Breastfed Infants With Spells, Tremor, or Irritability: Rule Out Vitamin B12 Deficiency

Biochemical, Nutritional, and Clinical Parameters of Vitamin B12 Deficiency in Infants: A Systematic Review and Analysis of 292 Cases Published between 1962 and 2022

Pooled data from published reports on infants with clinically diagnosed vitamin B12 (B12) deficiency were analyzed with the purpose of describing the presentation, diagnostic approaches, and risk factors for the condition to inform prevention strategies. An electronic (PubMed database) and manual literature search following the PRISMA approach was conducted (preregistration with the Open Science Framework, accessed on 15 February 2023). Data were described and analyzed using correlation analyses, Chi-square tests, ANOVAs, and regression analyses, and 102 publications (292 cases) were analyzed. The mean age at first symptoms (anemia, various neurological symptoms) was four months; the mean time to diagnosis was 2.6 months. Maternal B12 at diagnosis, exclusive breastfeeding, and a maternal diet low in B12 predicted infant B12, methylmalonic acid, and total homocysteine. Infant B12 deficiency is still not easily diagnosed. Methylmalonic acid and total homocysteine are useful diagnostic parameters in addition to B12 levels. Since maternal B12 status predicts infant B12 status, it would probably be advantageous to target women in early pregnancy or even preconceptionally to prevent infant B12 deficiency, rather than to rely on newborn screening that often does not reliably identify high-risk children.

[Evaluation and optimization of newborn screening by structured long-term follow-up-using the example of inherited metabolic diseases]

Newborn screening (NBS) is a highly successful secondary prevention program with the goal of preventing severe sequelae of congenital, mostly genetic, diseases by identifying them as early as possible, ideally in the pre-symptomatic period. Studies to date have shown the important achievements of NBS programs but also reveal a number of relevant weaknesses. These include the often incompletely understood natural history and phenotypic diversity of rare diseases as well as the inadequate ability to accurately predict individual disease severity at an early stage and thus the uncertainties in case definition, risk stratification, and treatment indication.In light of the rapid developments in high-throughput genetic technologies and the associated opportunities for substantial future expansion of NBS programs, it seems overdue to make structured long-term follow-up and the subsequent evaluation of the long-term health benefits mandatory for individuals with rare diseases identified through NBS. This article explains the importance of long-term follow-up for the evaluation and continuous optimization of the screening. Long-term clinical outcomes of people with inherited metabolic diseases identified by NBS are presented as examples.

Parental perspectives of episodic irritability in an ultra-rare genetic disorder associated with NACC1

BACKGROUND

A recurrent de novo variant (c.892C>T) in NACC1 causes a neurodevelopmental disorder with epilepsy, cataracts, feeding difficulties, and delayed brain myelination (NECFM). An unusual and consistently reported feature is episodic extreme irritability and inconsolability. We now characterize these episodes, their impact on the family, and ascertain treatments that may be effective. Parents of 14 affected individuals provided narratives describing the irritability episodes, including triggers, behavioral and physiological changes, and treatments. Simultaneously, parents of 15 children completed the Non-communicating Children's Pain Checklist-Revised (NCCPC-R), a measure to assess pain in non-verbal children.

RESULTS

The episodes of extreme irritability include a prodromal, peak, and resolving phase, with normal periods in between. The children were rated to have extreme pain-related behaviors on the NCCPC-R scale, although it is unknown whether the physiologic changes described by parents are caused by pain. Attempted treatments included various classes of medications, with psychotropic and sedative medications being most effective (7/15). Nearly all families (13/14) describe how the episodes have a profound impact on their lives.

CONCLUSIONS

NECFM caused by the recurrent variant c.892C>T is associated with a universal feature of incapacitating episodic irritability of unclear etiology. Further understanding of the pathophysiology can lead to more effective therapeutic strategies.

Vitamin B12 Deficiency (Un-)Detected Using Newborn Screening in Norway

Untreated vitamin B12 (B12) deficiency may cause delayed development in infants. Several newborn screening (NBS) programs have reported an increased detection rate of B12 deficiency when second-tier dried blood spot (DBS) analyses of total homocysteine (tHcy) and methylmalonic acid (MMA) are included. This is a retrospective study of newborns reported from NBS during 2012−2021 with confirmed B12 deficiency. DBSs were retrieved from the NBS biobank for second-tier MMA and tHcy analysis. Thirty-one newborns were diagnosed with B12 deficiency out of 552970 screened. Twenty-five were ascertained from sixty-one false positive (FP) cases of methylmalonic acidemia and propionic acidemia (PA), and six infants screened positive for other NBS metabolic diseases with propionylcarnitine (C3) in the normal range. In the original DBS, 7/23 (30%) and 12/23 (52%) of B12-deficient newborns with FP methylmalonic acidemia/PA had MMA and tHcy > 99th percentile. B12 deficiency was a common differential diagnosis of screening positive for methylmalonic and PA. C3 failed to identify a subset of newborns with B12 deficiency. Second-tier MMA and tHcy analyses in the DBS showed suboptimal sensitivity for identifying infants with B12 deficiency. The shortcomings of NBS should be acknowledged when considering B12 deficiency as a primary target of NBS panels.

