Monitoring of therapy in tyrosinemia type I: Quantification of nitisinone in dried blood spots

Abstract Background: Hereditary tyrosinemia type I (HT) fulfills the criteria for inclusion in neonatal screening programs, but measurement of tyrosine lacks clinical specificity and quantitative assay of succinylacetone is laborious. We developed a semiquantitative assay based on inhibition of δ-aminolevulinate dehydratase (ALA-D) by succinylacetone. Methods: Preincubation of 3-mm discs from dried-blood spots and reaction of the enzyme with δ-aminolevulinic acid as substrate were performed in microtiter plates. After separation of the supernatant and 10 min of color reaction with modified Ehrlich reagent, the formation of porphobilinogen was measured at 550 nm in a plate reader. Results: The detection limit for succinylacetone was 0.3 μmol/L; imprecision (CV) was <5.5% within-run and 10–16% between-run. Storage of blood spots at ambient temperature for several days led to a significant decrease of ALA-D activity. Enzyme activity was lost in filter cards at 45 °C, but remained stable at 2–37 °C. Enzyme activity was decreased in EDTA blood. The absorbance at 550 nm was 0.221 (± 0.073) in healthy neonates and 0.043–0.100 in 11 patients with HT. All neonates with increased tyrosine (above the 99.5th centile) in neonatal screening (97 of 47 000) had normal results by the new assay. Conclusions: The spectrophotometric microassay for ALA-D is a simple and sensitive test for HT. This represents a basis for further examination of its general reliability as a confirmatory test if tyrosine is found to be increased.

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Quantitative determination of succinylacetone in dried blood spots for newborn screening of tyrosinemia type I

Molecular Genetics and Metabolism ◽

10.1016/j.ymgme.2005.12.005 ◽

2006 ◽

Vol 88 (1) ◽

pp. 16-21 ◽

Cited By ~ 47

Author(s):

Mark J. Magera ◽

Nishantha D. Gunawardena ◽

Si Houn Hahn ◽

Silvia Tortorelli ◽

Grant A. Mitchell ◽

...

Keyword(s):

Quantitative Determination ◽

Newborn Screening ◽

Dried Blood Spots ◽

Type I ◽

Blood Spots ◽

Tyrosinemia Type I

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Preliminary Proficiency Testing Results for Succinylacetone in Dried Blood Spots for Newborn Screening for Tyrosinemia Type I

Clinical Chemistry ◽

10.1373/clinchem.2009.133819 ◽

2009 ◽

Vol 55 (12) ◽

pp. 2207-2213 ◽

Cited By ~ 12

Author(s):

Barbara W Adam ◽

Timothy H Lim ◽

Elizabeth M Hall ◽

W Harry Hannon

Keyword(s):

Newborn Screening ◽

Proficiency Testing ◽

False Negative ◽

Dried Blood Spots ◽

Screening Tests ◽

Type I ◽

Primary Metabolite ◽

Screening Practices ◽

Tyrosinemia Type I ◽

Stable Performance

Abstract Background: Succinylacetone (SUAC) is the primary metabolite accumulated in tyrosinemia type I—an inborn error of metabolism that, if untreated, can cause death from liver failure during the first months of life. Newborn screening laboratories measure SUAC in dried blood spot (DBS) samples to detect asymptomatic tyrosinemia type I. We used panels of SUAC-enriched DBSs to compare and evaluate the performance of these screening tests. Methods: We prepared sets of DBS materials enriched with predetermined SUAC concentrations and distributed samples of these materials, along with a screening practices questionnaire, to laboratories that perform SUAC tests. We compared their reported SUAC concentrations and questionnaire responses to identify screening practices that affect SUAC test outcomes. Results: Data from 2 pilot surveys showed large differences among laboratories in SUAC recoveries, reproducible within-laboratory recoveries, and stable performance of the DBS materials. Results from 257 proficiency test analyses contained a total of 6 false-negative misclassifications. Reported recoveries of added SUAC ranged from 0 to >200%. Low-biased SUAC recoveries were associated with 1 method used by 5 laboratories. All laboratories that reported SUAC recoveries ≥100% used DBS matrix calibrators. Conclusions: The wide ranges of SUAC concentrations reported for pilot and proficiency testing specimens demonstrate a need to harmonize quantitative results among laboratories. Although DBS matrix calibrators are important for optimizing SUAC recoveries, the preparation of these calibrators is not standardized among laboratories. Certified DBS-based SUAC calibrators are needed for accuracy and harmonization.

