Gene effect in carriers of anhidrotic ectodermal dysplasia

Human temperature regulation under heat stress in health, disease, and injury

The human body constantly exchanges heat with the environment. Temperature regulation is a homeostatic feedback control system that ensures deep body temperature is maintained within narrow limits despite wide variations in environmental conditions and activity-related elevations in metabolic heat production. Extensive research has been performed to study the physiological regulation of deep body temperature. This review focuses on healthy and disordered human temperature regulation during heat stress. Central to this discussion is the notion that various morphological features, intrinsic factors, diseases, and injuries independently and interactively influence deep body temperature during exercise and/or exposure to hot ambient temperatures. The first sections review fundamental aspects of the human heat stress response, including the biophysical principles governing heat balance and the autonomic control of heat loss thermoeffectors. Next, we discuss the effects of different intrinsic factors (morphology, heat adaptation, biological sex, and age), diseases (neurological, cardiovascular, metabolic, and genetic), and injuries (spinal cord injury, deep burns, and heat stroke), with emphasis on the mechanisms by which these factors enhance or disturb the regulation of deep body temperature during heat stress. We conclude with key unanswered questions in this field of research.

The characterization of hypodontia, hypohidrosis, and hypotrichosis associated with X-linked hypohidrotic ectodermal dysplasia: A systematic review

The objective of this study was to review the published literature on X-linked hypohidrotic ectodermal dysplasia (XLHED) for the prevalence and characteristics of three features of XLHED: hypodontia, hypohidrosis, and hypotrichosis. A systematic search of English-language articles was conducted in May 2019 to identify publications with information on any of the three features of XLHED. We excluded studies with five or fewer participants, that did not specify X-linked inheritance or an EDA mutation, and discussed only management of features. The weighted means for total missing teeth, location of missing teeth, prevalence of reduced and absent sweating ability, and sparse or absent hair were analyzed across all studies. Additional findings for hypodontia, hypohidrosis, and hypotrichosis were summarized qualitatively. Twenty publications (18 studies) were accepted. Reported findings for males tended to be more informative than for carrier females. The weighted mean for missing teeth for affected males was 22.4 (range: 10-28) and carrier females was 3.4 (range: 0-22). The most common conserved teeth for males were the canines. The most common missing teeth for females were the maxillary lateral incisors. The weighted mean prevalence of reduced or absent sweating ability was 95.7% for males and 71.6% for females. The weighted mean prevalence for hypotrichosis was 88.1% for males and 61.6% for females. This systematic review provides insight into the prevalence, characteristics, and variability of the three classic features of XLHED. These findings provide detailed natural history information for families with XLHED as well as key characteristics that can aid in diagnosis.

A de Novo EDA-Variant in a Litter of Shorthaired Standard Dachshunds with X-Linked Hypohidrotic Ectodermal Dysplasia

In this study, we present a detailed phenotype description and genetic elucidation of the first case of X-linked hypohidrotic ectodermal dysplasia in the shorthaired standard Dachshund. This condition is characterized by partial congenital hypotrichosis, missing and malformed teeth and a lack of eccrine sweat glands. Clinical signs including dental radiographs and histopathological findings were consistent with ectodermal dysplasia. Pedigree analysis supported an X-recessive mode of inheritance. Whole-genome sequencing of one affected puppy and his dam identified a 1-basepair deletion within the ectodysplasin-A (EDA) gene (CM000039.3:g.54509504delT, c.458delT). Sanger sequencing of further family members confirmed the EDA:c.458delT-variant. Validation in all available family members, 37 unrelated shorthaired standard Dachshunds, 128 further Dachshunds from all other coat and size varieties and samples from 34 dog breeds revealed the EDA:c.458delT-variant to be private for this family. Two heterozygous females showed very mild congenital hypotrichosis but normal dentition. Since the dam is demonstrably the only heterozygous animal in the ancestry of the affected animals, we assume that the EDA:c.458delT-variant arose in the germline of the granddam or in an early embryonic stage of the dam. In conclusion, we detected a very recent de-novo EDA mutation causing X-linked hypohidrotic ectodermal dysplasia in the shorthaired standard Dachshund.

