Cobalamin deficiency presenting with cutaneous hyperpigmentation: a report of two siblings

Photodegradation of cobalamins in aqueous solutions and in human blood

Vitamin B12 (cobalamin) is required for proper red blood cell formation, neurologic function, and DNA synthesis. Cobalamins in solutions are light sensitive, but no comprehensive study has been performed to compare the photostability of different cobalamins under UVA exposure. Their indirect photodegradation due to their antioxidant properties and their photostability in vivo have also not been studied so far. The photodegradation of four cobalamins (methylcobalamin (MeCbl), adenosylcobalamin (AdCbl), hydroxocobalamin (OHCbl) and cyanocobalamin (CNCbl)) under UVA exposure in aqueous solutions (pH=7.4) have been investigated by absorption spectroscopy. The photodegradation of OHCbl in the absence and presence of the endogenous photosensitizer riboflavin was studied. Serum vitamin B12 concentrations before and after summer were measured in four patients with psoriasis. All studied cobalamins are photolabile. The biologically active forms of cobalamin, AdCbl and MeCbl, are converted to OHCbl within seconds during UVA exposure. OHCbl is the most stable cobalamin. However, reactive oxygen species increases the degradation rate of OHCbl. Our pilot study on humans demonstrates that serum vitamin B12 concentrations are not significantly affected during summertime in Norway. Further work is needed to determine vitamin B12 photostability in humans living at lower latitudes or using sunbeds.

Cobalamin status in children

Cobalamin and the metabolic markers methylmalonic acid and total homocysteine undergo marked changes during childhood. In breastfed infants a metabolic profile indicative of cobalamin deficiency is common. Symptoms of cobalamin deficiency in children differ with age, presenting a continuum from subtle developmental delay to life-threatening clinical conditions. The symptoms may be difficult to detect, particularly in infants, and there tends to be a diagnostic delay of several months in this age group. Several reports show that even moderate deficiency in children may be harmful, and long-term consequences of neurological deterioration may persist after cobalamin deficiency has been treated. Given the crucial role of cobalamin for normal growth and development, possible widespread infantile deficiency needs attention. Cobalamin deficiency should be considered a differential diagnosis in children with subtle symptoms, and strategies to prevent cobalamin deficiency in mothers and children should be addressed.

The critical role of vitamin B12

Vitamin B12 affects the peripheral and central nervous systems, bone marrow, skin and mucous membranes, bones, and vessels, as well as the normal development of children. Although there is undoubtedly an association between vitamin B12 and homocysteinemia, their relative influence on cardiovascular events is controversial. Some large studies confirm that a supplementation with group B vitamins did not reduce the risk of major cardiovascular events or all-cause mortality in patients with vascular disease. The outcomes of these and similar trials could have been different had the researchers considered the following points: Using vitamin B12 or B-complex as secondary prevention of cardiovascular events for patients with irreversible changes of blood vessels is probably in error. Rather, vitamin B12 or B-complex should be used as primary prevention. Also, using high doses of vitamin B12 will probably be more effective than using low doses of "group B vitamins" The effect of vitamin B12 on the proliferation of malignant cells has been examined in vivo and in vitro in numerous studies. Their results indicate that methylcobalamin inhibits the proliferation of malignant cells and propose the possibility of methylcobalamin as a candidate of potentially useful agents for the treatment for some malignant tumors. There are many articles indicating the increasing prevalence of low vitamin B12 level in different segments of general population. In order to prevent serious health problems, vitamin B12 routine fortification should be seriously considered and discussed.

KEYWORDS

vitamin B12; homocysteine; malignancy; vitamin B12 routine fortification; recurrent aphthous stomatitis.

Cutaneous manifestations of nutritional deficiency

PURPOSE OF REVIEW

Nutritional deficiency, a global problem, remains uncommon in developed nations. Associated morbidity and mortality make it imperative that clinicians remain familiar with the clinical signs and symptoms of nutritional deficiencies to facilitate diagnosis. This article will review the cutaneous findings and recent literature regarding B12, niacin, zinc, vitamin A, kwashiorkor, biotin and selenium deficiencies, along with the clinical entities of noma and phrynoderma.

RECENT FINDINGS

Much of our understanding of the clinical manifestations of nutritional deficiencies comes from old literature; however, recent case reports and series have highlighted several patient populations that may be at risk from acquired deficiencies, including patients with anorexia nervosa, cystic fibrosis, patients receiving long-term tube-feeding and those with perceived or real food allergy. There can be significant clinical overlap between various micronutrient, protein and vitamin deficiencies. Additionally, providers should consider the possibility of multiple deficiencies coexisting in individual patients.

SUMMARY

Reports of nutritional deficiency continue to surface in developed nations and pediatricians need to have a basic understanding of their clinical manifestations. The skin is commonly affected and can be the presenting sign of illness. A higher clinical suspicion needs to be maintained in certain populations.

Vitamin B12 Could be A "Master Key" in the Regulation of Multiple Pathological Processes

Multifunctional systems must maintain homeostasis. Man is an ideal example of a system that constantly aspires to attain optimal regulation, even under the stress of severe disease. We assume that there are universal, interchangeable (as required) biologically active substances that regulate the system and try to keep it in balance. We propose that one of these substances is vitamin B12. Why vitamin B12? The list of organs and body systems in which vitamin B12 plays a functional role is constantly being added to. Vitamin B12 affects the normal growth of children, the peripheral and central nervous systems, bone marrow, skin, mucous membranes, bones, and vessels. It is possible that even when the serum cobalamin level is normal, treatment with vitamin B12 could correct defects caused by other biologically active substances. We call this phenomenon the "Master Key" effect. We suggest that this "Master Key" concept can be tested by treating diseases, such as recurrent stomatitis, various forms of hyperpigmentation, trophic ulcers, and burns, with vitamin B12, even if the B12 serum level is normal.

A treatable cause of ataxia in children

An 11-year-old black male presenting with severe subacute sensory ataxia, unusual skin hyperpigmentation, megaloblastic anemia, low serum B12 levels, and an abnormal part I Schilling test was diagnosed with pernicious anemia in the context of a polyglandular syndrome. Intrinsic factor and thyroid microsomal antibodies were positive, and thyroid-stimulating hormone levels were undetectable. There was a strong familial aggregation because the mother, a maternal aunt, the maternal grandfather, and the maternal great-grandmother had been diagnosed with pernicious anemia, albeit of unspecified etiology. Spinal magnetic resonance imaging (MRI) demonstrated extensive demyelination of the posterior columns along the entire length of the cord, as well as areas of contrast enhancement. Treatment with cobalamin produced complete remission of the neurologic deficits and normalization of the MRI findings in the short space of 2 months. Although rare, childhood pernicious anemia is a treatable disease that should be included in the differential diagnosis of the sensory ataxias in children. In this article, we review the causes of pernicious anemia in children and discuss the MRI findings.