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Development of a newborn screening tool for mucopolysaccharidosis type I based on bivariate normal limits: Using glycosaminoglycan and alpha‐L‐iduronidase determinations on dried blood spots to predict symptoms

JIMD Reports ◽

10.1002/jmd2.12093 ◽

2020 ◽

Vol 52 (1) ◽

pp. 35-42 ◽

Cited By ~ 3

Author(s):

Thomas J. Langan ◽

Kabir Jalal ◽

Amy L. Barczykowski ◽

Randy L. Carter ◽

Molly Stapleton ◽

...

Keyword(s):

Newborn Screening ◽

Screening Tool ◽

Dried Blood Spots ◽

Type I ◽

Mucopolysaccharidosis Type ◽

Mucopolysaccharidosis Type I ◽

Bivariate Normal ◽

Blood Spots ◽

Normal Limits

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Combined Newborn Screening for Succinylacetone, Amino Acids, and Acylcarnitines in Dried Blood Spots

Clinical Chemistry ◽

10.1373/clinchem.2007.101949 ◽

2008 ◽

Vol 54 (4) ◽

pp. 657-664 ◽

Cited By ~ 102

Author(s):

Coleman Turgeon ◽

Mark J Magera ◽

Pierre Allard ◽

Silvia Tortorelli ◽

Dimitar Gavrilov ◽

...

Keyword(s):

Amino Acids ◽

Newborn Screening ◽

False Negative ◽

Internal Standard ◽

Early Death ◽

Cost Effective ◽

Dried Blood Spots ◽

Type I ◽

Blood Spots ◽

Negative Results

Abstract Background: Tyrosinemia type I (TYR 1) is a disorder causing early death if left untreated. Newborn screening (NBS) for this condition is problematic because determination of the diagnostic marker, succinylacetone (SUAC), requires a separate first-tier or only partially effective second-tier analysis based on tyrosine concentration. To overcome these problems, we developed a new assay that simultaneously determines acylcarnitines (AC), amino acids (AA), and SUAC in dried blood spots (DBS) by flow injection tandem mass spectrometry (MS/MS). Methods: We extracted 3/16-inch DBS punches with 300 μL methanol containing AA and AC stable isotope-labeled internal standards. This extract was derivatized with butanol-HCl. In parallel, we extracted SUAC from the residual filter paper with 100 μL of a 15 mmol/L hydrazine solution containing the internal standard 13C5-SUAC. We combined the derivatized aliquots in acetonitrile for MS/MS analysis of AC and AA with additional SRM experiments for SUAC (m/z 155–137) and 13C5-SUAC (m/z 160–142). Analysis time was 1.2 min. Results: SUAC was increased in retrospectively analyzed NBS samples of 11 TYR 1 patients (length of storage, 52 months to 1 week; SUAC range, 13–81 μmol/L), with Tyr concentrations ranging from 65 to 293 μmol/L in the original NBS analysis. The mean concentration of SUAC in 13 521 control DBS was 1.25 μmol/L. Conclusion: The inclusion of SUAC analysis into routine analysis of AC and AA allows for rapid and cost-effective screening for TYR 1 with no tangible risk of false-negative results.