A Retrospective Evaluation of the Predictive Value of Newborn Screening for Vitamin B12 Deficiency in Symptomatic Infants Below 1 Year of Age

BACKGROUND

The sensitivity of newborn screening (NBS) in detecting infants that later develop symptomatic vitamin B12 deficiency is unknown. We evaluated the predictive value using NBS algorithms in detecting infants that later were clinically diagnosed with symptomatic B12 deficiency. Furthermore, we investigated whether being born in a hospital using nitrous oxide (N₂O) as pain relief in labor may have had an impact on total homocysteine at NBS.

METHODS

We retrospectively retrieved NBS data and analyzed total homocysteine, methylmalonic acid and methyl citrate on stored NBS dried blood spots (DBS) of 70 infants diagnosed with symptomatic B12 deficiency and compared them to 646 matched and 434 unmatched DBS controls to evaluate the Austrian and Heidelberg B12 NBS algorithms.

RESULTS

The sensitivity of NBS in detecting infants later diagnosed with symptomatic B12 deficiency at median age 10.9 weeks was ≤10%. Total homocysteine was higher in DBS for the unmatched controls who were born in hospitals providing N₂O compared to in hospitals not providing N₂O, with median total homocysteine 4.0 µmol/L compared to 3.5 µmol/L (n = 434, 95% CI 0.04-0.87, p = 0.03).

CONCLUSION

NBS algorithms were unable to identify most infants diagnosed with symptomatic B12 deficiency after the neonatal period. Being born in hospitals providing N₂O may impact total homocysteine at NBS.

Nitrous oxide in labour predicted newborn screening total homocysteine and is a potential risk factor for infant vitamin B12 deficiency

AIM

Risk factors for vitamin B12 deficiency in infants are not fully understood. The aim of the study was to assess predictors of total homocysteine and methylmalonic acid analysed in newborn screening dried blood spots.

METHODS

In a Norwegian case control study, we analysed total homocysteine and methylmalonic acid in newborn screening dried blood spots of 86 infants clinically diagnosed with vitamin B12 deficiency during 2012-2018. Results were compared to 252 healthy infants and 400 dried blood spot controls. Medical records were reviewed, and mothers completed questionnaires.

RESULTS

Both total homocysteine and methylmalonic acid were significantly higher on newborn screening dried blood spots in infants later clinically diagnosed with vitamin B12 deficiency than controls. Multiple regression analysis showed that the dose of nitrous oxide during labour was the strongest predictor for total homocysteine level in newborn screening dried blood spots for all infants, with larger effect in infants later clinically diagnosed with vitamin B12 deficiency than controls.

CONCLUSION

Nitrous oxide dose during labour was a predictor for total homocysteine and may impact the interpretation of total homocysteine analysis in newborn screening. Nitrous oxide is suggested as a contributing risk factor for infants prone to develop vitamin B12 deficiency.

Lower iron stores were associated with supoptimal gross motor scores in infants at 3-7 months

Aim

To investigate associations between iron status and gross motor scores in infants aged 3–7 months.

Methods

In a prospective study, 252 infants aged 3–7 months were examined using the age‐standardised Alberta Infant Motor Scale (AIMS) prior to analysing iron status in 250 infants. Combined AIMS and ferritin results were assessed in 226 infants, whereas AIMS and reticulocyte haemoglobin (ret‐Hb) results were obtained for 61 infants. We used logistic regressions and receiver operator characteristics to analyse our data.

Results

With AIMS z‐score <10th percentile as outcome measure, optimal cut‐off value for ferritin was 51 μg/L (sensitivity 86%, specificity 81%) and 28 pg for ret‐Hb (sensitivity 86%, specificity 85%). The area under the curve for ferritin and ret‐Hb was 0.886 and 0.896, respectively (n = 61). Ferritin <51 μg/L predicted an AIMS z‐score <10th percentile in a logistic regression (OR 3.3, 95% CI 1.4–7.5, p = 0.006, n = 226). Six of 14 (43%) infants with ret‐Hb <28 pg scored <10th percentile on AIMS compared to 1/47 (2.1%) infants with ret‐Hb ≥28 μg/L (Exact, p < 0.001).

Conclusion

Reticulocyte haemoglobin of <28 pg and ferritin <51 μg/L were associated with suboptimal gross motor scores in infants 3–7 months.