Addition of galactose‐1‐phosphate measurement enhances newborn screening for classical galactosemia

Abstract

Galactosemia is an inborn disorder of carbohydrate metabolism of which early detection can prevent severe illness. Although the assay for galactose‐1‐phosphate uridyltransferase (GALT) enzyme activity has been available since the 1960s, many issues prevented it from becoming universal. In order to develop the Israeli newborn screening pilot algorithm for galactosemia, flow injection analysis tandem mass spectrometry measurement of galactose‐1‐phosphate in archived dried blood spots from newborns with classical galactosemia, galactosemia variants, epimerase deficiency, and normal controls, was conducted. Out of 431 330 newborns screened during the pilot study (30 months), two with classical galactosemia and four with epimerase deficiency were identified and confirmed. Five false positives and no false negatives were recorded. Following this pilot study, the Israeli final and routine newborn screening algorithm, as recommended by the Advisory Committee to the National Newborn Screening Program, now consists of galactose‐1‐phosphate measurement integrated into the routine tandem mass spectrometry panel as the first‐tier screening test, and GALT enzyme activity as the second‐tier performed to identify only newborns suspected to be at risk for classical galactosemia. The GALT enzyme activity cut‐off used in the final algorithm was lowered in order to avoid false positives.

Current Status of Newborn Bloodspot Screening Worldwide 2024: A Comprehensive Review of Recent Activities (2020–2023)

“…To develop a NBS pilot algorithm for galactosemia, archived dried bloodspots from newborns with GALT, galactosemia variants, and normal controls were analyzed by MS/MS for galactose-1-phosphate (Gal-1-P) by FIA MS/MS. Based on a successful pilot, a screening algorithm with Gal-1-P as the first-tier screening test, and GALT enzyme activity as the second-tier to identify newborns suspected to be at risk for classical galactosemia has been implemented [ 1349 ]. Another FIA MS/MS study demonstrated the feasibility of screening newborns for CTX, a progressive metabolic leukodystrophy, using two-tier screening with FIA MS/MS and LC MS/MS [ 1350 ].…”

Twelve-year review of galactosemia newborn screening in Taiwan: Evolving methods and insights

“…Therefore, we routinely re-screen cases after fully oral feeding to decrease the possibility of false negative. Alternatively, assessing markers such as Gal-1-P [ 40 , 41 ] instead of TGal could be advantageous in accurately detecting elevated Gal-1-P levels in newborns. However, a caveat exists: patients with GALK deficiency may present with normal Gal-1-P levels or TGal and might be overlooked in such screenings.…”