Ectodermal Disorder Research Articles

Phenotypic heterogeneity in Woodhouse–Sakati syndrome: Two new families with a mutation in the C2orf37 gene

Hypogonadism, alopecia, diabetes mellitus, mental retardation, and extrapyramidal syndrome [also known as Woodhouse-Sakati syndrome (WSS)] is a rare autosomal recessive neuroendocrine and ectodermal disorder. The syndrome was first described by Woodhouse and Sakati in 1983, and 47 patients from 23 families have been reported so far. We report on an additional seven patients (four males and three females) from two highly consanguineous Arab families from Qatar, presenting with a milder phenotype of WSS. These patients show the spectrum of clinical features previously found in WSS, but lack evidence of diabetes mellitus and extrapyramidal symptoms. These two new families further illustrate the natural course and the interfamilial phenotypic variability of WSS that may lead to challenges in making the diagnosis. In addition, our study suggests that WSS may not be as infrequent in the Arab world as previously thought.

A new variant of ichthyosis follicularis with alopecia and photophobia (IFAP) syndrome with coexisting psoriasiform lesions and palmoplantar keratoderma. IFAP-PPK syndrome?

IFAP is an acronym for a rare congenital ectodermal disorder characterized by ichthyosis follicularis, alopecia and photophobia. A recessive X-linked mode of inheritance was initially proposed but recent reports in girls suggested genetic heterogeneity of this syndrome. We herein describe a 1-year-old boy with clinical features typical of IFAP syndrome plus psoriasis-like lesions and palmoplantar keratoderma (PPK).

A novel mutation in the connexin 26 gene (GJB2) in a child with clinical and histological features of keratitis–ichthyosis–deafness (KID) syndrome

Keratitis-ichthyosis-deafness (KID) syndrome is a rare congenital ectodermal disorder, caused by heterozygous missense mutation in GJB2, encoding the gap junction protein connexin 26. The commonest mutation is the p.Asp50Asn mutation, and only a few other mutations have been described to date. To report the fatal clinical course and characterize the genetic background of a premature male neonate with the clinical and histological features of KID syndrome. Genomic DNA was extracted from peripheral blood and used for PCR amplification of the GJB2 gene. Direct sequencing was used for mutation analysis. The clinical features included hearing impairment, ichthyosiform erythroderma with hyperkeratotic plaques, palmoplantar keratoderma, alopecia of the scalp and eyelashes, and a thick vernix caseosa-like covering of the scalp. On histological analysis, features characteristic of KID syndrome, such as acanthosis and papillomatosis of the epidermis with basket-weave hyperkeratosis, were seen. The skin symptoms were treated successfully with acitretin 0.5 mg/kg. The boy developed intraventricular and intracerebral haemorrhage, leading to hydrocephalus. His condition was further complicated by septicaemia and meningitis caused by infection with extended-spectrum beta-lactamase-producing Klebsiella pneumoniae. Severe respiratory failure followed, and the child died at 46 weeks of gestational age (13 weeks postnatally). Sequencing of the GJB2 gene showed that the child was heterozygous for a novel nucleotide change, c.263C>T, in exon 2, leading to a substitution of alanine for valine at position 88 (p.Ala88Val). This study has identified a new heterozygous de novo mutation in the Cx26 gene (c.263C>T; p.Ala88Val) leading to KID syndrome.

Autosomal dominant inheritance in a large family with focal facial dermal dysplasia (Brauer–Setleis syndrome)

Focal facial dermal dysplasia (FFDD) (OMIM 227260) is a rare ectodermal disorder characterized by congenital bitemporal scar-like depressions resembling forceps marks and variable additional facial manifestations. No gene defects or gene loci for FFDD are known to date. We report on a large multi-generational German family with typical characteristics of FFDD and provide a detailed clinical description of four affected individuals. They had large bitemporal discolored dermal depressions, sparse lateral eyebrows, abnormal eyelashes, and dysplastic and low-set ears. Three of the four affected individuals had congenital horizontal nystagmus, which had hitherto only been reported in a single patient with FFDD. In contrast to previous assumptions about an autosomal recessive etiology of this disorder, this family provides further evidence that FFDD is inherited in an autosomal dominant mode. Although this family is not large enough to yield significant results in linkage analysis, it may, in combination with other families, contribute to the identification of a gene locus for this intriguing ectodermal disorder.