Perinatal Autopsy Findings in a Case of De Novo Hypohidrotic Ectodermal Dysplasia

Ectodermal dysplasia are group of inherited disorders involving the developmental defects of ectodermal structures like hair, teeth, nails, sweat glands, and others. X-linked recessive inheritance is most common. Here we describe perinatal autopsy findings in a case of de novo ectodermal dysplasia in a female fetus. To the best of our knowledge, this is the first fetal autopsy description in a case of ectodermal dysplasia.

Repeated salicylic acid peels for the treatment of hyperplastic sebaceous glands in hypohidrotic ectodermal dysplasia

Hypohidrotic ectodermal dysplasia (Christ-Siemens-Touraine syndrome) is the most common type of ectodermal dysplasia. Hypertrophic sebaceous glands (HSGs) are rarely present but they cause an aesthetic problem. We report a case of a patient suffering from hypohidrotic ectodermal dysplasia, treated with salicylic acid peels for the hyperplastic sebaceous glands.

Karyotyping, dermatoglyphic, and sweat pore analysis of five families affected with ectodermal dysplasia

Background:

Hereditary ectodermal dysplasia is a genetic recessive trait characterized by hypohydrosis, hypotrichosis, and hypodontia. The affected individual show characteristic physiognomy like protruded forehead, depressed nasal bridge, periorbital wrinkling, protruded lips, etc. There is marked decrease in sweat and salivary secretion. Due to skin involvement palm and sole ridge patterns are disrupted.

Aim:

In this study an attempt has been made to classify the affected members according to the degree of penetrance by pedigree analysis and also study karyotyping for cytogenetics, dermatoglyphic analysis for the various ridge patterns and variations in the number of sweat glands by sweat pore analysis in affected individuals.

Materials and Methods:

A total of five families who were affected with ectodermal dysplasia were considered. Pedigree analysis was drawn up to three generation by obtaining history. Dermatoglyphics and sweat pore analysis was done by obtaining palm and finger print impression using stamp pad ink. Karyotyping was done by collecting 3–5 ml peripheral blood. Karyotyping was prepared using lymphocyte culture. Chromosomes were examined at 20 spreads selected randomly under ×100 magnification. Results were analyzed by calculating mean values and percentage was obtained.

Results:

Karyotyping did not show any abnormalities, dermatoglyphic analysis and sweat pore counts showed marked variations when compared with normal. Moreover, pedigree analysis confirmed the status of the disease as that of the recessive trait.

Conclusion:

Large number of affected patients needs to be evaluated for dermatoglypic analysis. Genetic aspect of the disease needs to be looked into the molecular level in an attempt to locate the gene locus responsible for ectodermal dysplasia and its manifestation.

Ectodermal dysplasias: a clinical and molecular review

The ectodermal dysplasias are a large group of hereditary disorders characterized by alterations of structures of ectodermal origin. Although some syndromes can have specific features, many of them share common clinical characteristics. Two main groups of ectodermal dysplasias can be distinguished. One group is characterized by aplasia or hypoplasia of ectodermal tissues, which fail to develop and differentiate because of a lack of reciprocal signaling between ectoderm and mesoderm, the other has palmoplantar keratoderma as its most striking feature, with additional manifestations when other highly specialized epithelia are also involved. In recent decades, the genes responsible for at least 30 different types of ectodermal dysplasia have been identified, throwing light on the pathogenic mechanisms involved and their correlation with clinical findings.

Orofacial features of hypohidrotic ectodermal dysplasia

Hypohidrotic ectodermal dysplasia (HED) is a type of genodermatosis characterized by the abnormal development of sweat glands, teeth, and hair. The most prevalent form of HED is X-linked hypohidrotic ectodermal dysplasia (XLHED), which is associated with mutations in the EDA gene. The aim of this case report was to describe a family with XLHED with emphasis on differences in orofacial features between members. Family members were systematically evaluated to characterize the pattern of inheritance and clinical features. Dental examination included evaluation of agenesis and abnormal teeth structure. The pedigree of the last seven generations of the family was constructed. Clinical examination and medical history revealed five males affected by HED and nine female as heterozygous carriers. The males exhibited the classic phenotype of XLHED, with dental abnormalities, hypohydrosis, and craniofacial dysmorphologies. The heterozygous carriers of the X-linked gene defect principally exhibited dental agenesis of the lateral maxillary incisors. Careful clinical examination, including dental evaluation, is an important way to detect heterozygous carriers of X-linked HED. Heterozygous parents of patients with HED may also show some features of the disorder. The identification of female carriers results in genetic counseling being offered to affected families, as well as providing adequate treatment as necessary and long-term follow-up of these patients.

