65Zinc absorption in patients suffering from acrodermatitis enteropathica and in normal adults assessed by whole-body counting technique

Atopic Dermatitis-like Genodermatosis: Disease Diagnosis and Management

Eczema is a classical characteristic not only in atopic dermatitis but also in various genodermatosis. Patients suffering from primary immunodeficiency diseases such as hyper-immunoglobulin E syndromes, Wiskott-Aldrich syndrome, immune dysregulation, polyendocrinopathy, enteropathy, X-linked syndrome, STAT5B deficiency, Omenn syndrome, atypical complete DiGeorge syndrome; metabolic disorders such as acrodermatitis enteropathy, multiple carboxylase deficiency, prolidase deficiency; and other rare syndromes like severe dermatitis, multiple allergies and metabolic wasting syndrome, Netherton syndrome, and peeling skin syndrome frequently perform with eczema-like lesions. These genodermatosis may be misguided in the context of eczematous phenotype. Misdiagnosis of severe disorders unavoidably affects appropriate treatment and leads to irreversible outcomes for patients, which underlines the importance of molecular diagnosis and genetic analysis. Here we conclude clinical manifestations, molecular mechanism, diagnosis and management of several eczema-related genodermatosis and provide accessible advice to physicians.

Zinc and infant nutrition

Zinc is essential for a wide variety of cellular processes in all cells. It is a critical dietary nutrient, particularly in the early stages of life. In the early neonatal period, adequate sources of zinc can be obtained from breast milk. In rare circumstances, the mammary gland produces zinc deficient milk that is potentially lethal for exclusively breast-fed infants. This can be overcome by zinc supplementation to the infant. Alterations to key zinc transporters provide insights into the mechanisms of cellular zinc homeostasis. The bioavailability of zinc in food depends on the presence of constituents that may complex zinc. In many countries, zinc deficiency is a major health issue due to poor nourishment. Young children are particularly affected. Zinc deficiency can impair immune function and contributes to the global burden of infectious diseases including diarrhoea, pneumonia and malaria. Furthermore, zinc deficiency may extend its influence across generations by inducing epigenetic effects that alter the expression of genes. This review discusses the significance of adequate zinc nutrition in infants, factors that influence zinc nutrition, the consequences of zinc deficiency, including its contribution to the global burden of disease, and addresses some of the knowledge gaps in zinc biology.

Intracellular signalling during female gametogenesis

Female reproductive potential is dictated by the size of the primordial follicle pool and the correct regulation of oocyte maturation and activation--events essential for production of viable offspring. Although a substantial body of work underpins our understanding of these processes, the molecular mechanisms of follicular and oocyte development are not fully understood. This review summarizes recent findings which have improved our conception of how folliculogenesis and oocyte competence are regulated, and discusses their implications for assisted reproductive techniques. We highlight evidence provided by genetically modified mouse models and in vitro studies which have refined our understanding of Pi3k/Akt and mTOR signalling in the oocyte and have discovered a role for Jak/Stat/Socs signalling in granulosa cells during primordial follicle activation. We also appraise a novel role for the metal ion zinc in the regulation of meiosis I and meiosis II progression through early meiosis inhibitor (Emi2) and Mos-Mapk signalling, and examine studies which expand our understanding of intracellular calcium signalling and extrinsic Plcζ in stimulating oocyte activation.

Zinc deficiency and its inherited disorders -a review

Zinc is an essential trace element required by all living organisms because of its critical roles both as a structural component of proteins and as a cofactor in enzyme catalysis. The importance of zinc in human metabolism is illustrated by the effects of zinc deficiency, which include a diminished immune response, reduced healing and neurological disorders. Furthermore, nutritional zinc deficiency can be fatal in newborn or growing animals. While zinc deficiency is commonly caused by dietary factors, several inherited defects of zinc deficiency have been identified. Acrodermatitis enteropathica is the most commonly described inherited condition found in humans. In several of the few cases that have been reported, this disorder is associated with mutations in the hZIP4 gene, a member of the SLC39 family, whose members encode membranebound putative zinc transporters. Mutations in other members of this family or in different genes may account for other cases of acrodermatitis in which defects in hZIP4 have not been detected. Another inherited form of zinc deficiency occurs in the lethal milk mouse, where a mutation in ZnT4 gene, a member of the SLC30 family of transmembrane proteins results in impaired secretion of zinc into milk from the mammary gland. A similar disorder to the lethal milk mouse occurs in humans. In the few cases studied, no changes in ZnT4 orthologue, hZnT4, were detected. This, and the presence of several minor phenotypic differences between the zinc deficiency in humans and mice, suggests that the human condition is caused by defects in genes that are yet to be identified. Taking into account the fact that there are no definitive tests for zinc deficiency and that this disorder can go undiagnosed, plus the recent identification of multiple members of the SCL30 and SLC39, it is likely that mutations in other genes may underlie additional inherited disorders of zinc deficiency.

