A case of vitamin B12 deficiency megaloblastic anemia following total gastrectomy

Vitamin B12 and transcobalamin in bovine milk: Genetic variation and genome-wide association with loci along the genome

In human nutrition, bovine milk is an essential source of bioavailable vitamin B₁₂ and B₁₂-binding proteins, including transcobalamin. In this study, we estimated genetic parameters for milk content of vitamin B₁₂ and transcobalamin using milk samples from 341 and 663 Danish Holstein cows, respectively. Additionally, we conducted whole-genome association analysis to identify SNP and genes associated with vitamin B₁₂ and transcobalamin. Our results indicated moderate to high heritability for vitamin B₁₂ (0.37 ± 0.18) and transcobalamin (0.61 ± 0.13) content in the Danish Holstein. With a significance threshold of -log₁₀ P-value > 5.87, significant associations were detected between SNP in Bos taurus autosome (BTA)17 and the log-transformed transcobalamin content of milk; no significant association was detected for vitamin B₁₂. The significant region in BTA17 was imputed to full sequence for further fine mapping, and the SNP with the most significant associations to transcobalamin were assigned to the transcobalamin 2 (TCN2) gene.

A case of anemia caused by combined vitamin B12 and iron deficiency manifesting as short stature and delayed puberty

Anemia caused by vitamin B12 deficiency resulting from inadequate dietary intake is rare in children in the modern era because of improvements in nutritional status. However, such anemia can be caused by decreased ingestion or impaired absorption and/or utilization of vitamin B12. We report the case of an 18-year-old man with short stature, prepubertal sexual maturation, exertional dyspnea, and severe anemia with a hemoglobin level of 3.3 g/dL. He had a history of small bowel resection from 50 cm below the Treitz ligament to 5 cm above the ileocecal valve necessitated by midgut volvulus in the neonatal period. Laboratory tests showed deficiencies of both vitamin B12 and iron. A bone marrow examination revealed dyserythropoiesis and low levels of hemosiderin particles, and a cytogenetic study disclosed a normal karyotype. After treatment with parenteral vitamin B12 and elemental iron, both anemia and growth showed gradual improvement. This is a rare case that presented with short stature and delayed puberty caused by nutritional deficiency anemia in Korea.