oa Role of Homocysteine Measurement for Early Diagnosis of Vitamin B12 Deficiency in the First Days of Life

Background: Vitamin B12 (vit B12) deficiency is one of the major causes of megaloblastic anaemia and should be avoided as early as possible since a supplementation of mother and child can prevent neurological symptoms of the baby. Furthermore, the neurological symptoms of affected children are (partially) reversible. Elevated methylmalonic acid in urine and homocysteine (Hcy) in plasma are sensitive indicators. In the State of Qatar, extended newborn screening of classical homocystinuria was realized for all 73,994 neonates in last 4.5 years. Newborns with slightly elevated Hcy levels in dried blood spots (DBS) were followed up with regard to possible vit B12 deficiency. In addition, the propionylcarnitine (C3) levels were analysed.

Methods: Determination of Hcy in DBS was performed using liquid chromatography electrospray tandem mass spectrometry. C3 levels were obtained from general newborn screening. The vit B12 levels in plasma were analysed spectrophotometrically.

Results: In all, 117 cases with mildly elevated Hcy levels were found. 65 were diagnosed with vit B12 deficiency. Only 9 of these 65 newborns had abnormal C3 levels. No correlation was found in this group between Hcy and C3 levels.

Conclusion: Extended neonatal screening of Hcy is a useful tool for early diagnosis and treatment of vit B12 deficiency.