Transient zinc deficiency syndrome in a breast-fed infant due to decreased zinc in breast milk (type II hypozincemia of infancy): A case report and review of the literature

Acquired Zinc Deficiency in Preterm Infant Post-Surgery for Necrotizing Enterocolitis (NEC) on Prolonged Total Parenteral Nutrition (TPN)

Zinc (Zn) is a vital trace element that plays a pivotal role in protein synthesis, cellular growth, and differentiation and is involved as a cofactor of metalloenzymes, performing a wide variety of metabolic, immune, and synthesis roles. Zn is required at all stages of an infant's and child's development, and severe Zn deficiency has been reported to lead to slower physical, cognitive, and sexual growth. Preterm neonates are at a higher risk of developing zinc deficiency for a variety of reasons, including low Zn intake from enteral feeds containing breast milk, relative malabsorption due to immaturity of the gastrointestinal tract with limited absorptive capacity, increased urinary loss of zinc, and increased demand during the early developmental stages. Moreover, premature infants are at risk of gastrointestinal diseases like necrotizing enterocolitis (NEC), which can limit absorption capacity and potentially lead to malabsorption. TPN is frequently used in preterm infants to provide them with sufficient nutrients and calories. However, it has its own complications, including cholestasis, especially if used for prolonged periods. In this case report, we are presenting the case of a male preterm infant who was delivered by caesarean section at 26 weeks' gestation. The baby developed an intestinal perforation due to NEC, for which he underwent surgery for resection of the necrotic bowel and the creation of a high ileal stoma and was put on prolonged total parenteral nutrition (TPN), which led to the development of zinc deficiency.

Analysis of similarities and differences between transient symptomatic zinc deficiency and acrodermatitis enteropathica in children: a case report of a Chinese Yi-ethnic infant

BACKGROUND

Transient symptomatic zinc deficiency (TSZD), an acquired type of zinc deficiency, is a rare, but probably underrecognized disease, extremely in breastfed premature with low birthweight infants. Its clinical manefestations are similar to Acrodermatitis enteropathica (AE), which is a genetic zinc absorption disorder caused by SLC39A4 gene mutations. This gene encodes a member of the zinc/iron-regulated transporter-like protein (ZIP) family. The encoded protein localizes to cell membranes and is required for zinc uptake in the intestine. TSZD is often misdiagnosed as AE because of their extremely similar manefestations, characterized by a typical rash. Therefore, the differention between them is still a clinical challenging.

CASE PRESENTATION

Here, we present a case of TSZD in a 4 month and 23 days female Chinese Yi-ethnic premature with AE-like skin lesions, mainly presenting periorificial, perianal and perineal crusted, eroded, erythemato-squamous eruption. Laboratory examination showed the patient's blood zinc level was significantly decreased. Further sequencing of the SLC39A4 gene showed no mutation in the infant and her parents. Skin lesions significantly improved after 6 days of initial zinc supplementation (3 mg/kg/d), and maintenance treatment with 1 mg/kg/day of zinc was discontinued after 8 months without recurrence.

CONCLUSIONS

The clinical manifestations of TSZD and AE are extremely similar, leading to a high rate of clinical misdiagnosis. While genetic analysis of the SLC39A4 gene is a reliable method for differentiating TSZD from AE. It is recommended that SLC39A4 gene test should be performed as far as possible in children with AE-like rash.

Acquired Zinc Deficiency Mimicking Acrodermatitis Enteropathica in a Breast-Fed Premature Infant

We present a case of a transient acquired zinc deficiency in a breast-fed, 4-month-old-male prematurely born infant, with acrodermatitis enteropathica-like symptoms such as crusted, eroded, erythemato-squamous eruption in periorificial and acral patterns. The laboratory investigations showed low zinc levels in the infant's and the mother's serum and in the mother's milk; genetic analysis did not show any mutation in the SLC39A4 gene, involved in acrodermatitis enteropathica. Acquired zinc deficiency is often found in premature infants because of their increased requirement, the low serum and milk zinc levels in breastfeeding women being also an important risk factor, as in this case. A prompt zinc supplementation is essential for the good prognosis of the disease.

Transient symptomatic zinc deficiency in an exclusively breastfed infant

A 3-month-old, full term female infant, adequate for gestational age, and exclusively breastfed, was admitted with a 10 day history of generalised scaling erythematous dermatitis, affecting the face (perinasal, nasolabial folds and periauricular), acral and intertriginous areas, with irritability and failure to thrive. Her mother had been treated with isoniazid since the third trimester because of family contact with tuberculosis. Based on a diagnosis of suspected impetiginised eczema, the infant was treated with flucloxacillin and prednisolone, and maternal isoniazid was suspended, with no improvement. Investigations found low serum zinc levels in the infant (33 μg/dL; normal range (NR) >60 μg/dL), normal plasma zinc levels in the mother (111.3 μg/dL; NR 68-120 μg/dL) and lower than the normal range of zinc levels in breast milk (270μg/L; NR 1000-2500 μg/L), suggesting acrodermatitis caused by zinc deficiency. Oral zinc supplementation (3 mg/kg/day) was started with a marked improvement in skin lesions, as well as good weight gain. At the age of 6 months, after food diversification, supplementation was suspended, without any recurrence of symptoms.

High proportion of transient neonatal zinc deficiency causing alleles in the general population

Loss of function (LoF) mutations in the zinc transporter SLC30A2/ZnT2 result in impaired zinc secretion into breast milk consequently causing transient neonatal zinc deficiency (TNZD) in exclusively breastfed infants. However, the frequency of TNZD causing alleles in the general population is yet unknown. Herein, we investigated 115 missense SLC30A2/ZnT2 mutations from the ExAC database, equally distributed in the entire coding region, harboured in 668 alleles in 60 706 healthy individuals of diverse ethnicity. To estimate the frequency of LoF SLC30A2/ZnT2 mutations in the general population, we used bioinformatics tools to predict the potential impact of these mutations on ZnT2 functionality, and corroborated these predictions by a zinc transport assay in human MCF-7 cells. We found 14 missense mutations that were markedly deleterious to zinc transport. Together with two conspicuous LoF mutations in the ExAC database, 26 SLC30A2/ZnT2 alleles harboured deleterious mutations, suggesting that at least 1 in 2334 newborn infants are at risk to develop TNZD. This high frequency of TNZD mutations combined with the World Health Organization-promoted increase in the rate of exclusive breastfeeding highlights the importance of genetic screening for inactivating SLC30A2/ZnT2 mutations in the general population for the early diagnosis and prevention of TNZD.

Longitudinal study on infants' temperament and physical development in Beijing, China

The objective of this longitudinal study is to explore the relationship between temperament and physical development among infants in Beijing, China. A total of 1117 term, normal and singleton infants were followed regularly for 12 months. Body weight and horizontal length were measured at 42 days and monthly from the third to twelfth month of their lives. Infants' temperament was assessed using the revised Chinese infants' temperament scale when the infants were 6 months. There was a significant difference on temperament dimensions between infants' genders (P < 0.05). Infants' weight and length were significantly related to their parents' weight and height. Infants with positive temperaments (easy and intermediate) were heavier than those with negative temperaments (difficult and slow to warm up) (P < 0.05). The horizontal length of boys was related to their temperament categories (P < 0.05). Infants' weight and length were significantly related to their temperament category and parents' weight and height.