Oral health in Autoimmune Polyendocrinopathy Candidiasis Ectodermal Dystrophy (APECED)

APECED (Autoimmune Polyendocrinopathy Candidiasis Ectodermal Dystrophy) is a rare autosomal recessive disease characterised primarily by sequential immune-mediated destruction of endocrine tissues, chronic oral or mucocutaneous candidiasis and ectodermal disorders, including hypoplasia of dental enamel. This was to investigate the oral health and presence of enamel defects in a cohort of patients with APECED. 16 patients with APECED (mean age of 13.9 years) were matched for age and gender with healthy controls. A comprehensive medical, dental and drug history was recorded, followed by a clinical assessment of oral health which was determined by assessing periodontal treatment needs, prevalence of dental caries, erosion, fluorosis and enamel defects. The estimated time of the development of the enamel defects and the contemporaneous medical diagnosis were recorded. Oral health of patients with APECED was poor compared with controls, with a higher prevalence of periodontal disease, caries and erosion. There was a significantly (P < 0.05) higher prevalence of enamel defects in the study group. The enamel defects were mostly hypoplastic in the form of pits, missing enamel and grooves. The enamel defects occurred in a chronological pattern. There was a strong association between the estimated time of defective enamel formation and a history of hypoparathyroidism. Gastrointestinal dysfunction and a history of chronic mucocutaneous candidiasis were also associated with the presence of enamel defects. The oral health of individuals with APECED was poor compared with controls with a higher prevalence of periodontal disease, caries, erosion and enamel defects. The enamel defects in the study population occurred in a chronological pattern and some were associated with a history of systemic disease during the period of tooth development.

A Report of GJB2 (N14K) Connexin 26 Mutation in Two Patients—A New Subtype of KID Syndrome?

Keratitis-ichthyosis-deafness syndrome is a rare congenital ectodermal disorder, characterized by presence of skin lesions, neurosensory hearing loss, and vascularizing keratitis. Several autosomal dominant mutations in the Connexin 26 gene (GJB2) have been discovered as a cause of this syndrome. We report two patients who presented with a combination of clinical features of keratitis-ichthyosis-deafness syndrome (e.g., congenital bilateral neurosensory hearing loss and erythrokeratoderma), however, lacking other characteristics typical of this condition. In addition, they both demonstrated striking mucocutaneous findings (e.g., chronic lip fissuring, gingival hyperemia), resulting in diagnostic difficulties. In both patients, a GJB2 mutation (N14K) was identified, which shares the same gene with classic Keratitis-ichthyosis-deafness syndrome but has never been described in patients with this condition. We propose that the findings observed in our patients are a distinct subtype of Keratitis-ichthyosis-deafness syndrome, thus expanding the spectrum of connexin-associated keratodermias.

Trichothiodystrophy‐like Hair Abnormalities in a Child with Keratitis Ichthyosis Deafness Syndrome

Keratitis ichthyosis deafness syndrome is a rare congenital ectodermal disorder. It appears to be genetically heterogeneous and may be caused by mutations in the connexin 26 (Cx26) gene (GJB2) or in the connexin 30 gene. It is characterized by the association of ichthyosis-like skin lesions, hearing loss, and vascularizing keratitis. We report the clinical and molecular findings in a 5-year-old girl with keratitis ichthyosis deafness syndrome. DNA sequencing in our patient revealed a p.Ser17Phe mutation in GJB2. Besides the typical clinical features of keratitis ichthyosis deafness syndrome, a peculiar intriguing finding not previously described in the literature in this condition was that polarizing light microscopy of the scalp hair in our patient revealed striking bright and dark bands as seen in trichothiodystrophy. Amino acid analysis of the hair sample also disclosed a reduced cysteine index. We emphasize that it would be of great benefit to examine hair shafts in other patients with keratitis ichthyosis deafness syndrome for trichothiodystrophy-like abnormalities.