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Seroepidemiology of HTLV-I in relation to that of HIV-1 in the Gauteng region, South Africa, using dried blood spots on filter papers

Epidemiology and Infection ◽

10.1017/s0950268800001527 ◽

1996 ◽

Vol 117 (2) ◽

pp. 343-348 ◽

Cited By ~ 9

Author(s):

M. B. Taylor ◽

S. P. Parker ◽

H. H. Crewe-Brown ◽

J. McIntyre ◽

W. D. Cubitt

Keyword(s):

South Africa ◽

Virus Type ◽

Dried Blood Spots ◽

Indirect Measurement ◽

Type I ◽

Seroprevalence Rate ◽

T Lymphotropic Virus ◽

Blood Spots ◽

Filter Papers ◽

Hiv 1

SummaryThe seroprevalence of human T-lymphotropic virus type I (HTLV-I), in relation to that of human immunodeficiency virus type 1 (HIV-1), was determined in a comparative unlinked anonymous antenatal and neonatal (for indirect measurement of maternal antibodies) serosurvey in the Gauteng region of South Africa, using dried blood spots (DBS) and modified particle agglutination assays. Samples were confirmed to be antibody positive by western blot. A total of 2582 DBS collected during 1993 and 1994 from subjects of African, European and coloured origin were tested. Ten were confirmed as positive for HTLV-I and 128 for HIV-1. No antibodies to HTLV-I or HIV-l were demonstrated in the 221 women of European and coloured origin who were screened. The HTLV-I seroprevalence rate in subjects of African origin appeared to increase from 0% in 1993 to 0·49% in 1994, while HIV-1 seroprevalence rates of 5·2% and 5·4% were recorded for 1993 and 1994 respectively. No significant differences in HTLV-I and HIV-1 seroprevalence rates were noted for the two areas investigated. These results indicate that HTLV-I should be included in infection control programs, and provide baseline data for monitoring the possible spread of HTLV-I in the heterosexual population in this region.

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Early infant diagnosis of HIV-I infection using dried blood spots among children born to seropositive mothers in Federal Medical Centre (FMC) Lokoja

GSC Advanced Research and Reviews ◽

10.30574/gscarr.2021.8.2.0161 ◽

2021 ◽

Vol 8 (2) ◽

pp. 136-144

Author(s):

Aminat Omope Yusuf ◽

Timothy Olugbenga Ogundeko ◽

MamzhiSeljul Crown Ramyil ◽

Catherine Nadabo ◽

Nkiru Philomena Okoye

Keyword(s):

Transmission Rate ◽

Dried Blood Spots ◽

Antiretroviral Drugs ◽

Medical Centre ◽

High Rate ◽

Type I ◽

Early Infant Diagnosis ◽

Transmission Rates ◽

Blood Spots ◽

Early Infant

Early diagnosis of Human immunodeficiency virus (HIV) in infants provides a critical opportunity to strengthen follow-up of HIV- exposed children using dried blood spots and assure early access to antiretroviral treatment for infected children. This study aimed to determine the prevalence of HVI-1 infection in infants born to HIV-seropositive mothers. Early infant diagnosis of HIV sub-type I was carried out using on dried blood spots of 286 babies born to HIV-I seropositive mothers attending the Federal Medical Centre, Lokoja - Kogi State, Nigeria, between the months of July to December, 2013. Data obtained was analyzed using Gene Amp PCR System 9700. The overall rate of HIV-I vertical transmission from infected mothers to their babies was 14.5%. High transmission rates 63.5%was seen in babies whose mothers could not get any form of interventions with the least transmission rates seen in babies whose mothers either took HAART or were one form of ARV or the other (0 – 1.0%). Babies who took nevirapine as prophylaxis after delivery had lower rate (1%) of transmission. From the 30 women that mix-fed their babies, 6.7% transmission rate was recorded.Lack of antiretroviral drugs by HIV-I positive pregnant women was found to be associated with high rate of HIV-I transmission (p<0.05). Early intervention of mother to child transmission of HIV-1 infection using Highly Active Antiretroviral Therapy, exclusive breastfeeding practice as well as constant visit to Tertiary Hospitals for counseling and management of HIV infection reduced the rate of infection among the infants born to seropositive mothers.

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