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In this report we present the unique combination of hypohidrotic ectodermal dysplasia, primary hypothyroidism, and agenesis of the corpus callosum in a two year old, severely mentally retarded boy.
X linked hypohidrotic ectodermal dysplasia was studied in the dentition of both affected males and carrier females. Hypodontia was more severe in males than females and there were differences in the pattern of tooth absence between the sexes. Abnormal crown form, with the maximum diameter of the teeth being apically displaced, was noted particularly in the anterior teeth. Taurodontism was commonly seen radiographically.
A brother and sister from the island of Rodrigues had mental retardation, blindness owing to severe ocular malformations, short stature, dysmorphic facial features, hypotrichosis, and dental abnormalities. It is likely that they have a hitherto unrecognised autosomal recessive ectodermal dysplasia syndrome.
Two brothers are documented with an ectodermal dysplasia primarily involving the teeth and hair. Both have developed cerebellar ataxia in the early teens.
Hay and Wells in 1976 reported seven patients from four families who had an inherited condition of which the main features were ankyloblepharon, ectodermal defects, and cleft lip and palate. The inheritance pattern was determined to be autosomal dominant. This condition is known as AEC syndrome or Hay-Wells syndrome. We report a family with two sibs showing some of these features and congenital adhesions between the upper and lower jaws (alveolar synechiae). There seems to be a recessive pattern of inheritance as neither of the parents has any features of the syndrome. This could be described as a recessive form of Hay-Wells syndrome with additional features or be named as a new syndrome.
Hypohidrotic ectodermal dysplasia (EDA) has been localised to the q12-q13.1 region of the X chromosome by both physical and genetic mapping methods. Although linkage analysis using closely linked flanking markers can clarify the carrier status for many females at risk for the disorder, knowledge of the origin of the mutation in instances of possible de novo mutation is critical for accurate genetic counselling of families. Two methods have been used to confirm de novo mutation in families with EDA and to trace their origin. Direct detection of three de novo molecular deletions, one arising during oogenesis and the other two during spermatogenesis, was achieved by Southern analyses using cosmids isolated from the EDA region as probes. Seven de novo mutations arising during spermatogenesis, and two possible de novo mutations during oogenesis, were identified by an analysis of the cosegregation of the disorder with polymorphic markers closely linked to and flanking the EDA locus. The confirmation and analysis of the origin of the 10 de novo mutations greatly assisted genetic counselling in these families. The apparent 3.5:1 excess of male to female origin of mutation in families studied with unidentified types of mutation is similar to other studies of X linked disorders, and suggests that the majority of these mutations may involve single base pair substitutions.
This paper describes odontomicronychial dysplasia, a pure ectodermal dysplasia of the 2-3 subgroup of group A. It is characterised by precocious eruption and shedding of deciduous dentition, precocious eruption of secondary dentition with short, rhomboid roots, and short, thin, slow growing nails. This condition probably results from an autosomal recessive gene.
Indirect molecular diagnosis of X linked hypohidrotic ectodermal dysplasia (XLHED), a congenital disorder of hair, teeth, and eccrine sweat glands, has been possible by linkage analysis. Direct mutation detection would enable carrier detection in female relatives of sporadic cases, as well as help distinguish XLHED from the rarer, clinically indistinguishable, autosomal recessive disorder ARHED. Recently, a candidate gene for XLHED has been identified. Genomic DNA from 162 affected males and 21 females, who were either obligate carriers or had manifestations of the disorder, were screened by SSCP analysis. A subset of the patients had been previously screened for large genomic deletions and had limited screening of a single exon by SSCP analysis. The two known exons were amplified using flanking primers. Approximately 7% of patients, all males, had putative mutations identified within exon 1, but no variants were found within exon 2. Ten different putative mutations and four probable polymorphisms were identified. Both of the known exons were sequenced in 10 patients who had no detectable SSCP changes, but no additional mutations were found. No correlation between phenotype and genotype was evident between either affected subjects or subjects with or without detectable mutations. The results of the study indicate that only a small minority of affected males can be diagnosed by direct mutation analysis, and that the remainder of the patients are likely to have mutations in as yet unidentified exons of the EDA gene. Linkage analysis, in informative situations, therefore remains the only practical diagnostic option available.
