Publications by authors named "Denise Salazar"

8 Publications

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Arginine to ornithine ratio as a diagnostic marker in patients with positive newborn screening for hyperargininemia.

Mol Genet Metab Rep 2021 Jun 3;27:100735. Epub 2021 Mar 3.

Biochemical Genetics, Advanced Diagnostics-Genetics, Genomics and R&D, Quest Diagnostics Nichols Institute, San Juan Capistrano, CA 92675, United States of America.

Arginase deficiency is a rare inborn error of metabolism that interrupts the final step of the urea cycle. Untreated individuals often present with episodic hyperammonemia, developmental delay, cognitive impairment, and spasticity in early childhood. The newborn screening (NBS) algorithms for arginase deficiency vary between individual states in the US but often include hyperargininemia and elevated arginine to ornithine (Arg/Orn) ratio. Here, we report 14 arginase deficiency cases, including two patients with positive NBS for hyperargininemia in whom the diagnosis of arginase deficiency was delayed owing to normal or near normal plasma arginine levels on follow-up testing. To improve the detection capability for arginase deficiency, we evaluated plasma Arg/Orn ratio as a secondary diagnostic marker in positive NBS cases for hyperargininemia. We found that plasma Arg/Orn ratio combined with plasma arginine was a better marker than plasma arginine alone to differentiate patients with arginase deficiency from unaffected newborns. In fact, elevated plasma arginine in combination with an Arg/Orn ratio of ≥1.4 identified all 14 arginase deficiency cases. In addition, we examined the impact of age on plasma arginine and ornithine levels. Plasma arginine increased 0.94 μmol/L/day while ornithine was essentially unchanged in the first 31 days of life, which resulted in a similar increasing trend for the Arg/Orn ratio (0.01/day). This study demonstrated that plasma Arg/Orn ratio as a secondary diagnostic marker improved the detection capability for arginase deficiency in newborns with hyperargininemia, which will allow timely detection of arginase deficiency and hence initiation of treatment before developing symptoms.
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http://dx.doi.org/10.1016/j.ymgmr.2021.100735DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7937551PMC
June 2021

Inborn Errors of Metabolism and the Gastrointestinal Tract.

Gastroenterol Clin North Am 2019 06 1;48(2):183-198. Epub 2019 Apr 1.

Quest Diagnostics, 33608 Ortega Highway, San Juan Capistrano, CA 92690, USA.

Inborn errors of metabolism (IEMs) are usually recognized by characteristic neurologic and metabolic manifestations and sometimes by dysmorphism. However, IEMs can present with a wide variety of gastrointestinal manifestations, whether as the primary or a minor clinical symptom. Regardless, gastrointestinal and hepatic manifestations of IEMs are important clinical features that can help identify an underlying defect; these disorders should be taken into consideration as part of a patient's clinical assessment. It is prudent to include metabolic disorders in the differential diagnosis because in some cases, gastrointestinal symptoms may be the only presenting feature in a patient with an underlying IEM.
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http://dx.doi.org/10.1016/j.gtc.2019.02.001DOI Listing
June 2019

Laboratory diagnostic approaches in metabolic disorders.

Ann Transl Med 2018 Dec;6(24):470

Quest Diagnostics, Inc., Denise Salazar and Pranoot Tanpaiboon, San Juan Capistrano, CA, USA.

The diagnosis of inborn errors of metabolism (IEM) takes many forms. Due to the implementation and advances in newborn screening (NBS), the diagnosis of many IEM has become relatively easy utilizing laboratory biomarkers. For the majority of IEM, early diagnosis prevents the onset of severe clinical symptoms, thus reducing morbidity and mortality. However, due to molecular, biochemical, and clinical variability of IEM, not all disorders included in NBS programs will be detected and diagnosed by screening alone. This article provides a general overview and simplified guidelines for the diagnosis of IEM in patients with and without an acute metabolic decompensation, with early or late onset of clinical symptoms. The proper use of routine laboratory results in the initial patient assessment is also discussed, which can help guide efficient ordering of specialized laboratory tests to confirm a potential diagnosis and initiate treatment as soon as possible.
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http://dx.doi.org/10.21037/atm.2018.11.05DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6331366PMC
December 2018

Outcome of infants diagnosed with 3-methyl-crotonyl-CoA-carboxylase deficiency by newborn screening.

Mol Genet Metab 2012 Aug 20;106(4):439-41. Epub 2012 Apr 20.

Department of Pediatrics, University of Pittsburgh Medical Center, Pittsburgh, PA, USA.

Introduction: 3-Methyl CoA carboxylase (3-MCC) deficiency is an inborn error of metabolism in the catabolism of the amino acid leucine. Original reports suggested this disorder was associated with significant neurological and biochemical effects. However newborn screening has identified a higher than expected incidence of this disorder with apparent normal outcome in most cases.

Method: A retrospective analysis of thirty-five cases of 3-MCC deficiency identified by newborn screening and diagnosed by enzyme or molecular analysis.

Results: There was a strong inverse correlation between initial C5OH level and residual enzyme activity. A few reports of hypoglycemia, ketosis, poor feeding/failure to thrive or fasting intolerance were reported, but there was no clear relationship between symptoms and residual enzyme activity. Developmental outcome included several children with mental retardation (including one with Down syndrome and one with schizencephaly) and two with Autism Spectrum disorders but there was no apparent relationship to residual enzyme activity. Free carnitine deficiency was relatively common.