Ocular Manifestations and Histologic Characteristics of Keratitis-Ichthyosis-Deafness (KID) Syndrome

Purpose: Keratitis-ichthyosis-deafness (KID) syndrome is a congenital ectodermal disorder presenting the triad of vascularizing keratitis, erythrokeratoderma, and sensorineural deafness. Ocular manifestations such as hyperkeratinization of the eyelids, loss of eyelashes, keratoconjunctivitis sicca, corneal erosions, ulceration, neovascularization, and scarring opacity may be absent or mild, but if present and severe, they can lead to major visual loss. We report a patient with KID syndrome with severe ocular manifestations and the histologic characteristics of a corneal lesion. Case summary: A 5-year-old boy was referred to the Ophthalmology Department for bilateral hyperkeratinization of eyelids, bare eyelashes, and corneal opacity. He showed hyperkeratotic skin lesions and sensorineural hearing loss. Molecular analysis showed a mutation in the GJB2 gene and confirmed the diagnosis of KID syndrome. Initial conservative treatment did not preserve ocular surface integrity, and instead it was maintained by surgical procedures including superficial lamellar keratectomy with amniotic membrane transplantation. The histologic characteristics of corneal lesions are abnormal epithelial differentiation, absence of connexin 26 expression, and partial destruction of the basement membrane.

Woolly Hair and Palmoplantar Hyperkeratosis May Present with Hypertrophic Cardiomyopathy

Woolly hair and palmoplantar hyperkeratosis is an infrequent autosomal recessive ectodermal disorder that may be associated with arrhythmogenic right ventricular dysplasia (Naxos disease) or dilated cardiomyopathy. We report the sporadic occurrence of the aforementioned skin-hair anomalies in a patient with physical findings compatible with Noonan's syndrome and hypertrophic cardiomyopathy-an association heretofore not described.

Ichthyosis Follicularis with Alopecia and Photophobia in a Girl with Cataract: Histological and Electron Microscopy Findings

A rare congenital ectodermal disorder characterized by ichthyosis follicularis, alopecia and photophobia has been designated the acronym IFAP. An X-linked recessive mode of inheritance was initially proposed but a few recent reports in girls suggested genetic heterogeneity of this syndrome. We herein describe a 3-year-old girl with clinical and histological features typical of IFAP. In addition to the already known features of the syndrome the patient also developed bilateral cataract. Electron microscopy examination of the skin showed partial disruption of the intercellular bridges, spongiotic changes and decrease in the number and size of desmosomes supporting the notion that IFAP may be a cell-to-cell adhesion disorder.

Genodermatoses 2003-2004

Many genodermatoses have been linked in recent years to their respective genes. The underlying biology and integrative nature of these genes with other genes and organ systems is beginning to be understood. This paper reviews recent advances in neurocutaneous disorders, ectodermal dysplasias, and the phenomenon of revertant gene mosaicism. In neurofibromatosis type 1, molecular assays are being developed to distinguish malignant from benign and premalignant lesions. Clinical mutation analysis for the NF1 gene has been problematic; a sensitive new assay using automated comparative sequence analysis may be helpful. Revision of clinical care guidelines is ongoing. New data for the prospective management of optic pathway gliomas is reviewed. The two genes that underlie tuberous sclerosis complex, tuberin and hamartin, lie at the center of an important signal transduction pathway with significant implications for pharmacologic treatment. Issues in genetic counseling for this highly variable disease are updated. Extensive progress has been made in understanding the basis of several forms of ectodermal dysplasia. Disorders caused by mutations in p63 and the connexin and NF-kappaB gene families will be reviewed. Finally, phenotypic in vivo amelioration of genodermatoses via revertant gene mosaicism will be discussed as a possible mechanism to be exploited in directed therapeutic approaches. This paper reviews recent developments in the molecular and biologic bases of neurofibromatosis type 1, tuberous sclerosis, and ectodermal disorders related to p63 and the connexin and NF-kappaB gene families. The concept of revertant gene mosaicism is also discussed as a potential model for gene therapy.

