Study Quantifies Benefit of Newborn Screening for Vitamin B12 Deficiency

Newborn screening for neonatal vitamin B12 deficiency may lead to a fourfold reduction in chances of developing symptomatic vitamin B12 in the first year of life compared with infants without newborn screening, a hospital-based surveillance study in Germany indicates.

Vitamin B12 deficiency can impede development in infants, but the true impact of newborn screening versus no screening had not been known in Germany. Early treatment had been shown to be linked with normal development in infants who got newborn screening, but left unclear was how many who had newborn screening would have progressed to symptomatic vitamin B12 deficiency without treatment. Thus formal evidence for the benefit of the screening was lacking.

The nationwide surveillance study, led by Ulrike Mütze, MD, with the Heidelberg University Center for Child and Adolescent Medicine, was published online in Pediatrics. It used prospectively collected data from incident cases of infants under 12 months of age with vitamin B12 deficiency from 2021 to 2022.

The researchers analyzed 61 cases of vitamin B12 deficiency reported to the German Pediatric Surveillance Unit. They were either identified by newborn screening (n = 31) or diagnosed after the onset of suggestive symptoms (non-newborn screening; n = 30).

At a median 4 months of age, the great majority (90%) of the infants identified by newborn screening were still asymptomatic, while the non-newborn screening cohort presented with muscular hypotonia (68%), anemia (58%), developmental delay (44%), microcephalia (30%), and seizures (12%).

Symptomatically diagnosed vitamin B12 deficiency in the baby’s first year was reported four times more frequently in infants who did not receive newborn screening for neonatal vitamin B12 deficiency compared with those screened for vitamin B12 as newborns (Fisher’s Exact Test; odds ratio, 4.12 [95% confidence interval, 1.29-17.18], P = .008).

Clinical presentation of vitamin B12 deficiency in infants usually starts in the first months and reportedly includes, in addition to developmental delay, feeding difficulties, muscular hypotonia and weakness, severe failure to thrive, irritability, lethargy, and (as late symptoms) megaloblastic anemia and brain atrophy.

The current study confirmed these reports and highlighted that the most common presentations in symptomatic infantile vitamin B12 deficiency were muscular hypotonia, anemia, developmental delay, malnutrition or failure to thrive, and microcephalia, brain atrophy, or delayed myelination.

Stephen Walker, MD, a pediatric neurologist at University of Alabama, Birmingham, who was not involved with the study, said newborn screening for vitamin B12 deficiency is routine in the United States.

“In Alabama, we’re generally the last to adopt any of these newborn screenings ... and we’ve been doing it for several years,” he said. Vitamin B12 deficiency is one of 59 conditions included in the state’s newborn blood spot screening. In the United States, he added, when deficiencies are identified, cases are quickly referred to genetic or nutritional specialists.

In the Mütze et al. study, the authors conclude, “The incidence of symptomatic vitamin B12 deficiency accounts for about half of the estimated incidence of the vitamin B12 deficiency identified by newborn screening [NBS]. This supports the notion that not all newborns identified will develop a symptomatic infantile vitamin B12 deficiency but at the same time [this study demonstrates] the high beneficial potential of NBS for vitamin B12 deficiency.”

Dr. Mütze received a research grant from the Medical Faculty of Heidelberg University, Germany. Dr. Kölker, Dr. Hoffmann, and Dr. Mütze received research grants for their work on newborn screening from the Dietmar Hopp Foundation, St. Leon-Rot, Germany. Dr. Hoffmann, Dr. Janzen, and Dr. Röschinger are principal investigators for newborn screening pilot studies including neonatal vitamin B12 deficiency. The other authors have no relevant disclosures. Dr. Walker reports no relevant financial relationships.

Newborn screening for neonatal vitamin B12 deficiency may lead to a fourfold reduction in chances of developing symptomatic vitamin B12 in the first year of life compared with infants without newborn screening, a hospital-based surveillance study in Germany indicates.

Vitamin B12 deficiency can impede development in infants, but the true impact of newborn screening versus no screening had not been known in Germany. Early treatment had been shown to be linked with normal development in infants who got newborn screening, but left unclear was how many who had newborn screening would have progressed to symptomatic vitamin B12 deficiency without treatment. Thus formal evidence for the benefit of the screening was lacking.

The nationwide surveillance study, led by Ulrike Mütze, MD, with the Heidelberg University Center for Child and Adolescent Medicine, was published online in Pediatrics. It used prospectively collected data from incident cases of infants under 12 months of age with vitamin B12 deficiency from 2021 to 2022.

The researchers analyzed 61 cases of vitamin B12 deficiency reported to the German Pediatric Surveillance Unit. They were either identified by newborn screening (n = 31) or diagnosed after the onset of suggestive symptoms (non-newborn screening; n = 30).

At a median 4 months of age, the great majority (90%) of the infants identified by newborn screening were still asymptomatic, while the non-newborn screening cohort presented with muscular hypotonia (68%), anemia (58%), developmental delay (44%), microcephalia (30%), and seizures (12%).

Symptomatically diagnosed vitamin B12 deficiency in the baby’s first year was reported four times more frequently in infants who did not receive newborn screening for neonatal vitamin B12 deficiency compared with those screened for vitamin B12 as newborns (Fisher’s Exact Test; odds ratio, 4.12 [95% confidence interval, 1.29-17.18], P = .008).

