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Biomedical subjects

D J Atherton

Publications and source records attributed to D J Atherton.

At least 19 recordsLinked to original sources

Nephro-urological complications of epidermolysis bullosa in paediatric patients.

A small but important proportion of patients with epidermolysis bullosa (EB) may develop significant renal and urological complications which can have a major impact on their morbidity and mortality. During the last 10 years, five of a large group of children with EB under our care, with either dystrophic or junctional types of disease, experienced major nephro-urological complications. Two patients with recessive dystrophic EB (REDB) developed macroscopic haematuria - one had renal failure and underwent a renal biopsy showing IgA nephropathy. A third patient with RDEB also developed renal failure and his biopsy demonstrated postinfectious glomerulonephritis/type III membranoproliferative (mesangiocapillary) glomerulonephritis. Both patients with renal failure underwent peritoneal dialysis. Two patients with junctional EB developed obstructive uropathies, which required bladder reconstruction and the fashioning of a Mitrofanoff channel in one.

Adolescent↗

Thalidomide in the management of epidermolysis bullosa pruriginosa.

Epidermolysis bullosa (EB) pruriginosa is a distinctive clinical subtype of dystrophic EB. We report a patient with dominant dystrophic EB pruriginosa, who had an excellent response to systemic thalidomide treatment. The mechanism of action of thalidomide in the management of pruriginous disorders is not yet completely understood. Most recent studies point towards an immunomodulatory action of thalidomide that may suppress excessive production of tumour necrosis factor-alpha and may downregulate certain cell surface adhesion molecules involved in leucocyte migration.

Adolescent↗

Atypical epidermolytic palmoplantar keratoderma presentation associated with a mutation in the keratin 1 gene.

BACKGROUND: Epidermolytic palmoplantar keratoderma (EPPK) is an autosomal dominant genodermatosis characterized by epidermolytic hyperkeratosis strictly confined to the palms and soles, and usually associated with mutations in the keratin K9 gene (KRT9). Mutations in the keratin K1 gene (KRT1) have been shown to underlie a variety of phenotypes typically involving generalized epidermolytic hyperkeratosis, but in some cases the phenotype can be more regionally restricted. OBJECTIVES: To identify the genetic defect in two unrelated families initially presenting with EPPK but where careful examination revealed hyperkeratosis extending on to the proximal wrist flexure. Methods Linkage analysis and DNA sequencing. RESULTS: We found that this phenotype is caused by a heterozygous missense mutation in the K1 gene, designated I479T. This mutation lies in the highly conserved helix termination motif of K1, previously shown to be important for keratin assembly and filament formation. In general, mutations in this region of keratins are associated with more severe disease phenotypes. However, K1 mutations in this region and the I479T mutation in particular have previously been associated with both severe and mild bullous congenital ichthyosiform erythroderma phenotypes. When further clinical enquiries were made, several affected individuals in the families studied here were found to have had transient flexural peeling and hyperkeratosis in the neonatal period. CONCLUSIONS: K1 mutations may underlie a phenotype closely resembling EPPK. A history of transient flexural peeling and hyperkeratosis in childhood and palmoplantar keratoderma which extends beyond the boundary of the palmoplantar margins may indicate a K1 mutation rather than a K9 defect. As K1 mutations are also associated with severe widespread phenotypes, with important implications for prognostic and genetic counselling, whole body examination is recommended for patients presenting with EPPK.

Chromosome Mapping↗

Hay-Wells syndrome is caused by heterozygous missense mutations in the SAM domain of p63.

Hay-Wells syndrome, also known as ankyloblepharon-ectodermal dysplasia-clefting (AEC) syndrome (OMIM 106260), is a rare autosomal dominant disorder characterized by congenital ectodermal dysplasia, including alopecia, scalp infections, dystrophic nails, hypodontia, ankyloblepharon and cleft lip and/or cleft palate. This constellation of clinical signs is unique, but some overlap can be recognized with other ectodermal dysplasia syndromes, for example ectrodactyly--ectodermal dysplasia--cleft lip/palate (EEC; OMIM 604292), limb--mammary syndrome (LMS; OMIM 603543), acro-dermato-ungual-lacrimal-tooth syndrome (ADULT; OMIM 103285) and recessive cleft lip/palate--ectodermal dysplasia (CLPED1; OMIM 225060). We have recently demonstrated that heterozygous mutations in the p63 gene are the major cause of EEC syndrome. Linkage studies suggest that the related LMS and ADULT syndromes are also caused by mutations in the p63 gene. Thus, it appears that p63 gene mutations have highly pleiotropic effects. We have analysed p63 in AEC syndrome patients and identified missense mutations in eight families. All mutations give rise to amino acid substitutions in the sterile alpha motif (SAM) domain, and are predicted to affect protein--protein interactions. In contrast, the vast majority of the mutations found in EEC syndrome are amino acid substitutions in the DNA-binding domain. Thus, a clear genotype--phenotype correlation can be recognized for EEC and AEC syndromes.