Human genes for dental anomalies

The development of the tooth at gene level is beginning to be understood. This paper reviews current knowledge and the advances in research on human genes whose defect leads to dental anomalies. Amelogenesis imperfecta (AI) is a diverse group of hereditary disorders characterized by a variety of developmental enamel defects including hypoplasia and hypomineralization, some of which have been revealed to be associated with defective amelogenin genes. The human amelogenin genes on X and Y chromosomes have been cloned and investigated extensively. Although autosomally inherited forms of AI are more common than the X-linked forms, most studies on the genes causing AI have been performed on the genes of X-linked forms. Recently, the gene for the human tuftelin protein (an enamelin) has been cloned as a candidate gene for the autosomal forms of AI with another gene on chromosome 4 involved in some families. Dentinogenesis imperfecta (DI) may be associated with osteogenesis imperfecta (OI), which is an autosomal dominant bone disease. Most patients with OI have mutations in either the COLIA1 or COLIA2 genes, which encode the alpha 1(I) or alpha 2(I) subunits of type I collagen, the major organic component of bone and dentin. Gene defects causing isolated DI have not been identified. Recently, it was demonstrated that a missense mutation of MSXI, a human homeobox gene, causes autosomal dominant agenesis of second premolars and third molars. Data indicating an important function for MSXI, the mouse counterpart of the human MSXI gene, in mouse tooth development have been accumulating since 1991. Knockout mice lacking this gene exhibited multiple craniofacial anomalies including complete tooth agenesis. X-linked anhidrotic ectodermal dysplasia (EDA), characterized by abnormal hair, teeth, and sweat glands, was demonstrated to be caused by a mutation in a novel transmembrane protein gene that is expressed in epithelial cells and in other adult and fetal tissues. The predicted EDA protein may belong to a novel class of proteins with a role in epithelial-mesenchymal signaling. Several mutations have been reported in genes causing hypophosphatasia, which is characterized by defective mineralization of the skeletal and dental structures.

X-linked anhidrotic (hypohidrotic) ectodermal dysplasia is caused by mutation in a novel transmembrane protein

Ectodermal dysplasias comprise over 150 syndromes of unknown pathogenesis. X-linked anhidrotic ectodermal dysplasia (EDA) is characterized by abnormal hair, teeth and sweat glands. We now describe the positional cloning of the gene mutated in EDA. Two exons, separated by a 200-kilobase intron, encode a predicted 135-residue transmembrane protein. The gene is disrupted in six patients with X;autosome translocations or submicroscopic deletions; nine patients had point mutations. The gene is expressed in keratinocytes, hair follicles, and sweat glands, and in other adult and fetal tissues. The predicted EDA protein may belong to a novel class with a role in epithelial-mesenchymal signalling.

Sweat testing to identify female carriers of X linked hypohidrotic ectodermal dysplasia

X linked hypohidrotic ectodermal dysplasia (XHED) affects many epithelial functions, including sweat gland formation. Female carriers who manifest XHED may have defective dentition or a patchy distribution of sweating or both, as determined by starch and iodine sweat testing. Such sweat testing can be useful in assigning carrier status to at risk females in XHED families, and in obtaining an accurate diagnosis for isolated females who present with features of ectodermal dysplasia. The advantages of diagnosing female carriers of XHED include the optimisation of neonatal and paediatric care for affected male infants, who may be at substantial risk of death in infancy.