The genetic background of autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy and its autoimmune disease components.

Autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED) is a rare autosomal recessive disorder characterized by an immune-mediated destruction of endocrine tissues, chronic candidiasis, and additional ectodermal disorders. In contrast to many other autoimmune diseases, APECED is associated with mutations of a single gene, designated autoimmune regulator (AIRE). To date, 45 different mutations of the AIRE gene have been identified and are distributed throughout the entire coding region. Several of the AIRE mutations predict the transcription and translation of a truncated protein, which may be nonfunctional. In contrast to the genetic background of APECED, in all of the autoimmune conditions typically associated with APECED the conclusive role of a single genetic locus capable of providing insight into the etiology of the disease has not been identified. Here we provide an overview of the current clinical and genetic features of APECED in comparison to the genetic background of the frequently associated disease components of APECED.

The Autoimmune Regulator (AIRE) Is a DNA-binding Protein

The autoimmune regulator (AIRE) protein is a putative transcription regulator with two plant homeodomain-type zinc fingers, a putative DNA-binding domain (SAND), and four nuclear receptor binding LXXLL motifs. We have shown here that in vitro, recombinant AIRE can form homodimers and homotetramers that were also detected in thymic protein extracts. Recombinant AIRE also oligomerizes spontaneously upon phosphorylation by cAMP dependent protein kinase A or protein kinase C. Similarly, thymic AIRE protein is phosphorylated at the tyrosine and serine/threonine residues. AIRE dimers and tetramers, but not the monomers, can bind to G-doublets with the ATTGGTTA motif and the TTATTA-box. Competition assays revealed that sequences with one TTATTA motif and two tandem repeats of ATTGGTTA had the highest binding affinity. These findings demonstrate that AIRE is an important DNA binding molecule involved in immune regulation.

Whiskers amiss, a new vibrissae and hair mutation near the Krt1 cluster on mouse chromosome 11.

Whiskers amiss (wam) is a new spontaneous recessive mutation in the SELH/Bc strain of mice that causes a phenotype of askew, sometimes kinked or curled, breakable whiskers and disheveled-appearing body hair, apparently owing to disoriented guard hairs. Heterozygotes on three genetic backgrounds are indistinguishable from normal. Using informative SSLPs in the F2 generation after crosses to two normal strains, we have mapped wam to the region of the type I keratin cluster on Chromosome (Chr) 11, within an approximately 6-cM segment according to the current Mouse Genome Database (MGD) map position of flanking SSLPs. Although several other hair mutations also map to the Krt1 region (Re, Rim3, Bdai, Bsk), none has a hair and whisker phenotype similar to that of wam, and, because all are transmitted as dominants, interpretable complementation tests could not be done. Scabbing and tissue loss occur on the rims of the pinnae and tail tip in some aging wam homozygotes, suggesting that wam may be an animal model of a genetic ectodermal disorder. The SELH/Bc strain background appears to have an unusually high rate of spontaneous mutation; wam is the sixth mutation to be described.

Ornithine decarboxylase transgenic mice as a model for human atrichia with papular lesions.

