Hyperphenylalaninemia Due to Dihydropteridine Reductase Deficiency: Diagnosis by Measurement of Oxidized and Reduced Pterins in Urine

PEDIATRICS ◽  
1980 ◽  
Vol 65 (4) ◽  
pp. 806-810
Author(s):  
Sheldon Milstien ◽  
Seymour Kaufman ◽  
George K. Summer
Keyword(s):  
High Performance ◽  
Active Form ◽  
High Performance Liquid Chromatographic ◽  
Dihydropteridine Reductase ◽  
Normal Children ◽  
Reductase Deficiency ◽  
Cultured Skin ◽  
Aromatic Amino Acid Hydroxylase ◽  
Liver Biopsies ◽  
Liquid Chromatographic

Hyperphenylalaninemia due to dihydropteridine reductase deficiency results from the inability to maintain the aromatic amino acid hydroxylase cofactor, tetrahydrobiopterin, in its reduced or active form. Diagnosis of the disease is usually made by direct enzymatic assay on liver biopsies or in cultured skin fibroblasts. Evidence is presented that normal children and classic phenylketonuric children excrete mainly tetrahy-drobiopterin in their urmnes, whereas children with dihydropteridine reductase deficiency excrete only oxidized forms of biopterin. Details of a rapid high performance liquid chromatographic assay for the measurement of the various forms of biopterin in urine are presented. This assay can be used to screen for suspected dihydropteridine reductase mutants.

Blood Serotonin Levels in Adults, Autistic and Non-Autistic Children—With a Comparison of Different Methodologies

1987 ◽  
Vol 24 (6) ◽  
pp. 625-634 ◽  
Author(s):  
N R Badcock ◽  
J G Spence ◽  
L M Stern
Keyword(s):  
High Performance ◽  
High Performance Liquid Chromatographic ◽  
Serotonin Level ◽  
Autistic Children ◽  
Normal Children ◽  
Blood Serotonin ◽  
Normal Ranges ◽  
Significant Difference ◽  
Assay Methods ◽  
Liquid Chromatographic

Recent interest in conditions associated with increased blood serotonin level has highlighted the need for consistency between assay methods to allow for more accurate delineation of serotinin variables. To this end, comparison was made between a spectrofluorimetric technique frequently used in the past and two potentially more specific high performance liquid chromatographic procedures. Normal ranges and diurnal variations for blood serotonin in adults, normal, autistic children and children with developmental dysphasia were also determined. No significant difference was found between serotonin level in blood drawn by simultaneous venepuncture and capillary (fingerprick) collection. Whilst there was no evidence of circadian rhythm, seasonal variation with mean blood serotonin levels significantly lower in summer than in two successive winters was suggested. Blood serotonin values in normal children tended to decline with increasing age. No similar maturational effect was apparent in autistic children. The mean level for autistic children in winter was significantly higher than that for normal children in the same season; despite this there was considerable overlap of blood serotonin levels between normal and autistic groups. Serotonin levels determined by the three different methodologies showed a high correlation but differed significantly: caution should be exercised when comparing blood serotonin results where different methods are employed.

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