Clinical presentation of vitamin B12 deficiency in infants usually starts in the first months and reportedly includes, in addition to developmental delay, feeding difficulties, muscular hypotonia and weakness, severe failure to thrive, irritability, lethargy, and (as late symptoms) megaloblastic anemia and brain atrophy.

The current study confirmed these reports and highlighted that the most common presentations in symptomatic infantile vitamin B12 deficiency were muscular hypotonia, anemia, developmental delay, malnutrition or failure to thrive, and microcephalia, brain atrophy, or delayed myelination.

Stephen Walker, MD, a pediatric neurologist at University of Alabama, Birmingham, who was not involved with the study, said newborn screening for vitamin B12 deficiency is routine in the United States.

“In Alabama, we’re generally the last to adopt any of these newborn screenings ... and we’ve been doing it for several years,” he said. Vitamin B12 deficiency is one of 59 conditions included in the state’s newborn blood spot screening. In the United States, he added, when deficiencies are identified, cases are quickly referred to genetic or nutritional specialists.

In the Mütze et al. study, the authors conclude, “The incidence of symptomatic vitamin B12 deficiency accounts for about half of the estimated incidence of the vitamin B12 deficiency identified by newborn screening [NBS]. This supports the notion that not all newborns identified will develop a symptomatic infantile vitamin B12 deficiency but at the same time [this study demonstrates] the high beneficial potential of NBS for vitamin B12 deficiency.”

Dr. Mütze received a research grant from the Medical Faculty of Heidelberg University, Germany. Dr. Kölker, Dr. Hoffmann, and Dr. Mütze received research grants for their work on newborn screening from the Dietmar Hopp Foundation, St. Leon-Rot, Germany. Dr. Hoffmann, Dr. Janzen, and Dr. Röschinger are principal investigators for newborn screening pilot studies including neonatal vitamin B12 deficiency. The other authors have no relevant disclosures. Dr. Walker reports no relevant financial relationships.

Newborn screening for neonatal vitamin B12 deficiency may lead to a fourfold reduction in chances of developing symptomatic vitamin B12 in the first year of life compared with infants without newborn screening, a hospital-based surveillance study in Germany indicates.

Vitamin B12 deficiency can impede development in infants, but the true impact of newborn screening versus no screening had not been known in Germany. Early treatment had been shown to be linked with normal development in infants who got newborn screening, but left unclear was how many who had newborn screening would have progressed to symptomatic vitamin B12 deficiency without treatment. Thus formal evidence for the benefit of the screening was lacking.

The nationwide surveillance study, led by Ulrike Mütze, MD, with the Heidelberg University Center for Child and Adolescent Medicine, was published online in Pediatrics. It used prospectively collected data from incident cases of infants under 12 months of age with vitamin B12 deficiency from 2021 to 2022.

The researchers analyzed 61 cases of vitamin B12 deficiency reported to the German Pediatric Surveillance Unit. They were either identified by newborn screening (n = 31) or diagnosed after the onset of suggestive symptoms (non-newborn screening; n = 30).

At a median 4 months of age, the great majority (90%) of the infants identified by newborn screening were still asymptomatic, while the non-newborn screening cohort presented with muscular hypotonia (68%), anemia (58%), developmental delay (44%), microcephalia (30%), and seizures (12%).

Symptomatically diagnosed vitamin B12 deficiency in the baby’s first year was reported four times more frequently in infants who did not receive newborn screening for neonatal vitamin B12 deficiency compared with those screened for vitamin B12 as newborns (Fisher’s Exact Test; odds ratio, 4.12 [95% confidence interval, 1.29-17.18], P = .008).

Clinical presentation of vitamin B12 deficiency in infants usually starts in the first months and reportedly includes, in addition to developmental delay, feeding difficulties, muscular hypotonia and weakness, severe failure to thrive, irritability, lethargy, and (as late symptoms) megaloblastic anemia and brain atrophy.

The current study confirmed these reports and highlighted that the most common presentations in symptomatic infantile vitamin B12 deficiency were muscular hypotonia, anemia, developmental delay, malnutrition or failure to thrive, and microcephalia, brain atrophy, or delayed myelination.

Stephen Walker, MD, a pediatric neurologist at University of Alabama, Birmingham, who was not involved with the study, said newborn screening for vitamin B12 deficiency is routine in the United States.

“In Alabama, we’re generally the last to adopt any of these newborn screenings ... and we’ve been doing it for several years,” he said. Vitamin B12 deficiency is one of 59 conditions included in the state’s newborn blood spot screening. In the United States, he added, when deficiencies are identified, cases are quickly referred to genetic or nutritional specialists.

In the Mütze et al. study, the authors conclude, “The incidence of symptomatic vitamin B12 deficiency accounts for about half of the estimated incidence of the vitamin B12 deficiency identified by newborn screening [NBS]. This supports the notion that not all newborns identified will develop a symptomatic infantile vitamin B12 deficiency but at the same time [this study demonstrates] the high beneficial potential of NBS for vitamin B12 deficiency.”

Dr. Mütze received a research grant from the Medical Faculty of Heidelberg University, Germany. Dr. Kölker, Dr. Hoffmann, and Dr. Mütze received research grants for their work on newborn screening from the Dietmar Hopp Foundation, St. Leon-Rot, Germany. Dr. Hoffmann, Dr. Janzen, and Dr. Röschinger are principal investigators for newborn screening pilot studies including neonatal vitamin B12 deficiency. The other authors have no relevant disclosures. Dr. Walker reports no relevant financial relationships.