Acquired acrodermatitis enteropathica due to zinc deficiency in a patient with pre-existing Darier's disease

BACKGROUND

Acrodermatitis enteropathica is characterised by inflamed patches of dry red skin which then become crusted and blistered before revealing a pustulent eroded lesion. Typically these patches start near the body's orifices before migrating to other sites, however in this patient the presentation was atypical thus delaying the diagnosis.

OBSERVATIONS

We report a case of an atypical presentation of acrodermatitis enteropathica (AE) due to acquired zinc deficiency in a 65 year old female patient with a previous diagnosis of histologically confirmed Darier's disease. This patient's rash began on the limbs and trunk before progressing to include the perineum, oral mucosa and nose. Diffuse loss of hair on scalp, eyebrows and eyelashes was observed. Acrodermatitis enteropathica typically presents in infants, either due to an autosomal recessive genetic disorder, or after the cessation of breast feeding. In adults acquired zinc deficiency can be caused by glucagonoma syndrome, poor nutritional state, intestinal malabsorption, nephrotic syndrome and after major trauma (i.e. burns or significant surgery). In our patient low zinc levels confirmed hypozincaemia and the diagnosis of acrodermatitis enteropathica. The patient started oral zinc replacement. Within a few days her symptoms began to improve, and her hair has started to grow.

CONCLUSION

We believe this to be an unusual presentation of acrodermatitis enteropathica due to a probable dietary zinc deficiency in a lady with pre-existing Darier's disease which may possibly have influenced the uncharacteristic clinical presentation.

An update on mutations of the SLC39A4 gene in acrodermatitis enteropathica

Acrodermatitis enteropathica (AE) is a very rare inherited recessive disease caused by severe zinc deficiency. It typically occurs in early infancy and is characterized by periorificial and acral dermatitis, alopecia, and diarrhea. In 2002, both we and others identified the AE SLC39A4 gene located at 8q24.3, and described the first causative mutations for the disease. The SLC39A4 gene encodes a zinc-specific transporter belonging to the Zinc/Iron-regulated transporter-like family, which is highly expressed in the duodenum and jejunum. The SLC39A4 mutations are spread over the entire gene and include many different types of mutations. We report here the identification of five novel variants, including three likely pathogenic mutations. Since the first description, 31 mutations or unclassified variants of SLC39A4 have been reported in this gene. Although most of the patients with AE carry homozygous or compound heterozygous mutations, some of them have either no SLC39A4 mutation or only a monoallelic mutation. Thus, a genotype-phenotype correlation is not easily defined for all AE patients, and the molecular basis of the disease could be more complex than previously described. In cases unexplained by current genetic analyses, the most plausible molecular causes could be a dysregulation of the SLC39A4 gene transcription -- involving either metal response elements (MREs) or a modifier gene -- or the existence of another putative AE gene. In this review, we summarize the current knowledge of SLC39A4 mutations, as well as the future prospects to fully unravel the pathogenesis of AE.

The Mammalian Zip5 Protein Is a Zinc Transporter That Localizes to the Basolateral Surface of Polarized Cells

The mouse and human Zip5 proteins are members of the ZIP family of metal ion transporters. In this study, we present evidence that mouse Zip5 is a zinc uptake transporter that is specific for Zn(II) over other potential metal ion substrates. We also show that, unlike many other mammalian ZIP proteins, the endocytic removal of mZip5 from the plasma membrane is not triggered by zinc treatment. Thus, the activity of mZip5 does not appear to be down-regulated by zinc repletion. Zip5 expression is restricted to many tissues important for zinc homeostasis, including the intestine, pancreas, liver, and kidney. Zip5 is similar in sequence to the Zip4 protein, which is involved in the uptake of dietary zinc. Co-expression of Zip4 and Zip5 in the intestine led to the hypothesis that these proteins play overlapping roles in the uptake of dietary zinc across the apical membrane of intestinal enterocytes. Surprisingly, however, we found that mZip5 localizes specifically to the basolateral membrane of polarized Madin-Darby canine kidney cells. These observations suggest that Zip5 plays a novel role in polarized cells by carrying out serosal-to-mucosal zinc transport. Furthermore, given its expression in tissues important to zinc homeostasis, we propose that Zip5 plays a central role in controlling organismal zinc status.