Discussion: Although residual enzyme activity was clearly related to metabolite elevation, there was no apparent relationship with other measures of outcome. The number of reports of neurologic abnormalities or metabolic symptoms (poor feeding, hypoglycemia, fasting intolerance, etc.) is concerning, but the significance is unclear in this retrospective sample.
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http://dx.doi.org/10.1016/j.ymgme.2012.04.006DOI Listing
August 2012

The sensitivity and specificity of hyperglycosylated hCG (hhCG) levels to reliably diagnose clinical IVF pregnancies at 6 days following embryo transfer.

J Assist Reprod Genet 2012 Jul 24;29(7):609-14. Epub 2012 Apr 24.

Quest Diagnostics Nichols Institute, San Juan Capistrano, CA 92675-2042, USA.

Objective: To determine the sensitivity and specificity of hyperglycosylated hCG (hhCG) measurements for the diagnosis of clinical pregnancies in the IVF setting and how soon post embryo transfer (ET) a pregnancy can be detected using an ultrasensitive (hhCG) assay. To determine if a single, early hhCG measurement can discriminate between biochemical and clinical pregnancies.

Design: A 4 center prospective blinded clinical trial was performed with patients undergoing IVF-ET. Patients had blood drawn and submitted for hhCG analysis on the day of ET and at days 4, 6, 8, and 12 thereafter. First morning urines were collected and submitted for hhCG analysis on days 0, 4, 6, 8, 10 and 12.

Setting: Fertility Centers

Outcome Measures: Clinical pregnancies were defined as an ultrasound study demonstrating a gestational sac and/or heart beat at appropriate gestational ages.

Results: Fifty-six of 58 enrolled patients completed the study. There were 25 clinical and 6 biochemical pregnancies. For blastocyst transfers, a single serum or urine hhCG measurement identified pregnancies (both biochemical and clinical) at 6 days post ET with 100% sensitivity and specificity. There were 6 biochemical pregnancies, all following blastocyst transfers. All of these pregnancies were identified by lower values.
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http://dx.doi.org/10.1007/s10815-012-9774-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3401259PMC
July 2012

Asymptomatic maternal combined homocystinuria and methylmalonic aciduria (cblC) detected through low carnitine levels on newborn screening.

J Pediatr 2009 Dec;155(6):924-7

Division of Medical Genetics, Harbor-UCLA Medical Center, Torrance, CA 90502, USA.

A symptom-free woman gave birth to a girl with a low carnitine level on newborn screening. The baby was unaffected, but the mother had biochemical abnormalities and mutations characteristic of the cblC defect of vitamin B(12) metabolism (late-onset form). This patient with cblC was detected through her infant's newborn screening.
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http://dx.doi.org/10.1016/j.jpeds.2009.06.046DOI Listing
December 2009

Improving accuracy of Tay Sachs carrier screening of the non-Jewish population: analysis of 34 carriers and six late-onset patients with HEXA enzyme and DNA sequence analysis.

Pediatr Res 2010 Feb;67(2):217-20

Molecular Genetics Department, Quest Diagnostics Nichols Institute, San Juan Capistrano, California 92690, USA.

The purpose of this study was to determine whether combining different testing modalities namely beta-hexosaminidase A (HEXA) enzyme analysis, HEXA DNA common mutation assay, and HEXA gene sequencing could improve the sensitivity for carrier detection in non-Ashkenazi (AJ) individuals. We performed a HEXA gene sequencing assay, a HEXA DNA common mutation assay, and a HEXA enzyme assay on 34 self-reported Tay-Sachs disease (TSD) carriers, six late-onset patients with TSD, and one pseudodeficiency allele carrier. Sensitivity of TSD carrier detection was 91% for gene sequencing compared with 91% for the enzyme assay and 52% for the DNA mutation assay. Gene sequencing combined with enzyme testing had the highest sensitivity (100%) for carrier detection. Gene sequencing detected four novel mutations, three of which are predicted to be disease causing [118.delT, 965A-->T (D322V), and 775A-->G (T259A)]. Gene sequencing is useful in identifying rare mutations in patients with TSD and their families, in evaluating spouses of known carriers for TSD who have indeterminate enzyme analysis and negative for common mutation analysis, and in resolving ambiguous enzyme testing results.
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http://dx.doi.org/10.1203/PDR.0b013e3181c6e318DOI Listing
February 2010

Maternal glutaric acidemia, type I identified by newborn screening.

Mol Genet Metab 2008 May 4;94(1):132-4. Epub 2008 Mar 4.

Department of Pediatrics, University of California, Los Angeles, CA 90095-1752, USA.

We report two women with glutaric acidemia type I in whom the diagnosis was unsuspected until a low carnitine level was found in their newborn children. Both mothers had low carnitine in plasma. In the first, organic acid analysis was only done after fibroblast studies revealed normal carnitine uptake. Having learned from the first family, organic acid analysis was done immediately in the mother of family 2. In both, the plasma acylcarnitine profile was normal but both excreted the metabolites typical of their disorder. One of the women was a compound heterozygote for distinct mutations in the glutaric acid dehydrogenase gene, whereas the second was either homozygous or hemizygous for a mutation in Exon 6 of the gene.
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http://dx.doi.org/10.1016/j.ymgme.2008.01.005DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2474772PMC
May 2008