Identification of functioning sweat pores and visualization of skin temperature patterns in X-linked hypohidrotic ectodermal dysplasia by whole body thermography

In this preliminary study, non-invasive infrared thermography has been used to visualize individual sweat pores and whole body skin temperature patterns in subjects with X-linked hypohidrotic ectodermal dysplasia (XHED) and normal controls. The findings in eight obligate heterozygotes and four affected males were compared to six normal female controls and to six non-manifesting females at risk for carrier status. Sweat secretion from individual pores in circumscribed areas was imaged using a high spatial resolution SPRITE infrared detector system working in the 8-14 microns band. In seven out of eight obligate heterozygotes, skin areas devoid of active sweat glands were found on the face, the hands or the trunk. Tear front movement over the cornea was also visualized and abnormal patterns were identified in obligate heterozygotes. Whole body skin temperature patterns, obtained with an Agema 780 Medical Thermovision system, identified abnormal skin temperature distributions, including characteristic aberrant "cascade" back patterns, in obligate carriers. Two out of six "at risk" females had skin temperature patterns comparable with obligate heterozygotes and we have tentatively concluded that they are carriers. Thermal imaging may be used for the examination of "at risk" non-manifesting females in families with a single affected male. The results of this study suggest that the random X-inactivation in females with XHED, as well as producing relatively large skin areas with sweat pore aplasia, is also associated with abnormal temperature patterns that are consistent with altered peripheral vascular perfusion.

Facial morphometrics in the identification of gene carriers of X-linked hypohidrotic ectodermal dysplasia

Roentgenographic measurements and morphometric analysis were employed in the investigation of contrasting patterns of craniofacial variation between normal individuals and those affected by X-linked hypohidrotic ectodermal dysplasia (HED). The research objective was to identify and describe the facial characteristics of heterozygous gene carriers who show minor expression of the disorder. In this study of 13 HED families with 16 affected males, 12 carriers, and 12 normal individuals, affected individuals had at least 3 of the following 4 clinical signs and symptoms: a) hypodontia, b) hypohidrosis, c) hypotrichosis, and d) clinically distinct facial physiognomy. By contrast, the gene carriers manifested only one or 2 or none of the 4 clinical manifestations. In a preliminary comparison of gene carriers vs. normal individuals, we have generated 2 discriminant functions (each based on 3 facial measurements taken either from the lateral or frontal cephalograms). These 2 functions correctly diagnose 100% of the gene carriers and normal HED relatives. Facial anomalies characteristic of the gene carriers were 1) abnormally narrow and short maxillary width and palatal depth dimensions; 2) very small and retrusive malar and maxillary regions; 3) markedly reduced lower facial depth, height and width dimensions; 4) small head height, prominent forehead, and high-set orbits; 5) a generalized, symmetric reduction of the whole craniofacial complex.

Improved definition of carrier status in X-linked hypohidrotic ectodermal dysplasia by use of restriction fragment length polymorphism-based linkage analysis

The detection of carriers of the X-linked disorder hypohidrotic ectodermal dysplasia is problematic because of random X-inactivation; the diagnosis was previously based on the observation of subtle defects in ectodermal structures in at-risk females. Linkage studies have recently mapped hypohidrotic ectodermal dysplasia to the region Xq11-q21.1. We assessed the improvement in carrier detection by the method of linkage analysis, in which restriction fragment length polymorphisms were used as markers, in 72 at-risk female members of 29 families. Carriers analyses were based on pedigree information, dental examination of at-risk females (phenotype), and DNA analyses at seven linked marker loci. Linkage analysis based on restriction fragment length polymorphisms significantly improved risk estimates over those based on phenotype and pedigree alone. When all available information was combined, 85% (61/72) of the at-risk females had final risks of less than 5% or greater than 95%, and 68% (49/72) had risks less than 1% or greater than 99%. A diagnosis of hypohidrotic ectodermal dysplasia was also excluded (97.5% probability) by DNA and linkage analyses from a sample of cord blood from an at-risk male; a similar approach can be taken for prenatal diagnosis of the disorder.