The hair follicle is characterized by cyclic transformations from active growth and hair fiber production through regression into a resting phase. The growth phase, known as anagen, is associated with rapid rates of cell turnover, and variations in the rate of DNA synthesis in mouse skin throughout the hair cycle are accompanied by changes in the activity of ornithine decarboxylase (ODC), a key enzyme in the synthesis of polyamines, which are actively involved in regulation of normal cell division, differentiation, and growth. Previously, a transgenic mouse was created that overexpressed ODC in the skin using a K6 promoter. The first hair cycle in neonatal transgenic mice appeared to be normal, but by the third week of postnatal life transgenic pups begin to progressively lose hair. The lower portion of the hair follicle was progressively replaced with enlarging cystic structures located in the deep dermis, and the transgenic mice exhibited excessive growth of skin mass resulting in pronounced wrinkling and folding. Interestingly, these findings bore striking resemblance to the rhino mouse phenotype and to human patients with papular atrichia, a rare congenital ectodermal disorder characterized by progressive and irreversible hair loss in early childhood. The similarities in phenotype between transgenic mice and human atrichia with papular lesions suggest that ODC transgenics may represent a useful model for studying this disorder. It appears that ODC plays a functionally important, yet still obscure role in a complex metabolic pathway that is critical in hair follicle function not only in mice, but in humans as well.

The incidence and pathophysiology of atopic dermatitis

Aim To review our present knowledge about atopic dermatitis and try to formulate a working hypothesis about disease mechanisms.Subject Atopic dermatitis and disease mechanisms.Methods Literature review.Results Atopic dermatitis is a skin disorder which develops within the first years of life, is active for a number of years and then resolves in most affected individuals. Although no single disease-associated gene locus has been found, observations among monozygous and dizygous twins suggest that atopic dermatitis is first and foremost a genetically determined disease. Atopic dermatitis is associated with an abnormal dryness of the skin due to a deficient skin barrier function. Although it seems to be a genetically determined ectodermal disorder, it includes immune deviations such as T lymphocyte accumulation in the skin leading to chronic relapsing eczema. In some patients increased serum IgE is found and type I allergies are common. However, the immune deviations are not always associated with type I or type IV allergies. If allergies were of primary importance for disease development, it is hard to explain why the eczema disappears despite the presence of environmental allergens. Some kind of “maturation step” is likely involved in the down-regulation of eczema.Many epidemiological studies indicate that the incidence of atopic dermatitis has doubled or tripled over the last two decades. This is difficult to explain, if the disease is mostly genetically determined. However, it could be explained, if atopic dermatitis is considered a dysmaturation of the immune system and that the expression of a genetically determined dysmaturation can be influenced by the age of the mother — comparable to what is found concerning the risk of developing Down's syndrome.Conclusion This review summarizes known facts and puts foreward a working hypothesis that atopic dermatitis may be a genetically determined dysmaturation of the T lymphocyte system. T lymphocytes mature primarily in the thymus via positive and negative selection processes. This includes contact between pre-T cells and the thymic epithelium, which is derived from the ectoderm. We hypothesize that the maturation of the T cell immune system is disturbed, resulting in a faulty selection of T lymphocytes in the thymus. “Dys”-matured T cells leave the thymus to continue growth in the skin. The cells are eventually eradicated by immune surveillance in the patient. Because of the increased proliferation of “dysmature” T cells, a cytokine imbalance occurs, and in some patients this leads to the development of type I allergies.

Ectodermal Disorders in Chronic Hypoparathyroidism

CHANGES in structures of ectodermal origin in chronic hypoparathyroidism have been described repeatedly. In most cases these disorders were noted as incidental findings of secondary importance. The case which is to be reported presented as a striking part of the clinical picture, skin, hair and nail abnormalities. In addition there were other unusual features. CASE REPORT Mrs. M. M., a 50-year old Slovakian woman, was admitted on Dr. C. L. Brown's service on May 18,1942, complaining of numbness and stiffness of the hands and feet and a recurrent skin disease. She had been in excellent health until 20 years ago, when at the age of 30 she developed difficulty in breathing. Thyroidectomy was advised and done. Following the operation she was relieved of dyspnea, but 5 days later there occurred numbness of the hands and feet accompanied by stiffness in these extremities. These symptoms were relieved by the administration of a calcium salt. On discharge from the hospital she was advised to take one drachm of ca...