Last, A Dictionary of Epidemiology, 2d ed)	False Positive Reaction,Positive Reaction, False,Positive Reactions, False,Reaction, False Positive,Reactions, False Positive
D005693	Galactosemias	A group of inherited enzyme deficiencies which feature elevations of GALACTOSE in the blood. This condition may be associated with deficiencies of GALACTOKINASE; UDPGLUCOSE-HEXOSE-1-PHOSPHATE URIDYLYLTRANSFERASE; or UDPGLUCOSE 4-EPIMERASE. The classic form is caused by UDPglucose-Hexose-1-Phosphate Uridylyltransferase deficiency, and presents in infancy with FAILURE TO THRIVE; VOMITING; and INTRACRANIAL HYPERTENSION. Affected individuals also may develop MENTAL RETARDATION; JAUNDICE; hepatosplenomegaly; ovarian failure (PRIMARY OVARIAN INSUFFICIENCY); and cataracts. (From Menkes, Textbook of Child Neurology, 5th ed, pp61-3)	Galactokinase Deficiency Disease,Galactose-1-Phosphate Uridyl-Transferase Deficiency Disease,UDPglucose 4-Epimerase Deficiency Disease,Classic Galactosemia,Deficiency Disease, Galactokinase,Deficiency Disease, Galactose-1-Phosphate Uridyl-Transferase,Deficiency Disease, UDP-Galactose-4-Epimerase,Deficiency Disease, UDPglucose 4-Epimerase,Epimerase Deficiency Galactosemia,GALE Deficiency,GALK Deficiency,GALT Deficiency,Galactokinase Deficiency,Galactose Epimerase Deficiency,Galactose-1-Phosphate Uridyltransferase Deficiency,Galactose-1-Phosphate Uridylyltransferase Deficiency,Galactosemia,Galactosemia 2,Galactosemia 3,Galactosemia III,Galactosemia, Classic,Hereditary Galactokinase Deficiency,UDP-Galactose-4-Epimerase Deficiency,UDP-Galactose-4-Epimerase Deficiency Disease,UDPGlucose Hexose-1-Phosphate Uridylyltransferase Deficiency,UTP Hexose-1-Phosphate Uridylyltransferase Deficiency,UTP-Hexose-1-Phosphate Uridylyltransferase Deficiency Disease,Classic Galactosemias,Deficiencies, GALE,Deficiencies, GALK,Deficiencies, GALT,Deficiencies, Galactokinase,Deficiencies, Galactose Epimerase,Deficiencies, Galactose-1-Phosphate Uridyltransferase,Deficiencies, Galactose-1-Phosphate Uridylyltransferase,Deficiencies, Hereditary Galactokinase,Deficiencies, UDP-Galactose-4-Epimerase,Deficiency Disease, Galactose 1 Phosphate Uridyl Transferase,Deficiency Disease, UDP Galactose 4 Epimerase,Deficiency Disease, UDPglucose 4 Epimerase,Deficiency Diseases, UDP-Galactose-4-Epimerase,Deficiency Galactosemia, Epimerase,Deficiency Galactosemias, Epimerase,Deficiency, GALE,Deficiency, GALK,Deficiency, GALT,Deficiency, Galactokinase,Deficiency, Galactose Epimerase,Deficiency, Galactose-1-Phosphate Uridyltransferase,Deficiency, Galactose-1-Phosphate Uridylyltransferase,Deficiency, Hereditary Galactokinase,Deficiency, UDP-Galactose-4-Epimerase,Epimerase Deficiency Galactosemias,GALE Deficiencies,GALK Deficiencies,GALT Deficiencies,Galactokinase Deficiencies,Galactokinase Deficiencies, Hereditary,Galactokinase Deficiency Diseases,Galactokinase Deficiency, Hereditary,Galactose 1 Phosphate Uridyl Transferase Deficiency Disease,Galactose 1 Phosphate Uridyltransferase Deficiency,Galactose 1 Phosphate Uridylyltransferase Deficiency,Galactose Epimerase Deficiencies,Galactose-1-Phosphate Uridyltransferase Deficiencies,Galactose-1-Phosphate Uridylyltransferase Deficiencies,Galactosemia 2s,Galactosemia 3s,Galactosemia IIIs,Galactosemia, Epimerase Deficiency,Galactosemias, Classic,Galactosemias, Epimerase Deficiency,Hereditary Galactokinase Deficiencies,UDP Galactose 4 Epimerase Deficiency,UDP Galactose 4 Epimerase Deficiency Disease,UDP-Galactose-4-Epimerase Deficiencies,UDP-Galactose-4-Epimerase Deficiency Diseases,UDPGlucose Hexose 1 Phosphate Uridylyltransferase Deficiency,UDPglucose 4 Epimerase Deficiency Disease,UTP Hexose 1 Phosphate Uridylyltransferase Deficiency,UTP Hexose 1 Phosphate Uridylyltransferase Deficiency Disease,Uridyltransferase Deficiencies, Galactose-1-Phosphate,Uridyltransferase Deficiency, Galactose-1-Phosphate,Uridylyltransferase Deficiencies, Galactose-1-Phosphate,Uridylyltransferase Deficiency, Galactose-1-Phosphate
D005694	UTP-Hexose-1-Phosphate Uridylyltransferase	An enzyme that catalyzes the synthesis of UDPgalactose from UTP and galactose-1-phosphate. It is present in low levels in fetal and infant liver, but increases with age, thereby enabling galactosemic infants who survive to develop the capacity to metabolize galactose. EC 2.7.7.10.	Galactosephosphate Uridylyltransferase,UDP Galactose Pyrophosphorylase,Galactose-1-Phosphate Uridyltransferase,Galactose 1 Phosphate Uridyltransferase,Galactose Pyrophosphorylase, UDP,Pyrophosphorylase, UDP Galactose,UTP Hexose 1 Phosphate Uridylyltransferase,Uridyltransferase, Galactose-1-Phosphate,Uridylyltransferase, Galactosephosphate,Uridylyltransferase, UTP-Hexose-1-Phosphate
D006358	Hot Temperature	Presence of warmth or heat or a temperature notably higher than an accustomed norm.	Heat,Hot Temperatures,Temperature, Hot,Temperatures, Hot
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man