X-linked hypohidrotic ectodermal dysplasia (XLHED; MIM 305100) is characterized by the absence or hypoplasia of hair, teeth, and sweat glands. The ED1 gene was identified as a responsive gene for XLHED. The patients were 2 Japanese brothers. Both had the same mutation in exon 1 of the ED1 gene, i.e. C deletion at nucleotide 49, which induced a frameshift starting from amino acid 17 and made a stop codon at amino acid 56, encoding the transmembrane site. The mutation caused the extracellular domain of ectodysplasin A to be completely absent. Their mother had a heterozygous allele; she congenitally lacked 1 tooth, and incisors appeared conical in form.
A girl is reported with a hitherto apparently undescribed ectodermal dysplasia syndrome. The main findings include: alopecia, onychodysplasia, hypohidrosis, sensorineural deafness, skin with a tan color and hyperkeratosis (involving also plams and soles), unusual facies (with slight auricle and nose abnormalities), pectus excavatum, severe hyperopia, EEG abnormalities, and retarded bone age. The patient also presents mongoloid palpebral slanting, narrow palpebral fissures, bilateral esotropia, photophobia and dermatoglyphics with extensive ridge dissociation. The etiology is unknown but presumed to be genetic, possibly due to the homozygous state of an autosomal recessive mutation.
Activin possesses mesoderm-inducing activity, erythroid-differentiating activity, and follicle-stimulating hormone-releasing activity. The chemical structures of the activin molecule are formed by a combination of two beta-subunit peptides of inhibin. Inhibin is a dimer consisting of an alpha and beta subunit. To examine the mesoderm-inducing activity of these substances, we tested several configurations including: (1) two types of alpha-subunit peptide; (2) two types of inhibin A and B dimer; (3) beta A-subunit peptide monomer; (4) three types of activins A, AB and B, and (5) follistatin (activin-binding protein) by the animal cap assay using Xenopus laevis ectoderm, and by the erythroid-differentiating factor (EDF) test. Activins, which are composed of dimeric inhibin beta A- or beta B-subunit peptides, had the highest mesoderm-inducing and EDF activities. The monomeric beta A-subunit peptide exhibited mesoderm-inducing and EDF activities that were much lower than activin A. The inhibitory effect of follistatin on mesodermal induction by the beta A-subunit peptide was also lower than that of activin. Both inhibins A and B had very weak mesoderm-inducing activity and no EDF activity. The two types of inhibin alpha-subunit monomer had little mesoderm-inducing activity and no EDF activity. The mesoderm induction caused by activin A was not suppressed by the addition of the alpha-subunit monomer and inhibin. The mesoderm-inducing activity in relation to the chemical structures of the monomeric and/or dimeric inhibin alpha and beta A subunits is discussed.
Several clinical syndromes are characterized by ectodermal dysplasia (ED) in association with clefting of the lip and/or palate. In these syndromes, alopecia is primarily due to abnormalities of the hair shaft associated with increased hair fragility. Scalp dermatitis is yet another peculiar finding, primarily seen in the ankyloblepharon-ED-clefting (AEC) syndrome. We report on a 16-year-old patient with ectrodactyly-ED-clefting (EEC) syndrome, who exhibited a scarring alopecia due to deep folliculitis. On scanning electron microscopy, irregular torsion and longitudinal grooving of the hair shaft (pili torti et canaliculi) were observed. Quantitative determinations of the elastic and viscous parameters of hair demonstrated a normal viscosity but a significantly reduced hair elasticity, indicating either an abnormal composition or a disordered arrangement of microfibrils within the apparently normal keratin matrix. In contrast to the erosive scalp dermatitis of early onset in the AEC syndrome, alopecia in this case of EEC syndrome demonstrated follicular scarring with onset during puberty. We question a possible role of the anatomical hair abnormality in the pathogenesis of chronic deep folliculitis in this and clinically related syndromes.
An isolated affected 19-year-old male with hypohidrotic ectodermal dysplasia (HED) had rare features of the syndrome such as recurrent otitis and multiple sebaceous gland papules of the face. Sebaceous gland hypertrophy is puzzling in the context of HED.
Hidrotic ectodermal dysplasia (HED) was observed in a 49-year-old Japanese man. His clinical signs included alopecia, dystrophic nails and palmoplantar keratoderma, but his teeth, facial appearance and sweating were normal. In his family, 9 members in 5 generations were affected, suggesting that the disorder has an autosomal dominant mode of inheritance. Biopsy specimens of the hyperkeratotic lesions of the palm and sole were studied with an electron microscope. The most prominent feature was the increase of the number of desmosomal discs in the thickened stratum corneum, suggesting that hyperkeratosis observed in HED is due to the delayed desquamation of the stratum corneum.
