ABSTRACT
We report a novel glucose-6-phosphate dehydrogenase (G6PD) mutation, which we propose to name G6PD Cincinnati (c.1037A > T, p.N346I), found in combination with G6PD Gastonia (c.637G > T, p.V213L) in an infant who presented with neonatal cholestasis. The G6PD Cincinnati mutation results in a non-conservative amino acid substitution at the tetramer interface disturbing its formation, as seen by native gel electrophoresis and immunoblotting. G6PD Gastonia disrupts dimerization of the enzyme and by itself causes chronic non-spherocytic hemolytic anemia. The G6PD Cincinnati mutation may have aggravated the clinical picture of G6PD Gastonia with the result of severe perinatal hemolysis causing cholestasis and associated liver injury.
Subject(s)
Cholestasis/etiology , Glucosephosphate Dehydrogenase Deficiency/genetics , Glucosephosphate Dehydrogenase/genetics , Hyperbilirubinemia, Neonatal/etiology , Mutation/genetics , Amino Acid Sequence , Amino Acid Substitution , Cholestasis/enzymology , Cholestasis/pathology , DNA/genetics , Glucosephosphate Dehydrogenase Deficiency/enzymology , Humans , Hyperbilirubinemia, Neonatal/enzymology , Hyperbilirubinemia, Neonatal/pathology , Infant, Newborn , Male , Molecular Sequence Data , Polymerase Chain Reaction , Sequence Homology, Amino AcidABSTRACT
Grade A raw milk which had initial psychrotrophic counts of less than 103/ml was inoculated with an antibiotic-resistant Pseudomonas sp. to a final cell concentration of 102, 104, or 106/ml. The inoculated milk was held at 4 C for 14 h and then exposed to the following time-temperature treatments: 72 C for 15 sec, 79 C for 15 sec, 88 C for 10 sec, and 95 C for < 5 sec. An uninoculated raw milk control was handled and analyzed along with inoculated samples. Aliquots of milk were analyzed for marked Pseudomonas sp., total psychrotrophic counts, numbers of Pseudomonas , and for distribution of nitrogen before and after each heat treatment and after storage of non-heat-treated raw milk and heat-treated samples for 7 and 14 days at 7 C. Psychrotrophic counts were significantly affected by heat treatment, initial cell inoculum, days stored, and plating media. Non-casein N, non-casein protein, total albumin, ß-lactoglobulin, proteose-peptone, and globulin N were significantly decreased by heat treatment. Non-casein N, non-casein protein, ß-lactoglobulin, and proteose-peptone were significantly increased by days of storage.