Abnormalities, Multiple↗

Genomic localization, organization and amplification of the human zinc transporter protein gene, ZNT4, and exclusion as a candidate gene in different clinical variants of acrodermatitis enteropathica.

Acrodermatitis enteropathica is an inherited disorder of zinc metabolism, the molecular basis of which is currently unknown. Recent transgenic mouse studies have highlighted the potential significance of certain zinc transport proteins, for example ZnT4, in providing clues to the pathogenesis of zinc-related disorders such as acrodermatitis enteropathica. Specifically, mice of any genotype suckled on ZnT4-deficient mice fail to absorb intestinal zinc and ZnT4-deficient mice also develop dermatitis, alopecia and stunted growth. Therefore, to assess human ZnT4 as a candidate gene/protein in acrodermatitis enteropathica or related disorders, we characterized the intron-exon organization of the human ZNT4 gene, which comprises seven distinct exons spanning approximately 38.7 kb. High-resolution radiation hybrid mapping placed ZNT4 on 15q21.1. We also developed a PCR-based mutation detection strategy using primers placed on flanking introns followed by direct sequencing of the PCR products. Using this approach, we sequenced DNA from five individuals with acrodermatitis enteropathica; no mutations were identified. Thus, ZNT4 is unlikely to be the correct candidate gene for this disorder. We also identified and characterized two common single nucleotide polymorphisms in exon 5 and in the 3' UTR of ZNT4, which will be useful for future genetic linkage studies in assessing ZNT4 as a candidate gene for other inherited disorders of zinc metabolism.

Acrodermatitis↗

The aetiology and management of irritant diaper dermatitis.

Irritant diaper dermatitis (IDD) is a common condition caused by the combination of wearing diapers, and incontinence of urine and faeces. The available evidence suggests that maceration of the stratum corneum by water increases susceptibility to frictional damage, and epidermal permeation of irritants. The most important irritants underlying IDD appear to be digestive enzymes persisting in faeces, particularly when these are activated by a high pH.

Administration, Topical↗

Central nervous system imaging and congenital melanocytic naevi.

AIM: To establish the prevalence of central nervous system (CNS) abnormalities on magnetic resonance imaging (MRI) in a population of children with congenital melanocytic naevi (CMN) over the head and/or spine, and to compare this with clinical findings. METHODS: Forty three patients identified from outpatient clinics underwent MRI of the brain and/or spine. These were reported by a paediatric radiologist and findings compared with the clinical picture. RESULTS: Nine patients had abnormal clinical neurology, seven had abnormal findings on MRI, and six had both abnormal clinical and radiological findings. Only three of the abnormal MRIs showed features of intracranial melanosis. Three others showed structural brain abnormalities: one choroid plexus papilloma, one cerebellar astrocytoma, and one posterior fossa arachnoid cyst; the first two of these have not previously been described in association with CMN. The last abnormal MRI showed equivocal changes requiring reimaging. CONCLUSIONS: The prevalence of radiological CNS abnormality in this group of children was 7/43. Six of these developed abnormal clinical neurological signs within the first 18 months of life, but two did not do so until after the MRI. Two of the CNS lesions were operable; for this reason we support the routine use of early MRI in this group.

Adolescent↗

Laryngeal involvement in the Dowling-Meara variant of epidermolysis bullosa simplex with keratin mutations of severely disruptive potential.

The clinical features of the Dowling-Meara variant of epidermolysis bullosa simplex (EBS-DM) can, in an infant, be indistinguishable from other severe forms of epidermolysis bullosa (EB). Two unrelated infants with no family history of skin disease are described who, within hours of birth, developed extensive blistering of skin and oral mucosae and who both subsequently developed hoarse cries. Despite this superficial resemblance to other forms of EB, electron microscopy revealed a basal cell rupture and keratin aggregates characteristic of EBS-DM in the skin of both infants and in the vocal cord epithelium of one. Molecular analysis confirmed the diagnosis by identification of mis-sense point mutations in basal cell keratin genes in both cases. One patient carries a point mutation in keratin 14 (converting arginine at position 125 to histidine) and the other has a novel point mutation in keratin 5 (converting serine at position 181 to proline). Hoarseness is not a well documented feature of EBS-DM and is usually associated with junctional EB. These two patients demonstrate that the presence of a hoarse cry in an infant affected by severe EB does not necessarily indicate a poor prognosis.

