Dihydropteridine reductase activity in eluates from dried blood spots: Automation of an assay for a national screening service

Surplice, I. M.; Griffiths, Paul; Green, A.; Leeming, R. J.

doi:10.1007/bf01799682

Cited by 11 publications

(8 citation statements)

References 8 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Most previous studies did not consider adjustments for hemoglobin concentrations, but rather expressed the enzyme activity per unit volume of blood. Surplice et al used hemoglobin adjustment, which improved assay precision and compensated for the effect of age on hematocrit (Surplice et al 1990). A similar finding was observed in this study.…”

Section: Effect Of Sample Amounts and Incubation Timesupporting

confidence: 91%

“…Several enzyme assays that use dried blood spots (DBSs) have been developed to screen for inherited metabolic disorders (Chamoles et al 2001a;2002a, b;2001b;Li et al 2004;Surplice et al 1990;Wang et al 2005;Wang et al 2007;Zhang et al 2008). These strategies have some advantages over those using whole blood samples, in that there is no need for additional sampling and prompt second-tier tests are available without delay for newborns showing abnormal screening results.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Newborn screening for galactosemia by a second‐tier multiplex enzyme assay using UPLC‐MS/MS in dried blood spots

Jun

Park

et al. 2011

J of Inher Metab Disea

View full text Add to dashboard Cite

Galactosemia is one of the most important inherited metabolic disorders detected by newborn screening tests. Abnormal results during screening should be confirmed by enzyme activity assays. Recently, we developed a multiplex enzyme assay for galactosemia in erythrocytes using ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). In this study, we proposed a second-tier multiplex enzyme assay for galactosemia that can be directly applied to dried blood spots (DBSs). Supernatants from two rehydrated-punched 3.2-mm DBSs were incubated with a reaction mixture containing [¹³C6]galactose, [¹³C2]galactose-1-phosphate, and UDP-glucose as substrates for three galactose-metabolizing enzymes. After a 4-hour incubation, the end products from the combined reaction mixture, [¹³C6]galactose-1-phosphate, UDP-[¹³C2]galactose, and UDP-galactose, were simultaneously measured using UPLC-MS/MS. Substrates, products, and internal standards from the mixture of the three enzyme reactions were clearly separated in the UPLC-MS/MS system, with an injection cycle time of 10 min. Intra- and inter-assay imprecisions of the UPLC-MS/MS were 8.4-14.8% and 13.2-15.7% CV, respectively. Enzyme activities in DBSs from 37 normal individuals and 10 patients with enzyme deficiencies were analyzed. DBSs from galactosemia patients showed consistently lower enzyme activities as compared to those of normal individuals. In conclusion, multiplex enzyme assays using UPLC-MS/MS can be successfully applied to DBS analysis. This method allows a fast and effective second-tier test for newborns showing abnormal screening results.

show abstract

Section: Effect Of Sample Amounts and Incubation Timesupporting

confidence: 91%

Section: Introductionmentioning

confidence: 99%

Newborn screening for galactosemia by a second‐tier multiplex enzyme assay using UPLC‐MS/MS in dried blood spots

Jun

Park

et al. 2011

J of Inher Metab Disea

View full text Add to dashboard Cite

show abstract

“…The enzyme in dried blood spots is stable enough for the sample to be mailed to a central laboratory, where the assay can be automated. 75 DHPR activity has been also detected in other cells, including leukocytes, 76 lymphocytes, 77 platelets, 41,42 cultured fibroblasts, 18 and amniocytes, 78 with more laborious and timeconsuming methods. As expected, heterozygotes display about half normal enzyme activity, with only few exceptions, which display a much lower value and are possibly because of dominant negative mutations or to negative allelic complementation.…”

Section: Enzyme Activitymentioning

confidence: 97%

Dihydropteridine reductase deficiency in man: From biology to treatment

Ponzone

Spada

Ferraris

et al. 2003

Medicinal Research Reviews

View full text Add to dashboard Cite

In 1975, dihydropteridine reductase (DHPR) deficiency was first recognized as a cause of tetrahydrobiopterin (BH(4)) deficiency, leading to hyperphenylalaninemia (HPA) and impaired biogenic amine deficiency. So far, more than 150 patients scattered worldwide have been reported and major progresses have been made in the understanding of physiopathology, screening, diagnosis, treatment, and molecular genetics of this inherited disease. Present knowledge on different aspects of DHPR deficiency, largely derived from authors' personal experience, is traced in this article.

show abstract

“…Ninety-eight per cent of those detected suffer from a deficiency ofthe enzyme phenylalanine hydroxylase. The remaining 2% suffer from BH4 deficiency, including dihydropteridine reductase (DHPR) deficiency (Surplice et al 1990). Jardim et al (1994) reported that HP As are among the best-knovvn inborn errors of metabolism because of the relatively high frequency of HPAs in this group of diseases, the ease with which HPAs can be diagnosed and the efficient treatment which can be achieved if HPAs are diagnosed early.…”

Section: Pogson • Dihydropteridine Reductase Deficiencymentioning

confidence: 99%

“…Dried blood spots can be analysed for DHPR deficiency in neonatal screening for PKU, and Surplice et al (1990) have pointed out that the UK neonatal screening programme detects virtually all neonates with HPA. In all cases where HPA has been identified via this screening process, the possibility of a defect in BH4 metabolism should be considered (Hyland 1993).…”

Section: Diagnosismentioning

confidence: 99%

Issues for consideration in dihydropteridine reductase (DHPR) deficiency: a variant form of hyperphenylalaninaemia

Pogson¹

1997

J Intellect Disabil Res

View full text Add to dashboard Cite

An adult male with intellectual disabilities demonstrated deterioration in many skills over a number of years and an increase in his temper outbursts was also reported. At 18 years of age, he had been diagnosed as having dihydropteridine reductase (DHPR) deficiency, but treatment had proved unsuccessful in the short term and was discontinued. Dihydropteridine reductase deficiency is a recessively inherited disorder of the amino acid metabolism resulting in a deficiency of tetrahydrobiopterin, an essential cofactor for phenylalanine, tyrosine and tryptophan metabolism. This causes a severe deficiency of neurotransmitters in the brain. Following further neurological examinations, treatment for the subject was recommenced at the age of 30 years. Few reports of late-diagnosis DHPR have been documented. This paper outlines one case report of DHPR, highlighting the importance of diagnosis, medical treatment and nursing care.

show abstract

Dihydropteridine reductase activity in eluates from dried blood spots: Automation of an assay for a national screening service

Cited by 11 publications

References 8 publications

Newborn screening for galactosemia by a second‐tier multiplex enzyme assay using UPLC‐MS/MS in dried blood spots

Newborn screening for galactosemia by a second‐tier multiplex enzyme assay using UPLC‐MS/MS in dried blood spots

Dihydropteridine reductase deficiency in man: From biology to treatment

Issues for consideration in dihydropteridine reductase (DHPR) deficiency: a variant form of hyperphenylalaninaemia

Contact Info

Product

Resources

About