Hypohidrotic ectodermal dysplasia. Clinical study of a family of 30 over three generations

A family carrying the X-linked gene for hypohidrotic ectodermal dysplasia (hereditary ectodermal polydysplasia or Christ-Siemens-Touraine syndrome) over three generations was monitored for more than 15 years. Two prenatal diagnoses were carried out by fetoscopy on skin biopsies. Polymorphic probes were used in the segregation analysis of the Xq11-21 region carried out on 30 members of the family. Current screening possibilities for the carriers and prenatal diagnosis are discussed.

Genetic mapping of anhidrotic ectodermal dysplasia: DXS159, a closely linked proximal marker

Three families with anhidrotic ectodermal dysplasia (AED) have been studied by linkage analysis with seven polymorphic DNA markers from the Xp11-q21 region. Previously reported linkage to DXYS1 (Xq13-q21) has been confirmed (z (theta) = 4.08 at theta = 0.05) and we have also established linkage to another polymorphic locus, DXS159, located in Xq11-q12 (z (theta) = 4.28 at theta = 0.05). Physical mapping places DSX159 proximal to the Xq12 breakpoint of an X autosome translocation found in a female with clinical signs of ectodermal dysplasia. Of all markers that have been used in linkage analysis of AED, DXS159 would appear the closest on the proximal side of the disease locus.

Hypohidrotic ectodermal dysplasia: a genealogic, stereomicroscope, and scanning electron microscope study

This is a report of three patients with hypohidrotic ectodermal dysplasia, or Christ-Siemens-Touraine syndrome, their genealogic backgrounds and the stereomicroscope and scanning electron microscopic appearances of the hair, the skin of their fingertips and palms as well as skin studies of members of their families. The skin morphology was recorded by means of silicone monomer rubber impressions and epoxy resin dyes. In two of the patients the disease was acquired by X-linked inheritance, while in the third, a boy, it appeared to follow an autosomal dominant pattern. Defects of the skin of the fingertips and palms of the propositi and members of the families included abnormalities of the morphology and pattern of the epidermal ridges, reduction of sweat pores varying from 13 to 87% of normal, and changed anatomy of the openings of the sweat glands. The openings were shallow and with less whorling compared to the normal, funnel-shaped sweat pores. Among the sweat pores, micropores, or openings with an average diameter of 5.3 micrometers, were observed. One of the propositi and the affected father of another had orifices on their fingertips resembling hair sheaths. Two propositi and the affected father of one exhibited grooving of the hair. The findings confirm the necessity for genealogic investigations in patients with or suspected of having the disease in order to advise parents or prospective parents. They also illustrate the usefulness of stereomicroscopy and scanning electron microscopy in observing skin and hair abnormalities.

Congenital alopecia, seizures, and psychomotor retardation in three siblings

Three siblings, devoid of hair at birth, had an unusual autosomal recessive disorder characterized by universal congenital alopecia, microcephaly, seizures, psychomotor retardation, and severe growth failure. Metabolic and chromosome studies were normal. Skin biopsies disclosed immature hair follicles, some of which were filled with keratotic material but had no hair shafts. Neuropathologic features included cerebral cortical hypoplasia, neuronal depletion, and microcalcifications. The familial occurrence of universal congenital alopecia conjoined with nonprogressive central nervous system abnormalities in this and other kindreds defines a nosologic group of neurocutaneous disorders in which congenital alopecia is the solitary cutaneous manifestation.

Close linkage between X-linked ectodermal dysplasia and a cloned DNA sequence detecting a two allele restriction fragment length polymorphism in the region Xp11-q12

EDA (ectodermal dysplasia, anhidrotic) is an X-linked recessive disorder characterized by hypohidrosis, hypoor anodontia, and hypotrichosis. A possible linkage between the gene for EDA and a number of restriction fragment length polymorphisms (RFLPs) spread over the X chromosome was investigated in two Danish families segregating EDA. No recombination between the gene for EDA and our probe pTAK8, which detects a two allele polymorphism in the region Xp11-q12, was found in nine informative meiotic events (seven of which are phase known), giving a maximal lod score of 2.41 at a recombination fraction of 0.00. This juxtacentromeric location of the gene for EDA agrees well with the linkage data obtained with the other markers used in this study.

