Chapter title |
False-Positive Newborn Screen Using the Beutler Spot Assay for Galactosemia in Glucose-6-Phosphate Dehydrogenase Deficiency
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Chapter number | 34 |
Book title |
JIMD Reports, Volume 36
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Published in |
JIMD Reports, January 2017
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DOI | 10.1007/8904_2016_34 |
Pubmed ID | |
Book ISBNs |
978-3-66-256137-9, 978-3-66-256138-6
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Authors |
Grace Stuhrman, Stefanie J. Perez Juanazo, Kea Crivelly, Jennifer Smith, Hans Andersson, Eva Morava, Stuhrman, Grace, Perez Juanazo, Stefanie J., Crivelly, Kea, Smith, Jennifer, Andersson, Hans, Morava, Eva |
Abstract |
Classical galactosemia is detected through newborn screening by measuring galactose-1-phosphate uridylyltransferase (GALT) in the USA primarily via the Beutler spot assay. We report on an 18-month-old patient with glucose-6-phosphate dehydrogenase (G6PD) deficiency that was originally diagnosed with classical galactosemia. The patient presented with elevated liver function enzymes and bilirubinemia and was immediately treated with soy-based formula. Confirmatory tests revealed deficiency of the GALT enzyme, however, full-sequencing of GALT was normal, suggestive of a different ideology. The Beutler spot assay uses three other enzymatic steps in addition to GALT. A deficiency in either of these enzymes can result in suspected decreased GALT activity when using the Beutler assay. Congenital Disorders of Glycosylation screening for phosphoglucomutase-1 deficiency was negative. Quantitative analysis of G6PD enzyme in red blood cells showed a severe deficiency and a deletion in G6PD. Soy-formula, the standard treatment for galactosemia, has been reported to trigger hemolysis in G6PD deficient patients. G6PD and phosphoglucomutase-1 deficiencies should be considered when confirmatory tests are negative for pathogenic variants in GALT and galactose-1-phosphate level is normal. |
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