Patients with hypohidrotic ectodermal dysplasia (HED) and Tabby (Ta) mice lack sweat glands and there is compelling evidence that these phenotypes are caused by mutations in the same highly conserved but unidentified X-linked gene. Previous studies showed that exogenous epidermal growth factor (EGF) reversed the Ta phenotype but the EGF status in HED patients has not been studied at all. Studies reported herein investigated the hypothesis that the EGF signaling pathway is involved in HED/Ta. Fibroblasts from HED patients had a two- to eightfold decrease in binding capacity for (125)I-labeled EGF, a decreased expression of the immunoreactive 170-kD EGF receptor (EGFR) protein, and a corresponding reduction in EGFR mRNA. Reduced expression of the EGFR also was observed in Ta fibroblasts and liver membranes. Other aspects of the EGF signaling pathway, including EGF concentration in urine and plasma, were normal in both HED patients and Ta mice. We propose that a decreased expression of the EGFR plays a causal role in the HED/Ta phenotype.
X-linked anhidrotic ectodermal dysplasia with immunodeficiency (XL-EDA-ID) is caused by hypomorphic mutations in the gene encoding NEMO/IKKgamma, the regulatory subunit of the IkappaB kinase (IKK) complex. IKK normally phosphorylates the IkappaB-inhibitors of NF-kappaB at specific serine residues, thereby promoting their ubiquitination and degradation by the proteasome. This allows NF-kappaB complexes to translocate into the nucleus where they activate their target genes. Here, we describe an autosomal-dominant (AD) form of EDA-ID associated with a heterozygous missense mutation at serine 32 of IkappaBalpha. This mutation is gain-of-function, as it enhances the inhibitory capacity of IkappaBalpha by preventing its phosphorylation and degradation, and results in impaired NF-kappaB activation. The developmental, immunologic, and infectious phenotypes associated with hypomorphic NEMO and hypermorphic IKBA mutations largely overlap and include EDA, impaired cellular responses to ligands of TIR (TLR-ligands, IL-1beta, and IL-18), and TNFR (TNF-alpha, LTalpha1/beta2, and CD154) superfamily members and severe bacterial diseases. However, AD-EDA-ID but not XL-EDA-ID is associated with a severe and unique T cell immunodeficiency. Despite a marked blood lymphocytosis, there are no detectable memory T cells in vivo, and naive T cells do not respond to CD3-TCR activation in vitro. Our report highlights both the diversity of genotypes associated with EDA-ID and the diversity of immunologic phenotypes associated with mutations in different components of the NF-kappaB signaling pathway.
We examined the activity of X-linked glucose-6-phosphate dehydrogenase (G6PD) in concepti of the enzyme-deficient mutant and wild-type C3H mice. By using different crosses between the G6PD-deficient homozygous, heterozygous, or wild-type females and hemizygous or wild-type males, we confirmed the inactivation of one of the two X chromosomes in female concepti by a histochemical method. With this technique, a dual (G6PD + or -) cell population could be observed in the tissue sections. We demonstrate that the paternal X chromosome is inactivated in the endoderm of parietal and visceral yolk sac and in the trophoblast, whereas in the embryo and in the yolk sac mesoderm this inactivation is random. Our results confirm biochemical observations showing that only the maternal X chromosome is expressed in all derivatives of trophectoderm and primitive endoderm, whereas derivatives of the primitive ectoderm show random X chromosome expression.
X-linked ectodermal dysplasia and immunodeficiency (XL-EDA-ID) is an X-linked recessive disease caused by a mutation in the nuclear factor-kappaB (NF-kappaB) essential modulator (NEMO). Here we report an XL-EDA-ID patient with atypical features of very few naive-phenotype T cells and defective mitogen-induced proliferation of peripheral blood mononuclear cells (PBMCs). The patient's NEMO defect was diagnosed by flow cytometric analysis of intracellular NEMO staining. Specific cell lineages (monocytes and neutrophils) expressed reduced levels of NEMO, but 2 populations of T, B, and NK cells were detected with normal and reduced expression of NEMO. Genomic analysis revealed that duplication of a 4.4-kb sequence ranging from intron 3 to exon 6 caused the reduced expression of NEMO. Polymorphism analysis showed that the patient's B- and T-cell lines with reduced and normal expression of NEMO had the same X chromosome, indicating that the somatic mosaicism was not due to fetomaternal transfusion but was most likely due to postzygotic reversion. This XLEDA-ID case adds to our understanding of NEMO biology, indicating that NEMO is critical for T-cell development and/or survival in humans as well as in mice.