Gene localisation of X-linked hypohidrotic ectodermal dysplasia (C-S-T syndrome)

Genetic linkage studies were carried out in families with X-linked hypohidrotic ectodermal dysplasia (C-S-T syndrome). A DNA probe DXYS1 (pDP34), which maps both to the proximal part of the long arm of the X chromosome, Xq13-Xq21, and proximally on Yp, was used to detect a TaqI restriction fragment length polymorphism of the X-chromosomal locus in the DNA samples from 11 families. This locus was found to be closely linked to the X-linked hypohidrotic ectodermal dysplasia locus, with a lod score of 2.66 at recombination fraction (theta) of 0.06 (90% confidence limits 0.01-0.26). Only one crossover was observed in nineteen meioses. This indicates that the probe DXYS1 is closely linked to the X-linked hypohidrotic ectodermal dysplasia locus and is likely to facilitate carrier detection and prenatal diagnosis tests.

Expression of X-linked hypohidrotic ectodermal dysplasia in six males and in their mothers

Six male patients with confirmed X-linked hypohidrotic ectodermal dysplasia and their mothers were studied to determine the variation of expressivity in patients and heterozygotes, major problems of the patients, and to find a clue to pathogenesis. The number of teeth, conic in shape, in patients varied from none to 14. In addition to hypohidrosis and hypotrichosis, dry skin, reduced salivation, hoarseness and hypoplasia of the nipples were common signs. Five patients had frequent respiratory infections. The mothers lacked more than four permanent teeth, one mother had hypodontia in the deciduous dentition. The sweat pore counts were low in patients, and lower than normal in the mothers. All patients carried beta-hemolytic streptococci, four of them group A either in nose or pharynx, without symptoms. Immunoglobulin values, including IgA were normal in serum and saliva. Unexpectedly, serum parathyroid hormone concentrations both in patients and mothers were low. The major problem of the families was the risk of hyperpyrexia due to hypohidrosis, but the patients' concern was mostly because of their facial appearance.

Lyonization and the lines of Blaschko

The lines of Blaschko represent a nonrandom developmental pattern of the skin fundamentally differing from the system of dermatomes. Many nevoid skin lesions display an arrangement following these lines. This is a review of case reports providing photographically documented evidence that the lines of Blaschko become manifest in the heterozygous state of various X-linked gene defects such as incontinentia pigmenti, focal dermal hypoplasia, X-linked dominant chondrodysplasia punctata, X-linked hypohidrotic ectodermal dysplasia, and Menkes syndrome. Hence, a causal relationship between lyonization and the lines of Blaschko seems quite obvious. Although it should be borne in mind that other genetic mechanisms such as somatic mutations or chimerism may give rise to the same linear pattern, the datable embryologic event of X-inactivation seems most suitable to explain the origin and nature of the lines of Blaschko. Apparently, in women affected with X-linked skin disorders the lines of Blaschko visualize the clonal proliferation of two functionally different populations of cells during early embryogenesis of the skin. The typical dorsal V-shape and the abdominal S-figure of these lines may result from an interference of the transversal coherent proliferation with the longitudinal growth and flexion of the embryo. In contrast to Blaschko's original assumption, it is now clear that these lines are independent from the metameric structure of the human body. Obviously, they represent a marker of the normal development of human skin. Therefore, a thorough study of the distribution pattern of X-linked skin disorders in women may give us a better insight into the early embryogeny of the human integument.

Manifestation of the lines of Blaschko in women heterozygous for X-linked hypohidrotic ectodermal dysplasia

For the detection of the carrier state of X-linked hypohidrotic ectodermal dysplasia, sweat pore counts on fingertips or palms have been used in the past. The results obtained, however, were sometimes difficult to interpret. We here describe a more reliable method, using the entire back as a test area. We provide evidence that the distribution of sweat pores in carriers is not simply patchy. In four heterozygous women we were able to demonstrate a linear distribution of hypohidrotic areas. This pattern followed the lines of Blaschko, forming a typical V-shape over the spine. Apparently, these lines reflect the dorsoventral outgrowth of two functionally different populations of cells during early embryogenesis.