A novel member of a zinc transporter family is defective in acrodermatitis enteropathica

The rare inherited condition acrodermatitis enteropathica (AE) results from a defect in the absorption of dietary zinc. Recently, we used homozygosity mapping in consanguineous Middle Eastern kindreds to localize the AE gene to an approximately 3.5-cM region on 8q24. In this article, we identify a gene, SLC39A4, located in the candidate region and, in patients with AE, document mutations that likely lead to the disease. The gene encodes a histidine-rich protein, which we refer to as "hZIP4," which is a member of a large family of transmembrane proteins, some of which are known to serve as zinc-uptake proteins. We show that Slc39A4 is abundantly expressed in mouse enterocytes and that the protein resides in the apical membrane of these cells. These findings suggest that the hZIP4 transporter is responsible for intestinal absorption of zinc.

Homozygosity mapping places the acrodermatitis enteropathica gene on chromosomal region 8q24.3

Acrodermatitis enteropathica (AE) is a rare autosomal recessive pediatric disease characterized by dermatitis, diarrhea, alopecia, and growth failure. The disease results from insufficient uptake of zinc by the intestine and can be fatal unless the diet is supplemented with zinc. To map the gene responsible for AE, a genomewide screen was performed on 17 individuals, including 4 affected individuals, in a consanguineous Jordanian family. Three markers-D8S373, D10S212, and D6S1021-had a pattern consistent with tight linkage to a recessive disease: one allele in the affected sibs and multiple alleles in unaffected sibs and parents. Two-point parametric linkage analysis using FASTLINK identified one region, D8S373, with a maximum LOD score >1.5 (1.94 at D8S373: recombination fraction.001). Twelve additional markers flanking D8S373 were used to genotype the extended family, to fine-map the AE gene. All five affected individuals-including one who was not genotyped in the genomewide screen-were found to be homozygous for a common haplotype, spanning approximately 3.5 cM, defined by markers D8S1713 and D8S2334 on chromosomal region 8q24.3. To support these mapping data, seven consanguineous Egyptian families with eight patients with AE were genotyped using these markers, and six patients from five families were found to be homozygous in this region. Multipoint analysis with all consanguineous families, by Mapmaker/Homoz, resulted in a maximum LOD score of 3.89 between D8S1713 and D8S373. Sliding three-point analysis resulted in a maximum LOD score of 5.16 between markers D8S1727 and D8S1744.

65 zinc absorption in patients with insulin-dependent diabetes mellitus assessed by whole-body counting technique

The gastrointestinal absorption of zinc was measured in patients with insulin-dependent diabetes mellitus. The concentration of zinc in serum was similar to healthy individuals. However the urinary excretion rate of zinc relative to the creatinine excretion, was approximately doubled (p less than 0.001) in the diabetics. The absorption of 65Zn tended to be lower in diabetics, but did not reach the level of statistical significance (retention percent 30.6 versus 42.6 (p greater than 0.10). A hypothesis of intracellular zinc depletion with time in insulin-dependent diabetics is proposed.

Zinc transport by fibroblasts from patients with acrodermatitis enteropathica

Acrodermatitis enteropathica (AE) is a zinc deficiency disease. To date, the only defect has been demonstrated in the gut. We have investigated zinc uptake in fibroblasts established from four unrelated patients with AE using normal skin fibroblasts as controls. Zinc content of AE and control cells was similar (0.3 fmol/cell). Zinc accumulation over 24 h from a complete culture medium was similar in both normal controls and mutant cells. The fraction of zinc removed by Pronase treatment remained constant at 50 pmol/micrograms DNA, whereas the zinc remaining after Pronase treatment accumulated rapidly for 8 h, then more slowly. Analysis of binding data showed no significant difference between AE and control cells, with apparent Ka values of 4-6 X 10(6) M-1 and between 1 and 2 X 10(8) receptors/cell. Analysis of Pronase resistant data showed no difference between the control and the mutant cells with apparent Km values of 0.2-0.3 microM and Vmax values of 17-19 pmol/micrograms DNA/h. No difference in zinc efflux rates was detected. We conclude that the defect that underlies acrodermatitis enteropathica is either not expressed in fibroblasts or cannot be detected under these experimental conditions.

