Čes-slov Pediat 2024, 79(3):145-149 | DOI: 10.55095/CSPediatrie2024/024

Vitamin B₁₂ deficiency - another challenge to expand newborn laboratory screening?

Samuel Stanovský¹, Josef Bártl¹, Kristýna Barvíková¹, Petr Chrastina¹, Jakub Krijt¹, Jitka Sokolová¹, Klára Berková², Zbyněk Straňák², Katarína Tichá³, Jan Janota³, Mária Eliášová⁴, Richard Plavka⁴, Jiří Zach⁵, Viktor Kožich¹, Tomáš Honzík¹

¹ Klinika pediatrie a dědičných poruch metabolismu, 1. lékařská fakulta, Univerzita Karlova a Všeobecná fakultní nemocnice, Praha

² Ústav pro péči o matku a dítě, Praha

³ Novorozenecké oddělení, Fakultní nemocnice Motol, Praha

⁴ Klinika gynekologie, porodnictví a neonatologie, 1. lékařská fakulta, Univerzita Karlova a Všeobecná fakultní nemocnice, Praha

⁵ Novorozenecké oddělení, Fakultní Thomayerova nemocnice, Praha

Methods: At least one abnormal primary marker is required for suspected B₁₂ deficiency: propionylcarnitine > 3.8 μmol/l, propionylcarnitine/acetylcarnitine ratio > 0.3, methionine < 7 μmol/l,

propionylcarnitine/methionine ratio > 0.5 (determined by tandem mass spectrometry). Secondary markers include methylmalonic acid (MMA) > 2.5 μmol/l and total homocysteine (tHcy) > 12 μmol/l. In the case of NLS positivity, both the newborn and the mother undergo a Cbl absorption test. We determine total B₁₂ (measured by electrochemiluminescence immunoassay), holoTC (measured by chemiluminescence

immunoassay), folates (measured by electrochemiluminescence immunoassay), serum MMA



(measured by liquid chromatography-tandem mass spectrometry), tHcy (measured by high-performance liquid chromatography), and selected sulfur metabolites in both newborn and mother. We assess maternal markers of chronic gastritis.

Results: As of 21 February 2024, we evaluated B₁₂ deficiency in 20,419 dry blood

spots (86.1% of the samples collected). We identified 863 newborns with positive findings for at least one of the primary markers (2nd tier 4.2%). Overall, 6 newborns had elevated MMA levels, with 4 cases classified as true positivity, 1 false positivity, and 1 case indicating combined malonic/methylmalonic aciduria. In our preliminary results, the incidence of neonatal B₁₂ deficiency reached

1 : 5,105 (95% CI 1:1,994-1:8,735).

Conclusion: Preliminary data from our study demonstrate the high incidence of neonatal B₁₂ deficiency in cooperating Prague maternity units. The results may serve as a scientific basis for NLS expansion in the Czech Republic.

Keywords: novorozenecký screening, kobalamin, vitamin B₁₂, deficit B₁₂

Accepted: April 3, 2024; Published: May 1, 2024  Show citation