Marshall syndrome: a condition resembling congenital syphilis

Marshall syndrome (ectodermal dysplasia) was diagnosed in a 14-year-old boy and is thought to be the first case reported from West Africa. Because of the saddle-nose deformity and bilateral cataracts all patients suspected of having congenital syphilis should be investigated for ocular or auditory defects, which would confirm the diagnosis of ectodermal dysplasia.

Principles of genetics as applied to dermatologic diseases

Skin diseases are frequently genetic in origin; knowing basic genetic principles allows the clinician to understand hundreds of diverse conditions. The structural basis of genetic disease is related to the multiple steps in DNA replication, messenger RNA (m-RNA) production and modification, protein synthesis, and the posttranslational modification of proteins. The multiple steps in these processes are reviewed. Metabolic processes are connected and interconnected by pathways and networks. The general principles of their control are discussed. The modes of inheritance and their distinguishing characteristics are emphasized, as are factors causing variability among those with the same genetic disease. Tables categorizing many genetic diseases are presented, as is a detailed guide to the literature relevant to modern dermatologic genetics.

A genetic study of anodontia in X-linked hypohidrotic ectodermal dysplasia

Dental examinations and tooth measurements were conducted on 16 mothers, 10 fathers, and 23 affected males in 15 families with X-linked hypohidrotic ectodermal dysplasia. Small teeth and congenital missing teeth were sufficiently consistent findings in obligate heterozygotes to suggest that carriers can usually be recognized by clinical criteria.

Non-inactivation of an x-chromosome locus in man

Cloned fibroblasts from women heterozygous for X-linked ichthyosis (steroid sulfatase deficiency) were examined to see whether or not this locus is subject to X-inactivation. Of 103 clones examined, all had normal levels of steroid sulfatase activity. Two of the women studied were also heterozygous for glucose-6-phosphate dehydrogenase deficiency. This allowed the demonstration that both X chromosomes were represented as the active X in various clones and that selection did not account for these findings. Thus, the steroid sulfatase locus, like the Xga locus to which it is linked, appears to escape X-inactivation in man.

Christ-Siemens-Touraine syndrome--a clinical and genetic analysis of a large Brazilian kindred: III. Carrier detection

Detection of carriers of the Christ-Siemens-Touraine syndrome on the basis of data of physical examination has been possible in about 60--70% of the cases reported in 44 papers, including a large Brazilian kindred studied by the authors. Partial data, however, showed detection values ranging from 42% to 84%.

Treatment of hyperhidrosis with topical methenamine

Idiopathic palmar and plantar hyperhidrosis is a relatively common disorder of eccrine sweat gland function. Treatment with glutaraldehyde of formaldehyde, although successful, may cause undesirable side effects. Methenamine is a polycyclic organic compound which release ammonia and formaldehyde at acid pH. Five per cent methenamine in a firm stick gel, applied daily to one palmar or plantar surface of 109 patients with hyperhidrosis, resulted in significantly less sweating after one month. No patients were sensitized to formaldehyde.

The syndrome of ankyloblepharon, ectodermal defects and cleft lip and palate: an autosomal dominant condition

Seven patients from four families are reported who had an inherited condition of which the main features were ankyloblepharon, ectodermal defects and cleft lip and palate. The ectodermal defects were partial or complete hair loss, absent or dystrophic nails, pointed widely spaced teeth and partial anhidrosis. Associated anomalies included lacrimal duct atresia, supernumerary nipples, syndactyly and auricular deformities. The inheritance of this abnormality was consistent with that of an autosomal dominant trait. The relationship between this and similar syndromes is discussed.

Herediatary anhidrotic ectodermal dysplasia. Studies in a Nigerian famil

Studies in a Nigerian family with hereditary anhidrous ectodermal dysplasia are reported. Microscopical examinations of finger tips for sweat pores were diagnostic in phenotypes, and it is suggested that this simple nonsurgical procedure is a preferred alternative to skin biopsies in the diagnosis of the syndrome. The clinical implications of a tropical environment for the syndrome, as well as the factors that may favour maintenance of the gene in such an environment are discussed.