DNA Mutational Analysis↗

Gastrointestinal symptoms in patients with asthma.

AIMS: Minor gastrointestinal abnormalities have been reported in children with asthma, but the prevalence of gastrointestinal symptoms in these children has not been studied. METHODS: 75 children with bronchial asthma and an age and sex matched control group were recruited. Parents completed a questionnaire on gastrointestinal symptoms and on asthma. Weight and height were measured; a clinical evaluation of asthma was undertaken and skin prick tests were performed. RESULTS: Children with asthma had a significantly greater frequency of gastrointestinal symptoms, particularly diarrhoea, vomiting, and abdominal pain, than did controls. Gastrointestinal symptoms were slightly more common in children with atopic symptoms other than asthma, or with positive skin prick tests to foods. There was no association between current gastrointestinal symptoms and medications or attacks of asthma. CONCLUSIONS: The occurrence of gastrointestinal symptoms appears to be common in children with asthma. These symptoms might be caused by an atopic gastroenteropathy, which might play a part in the pathogenesis of asthma in some cases.

Adolescent↗

Childhood dermatitis herpetiformis: an unusual presentation.

Childhood dermatitis herpetiformis (DH) is rare. The true prevalence and incidence of this condition are unknown. We report a 7-year-old boy presenting with nonpruritic inflammatory papules on the buttocks and extensor surfaces, clinico-pathologically consistent with Sweet's neutrophilic dermatosis. Immunofluorescence studies showed IgA deposits in the dermal papillae consistent with DH. Remission was achieved with a gluten-free diet and dapsone. Childhood DH may present different clinical signs to the adult form and misdiagnosis can occur if immunofluorescence is not requested on skin biopsy.

Anti-Inflammatory Agents, Non-Steroidal↗

Allelic heterogeneity of dominant and recessive COL7A1 mutations underlying epidermolysis bullosa pruriginosa.

The inherited mechanobullous disease, dystrophic epidermolysis bullosa, is caused by type VII collagen gene (COL7A1) mutations. We studied six unrelated patients with a distinct clinical subtype of this disease, epidermolysis bullosa pruriginosa, characterized by pruritus, excoriated prurigo nodules, and skin fragility. Mutation analysis using polymerase chain reaction amplification of genomic DNA, heteroduplex analysis and direct nucleotide sequencing demonstrated pathogenetic COL7A1 mutations in each case. Four patients had a glycine substitution mutation on one COL7A1 allele (G1791E, G2242R, G2369S, and G2713R), a fifth was a compound heterozygote for a splice site mutation (5532 + 1G-to-A) and a single base pair deletion (7786delG), and a sixth patient was heterozygous for an out-of-frame deletion mutation (6863del16). This study shows that the molecular pathology in patients with the distinctive clinical features of epidermolysis bullosa pruriginosa is heterogeneous and suggests that other factors, in addition to the inherent COL7A1 mutation(s), may be responsible for an epidermolysis bullosa pruriginosa phenotype.

Adolescent↗

A new syndrome of spondyloepimetaphyseal dysplasia, eczema and hypogammaglobulinaemia.

We describe a female infant with a combination of very short stature, severe eczema and IgG deficiency causing recurrent infections in infancy. The radiological features of this condition are presented in the neonatal period, at the age of 5 months and at 2 years and 6 months. We propose that this condition is a previously undescribed type of spondyloepimetaphyseal dysplasia.

Agammaglobulinemia↗

Prognostic implications of determining 180 kDa bullous pemphigoid antigen (BPAG2) gene/protein pathology in neonatal junctional epidermolysis bullosa.

Epidermolysis bullosa (EB) in neonates is often difficult to characterize, both in terms of making a precise diagnosis and in being able to comment accurately on the prognosis for the affected child. We present a case of a neonate with inherited mucocutaneous fragility and failure to thrive and detail our laboratory approach for classifying the subtype of EB in this child. Mutational analysis revealed a homozygous non-sense mutation in the gene encoding the 180 kDa bullous pemphigoid antigen, also known as type XVII collagen, predicting a non-lethal form of junctional EB. Identification of the underlying molecular pathology in this case was of use in improving diagnosis, classification, management and counselling.

Autoantigens↗