Clinical and laboratory diagnosis of acrodermatitis enteropathica

Acrodermatitis enteropathica is an inborn error of metabolism resulting in zinc malabsorption and severe zinc deficiency. From personal experience and a literature review the following conclusions were drawn: 1. Symptoms other than dermatitis, vary with age. Diarrhoea, mood changes, anorexia, and neurological disturbance were reported most frequently in infancy. Growth retardation, alopecia, weight loss and recurrent infections were prevalent in toddlers and schoolchildren. Spontaneous remission may occur at adolescence. 2. The severity of symptoms also varies. Intermittent or mild cases of the disease and those presenting with uncommon features such as ophthalmic, cerebral or hepatic involvement, are easily overlooked. In the severe cases this may result in a fatal outcome. If untreated, the overall mortality rate is 20%, being higher in males. 3. The laboratory diagnosis is hazardous. In patients, mean zinc values in serum, urine and hair were ca. 50% of normal levels. There is a 15% overlap with healthy controls; moreover, low zinc levels in serum, urine or hair are also found in other diseases. A more specific test is required. 4. In cases of doubt, in vitro or in vivo zinc absorption tests using radioisotopes (65Zn or 69mZn) may be performed. These appear not to be influenced by other conditions and show less overlap with controls. If such tests are unavailable, the clinical response to 3-30 mumol zinc/kg per day for 5 days may be awaited. This is recommended in infants or children with one or more symptoms of acrodermatitis enteropathica.

Zinc absorption in patients with compensated alcoholic cirrhosis

Zinc absorption was measured by whole-body counting in 10 patients with compensated alcoholic cirrhosis without steatorrhoea and in 8 healthy subjects. After oral administration of 65Zn the absorption was measured at regular intervals until a straight time/activity retention curve was obtained in a semilogarithmic system, whereafter it was calculated by extrapolation to time zero. Cirrhotic patients had a median absorption of 69% (27-90%), compared with 42% (25-67%) in healthy subjects (P less than 0.01). Median T1/2 of 65Zn as calculated from the retention curve was 156 days (83-280 days) in cirrhotic patients and 103 days (72-132 days) in healthy subjects (P less than 0.05). Median serum zinc value was 11 mumol/l (9-17 mumol/l) in cirrhotic patients and 16 mumol/l (12-17 mumol/l) in healthy subjects (P less than 0.01). Median erythrocyte zinc value was 224 mumol/l (205-281 mumol/l) in cirrhotics and 223 mumol/l (188-275 mumol/l) in healthy subjects (P less than 0.1). Six cirrhotic patients, of whom four took diuretics, had increased urinary zinc excretion (greater than 15 mumol/24 h). Zinc absorption seems intact in compensated alcoholic cirrhosis. The increased absorption and prolonged T1/2 of 65Zn might be compensatory to a moderate zinc depletion.

Acrodermatitis enteropathica

A case of acrodermatitis enteropathica belatedly recognized in a pregnant 23-year-old woman is reported. The condition was not specifically diagnosed during childhood. It cleared at puberty but recurred during two of three pregnancies in the form of pustular, vesiculobullous, and psoriasiform lesions. There were no associated signs or symptoms in other organs. Initial diagnoses upon the recurrence during the third pregnancy were herpes gestationis and impetigo herpetiformis. A markedly decreased serum zinc level (18 micrograms/dl) was found. Treatment with zinc sulfate was instituted, and within 3 days the cutaneous lesions began to clear. Two months after the birth of a healthy child, and without further therapy, all lesions had resolved and the serum zinc level was nearly normal. Acrodermatitis enteropathica should be considered in the differential diagnosis of unresponsive bullous dermatoses occurring during pregnancy.

Acrodermatitis enteropathica

A brief review of the clinical and biochemical features of Acrodermatitis enteropathica is given. This condition in now known to be caused by a systemic zinc deficiency secondary to a defect in the intestinal absorption of zinc and it illustrates the metabolic importance of this element in man.

Serum zinc in acne vulgaris

Serum zinc levels in acne patients and in matched healthy controls of both sexes and within the same age group (16-20 years age) were estimated. Women, whether diseased or healthy, have shown a significantly lower mean serum zinc level than the corresponding men. In advanced grades of acne, both men and women have a significantly lower level than the corresponding control groups. Within the same sex group, those with advanced grades have revealed a significantly lower level than those with slight grades.

Malignant melanoma and dermatofibrosarcoma in a 60-year-old patient with lifelong acrodermatitis enteropathica

The life course of acrodermatitis enteropathica is recorded in a 62-year-old white man. Initially saved in infancy by breast-feeding and good medical care, later in his twenties he responded well to diiodohydroxyquinoline (Diodoquin) therapy, his only residua being dermatitis, hoarseness, and short stature. Subsequently untreated, this patient years later developed not only a dermatofibrosarcoma but also a large amelanotic malignant melanoma. Both were successfully excised. Subsequently, oral zinc therapy initiated for the first time cleared his acrodermatitis, which had been present for 60 years. It is suggested that this patient's malignancies developed as a result of an immune deficiency state typically found in acrodermatitis enteropathica. On this basis, acrodermatitis enteropathica may be viewed as having a malignant potential over the long term. The zinc-dependent nature of the immune deficit, however, suggests that lifelong daily zinc supplementation is an appropriate prophylactic measure.