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.

Poorly understood and often miscategorized congenital umbilical cord hernia: an alternative repair method.

PURPOSE: Umbilical cord hernia is poorly understood and often miscategorized as "omphalocele minor". Careless clamping of the cord leads to iatrogenic gut injury in the situation of umbilical cord hernia. This study aimed to determine the characteristics and outcomes of umbilical cord hernias. We also highlight an alternative repair method for umbilical cord hernias. METHODS: We recorded 15 cases of umbilical cord hernias over 10 years. The patients' data were retrospectively reviewed, and preoperative preparation of the newborn, gestational age, birth weight, other associated malformations, surgical technique used, enteral nutrition, and length of hospitalization were recorded. RESULTS: This study included 15 neonates with umbilical cord hernias. The mean gestational age at the time of referral was 38.2 ± 2.1

The gene defective in anhidrotic ectodermal dysplasia is expressed in the developing epithelium, neuroectoderm, thymus, and bone.

Anhidrotic ectodermal dysplasia (EDA) is characterized by defects in the development of teeth, hair, and sweat glands. To study the expression of the human gene defective in EDA in human fetal development (Weeks 6-23 of gestational age) and in adult tissues, in situ hybridization and immunohistochemistry were used. First signs of expression were detected at Week 8 in epidermis and in neuroectodermal cells. Starting at Week 12, osteoblasts and thymus were positive for EDA mRNA. Hair follicles expressed EDA mRNA from 18 weeks. The presence of the EDA protein coincided with mRNA expression in the tissues examined. The expression pattern of the EDA gene is consistent with typical involvement of the skin in the syndrome. However, the expression is not limited to the ectodermal tissues and many sites of expression are not obviously reflected in the clinical features of the syndrome.

Proficiency testing in immunohematology in Ontario, Canada, 1975-1977.

Since April 1975 the proficiency of laboratories in Ontario that perform immunohematology tests has been assessed. While the majority of test samples have required only ABO and Rh(D) typing, others have posed problems. The error rate in uncomplicated ABO typing was 1.3/1,000 in 17,479 tests and that in straightforward Rh(D) grouping, 6.6/1,000 in 17,757 tests. False-negative (36/1,000) and false-positive (1.4/1,000) direct antiglobulin tests occurred. Errors in detection of strong alloantibodies (e.g., anti-D) were 19.7, 10.2 and 5.1/1,000 in three test samples. A2B or A2 cells with anti-A1 in serum were sent out in two surveys; error rates in ABO interpretation were 189 and 52/1,000, respectively. Laboratories also experienced difficulty in interpreting the Rh(D) type of cells with positive antiglobulin tests. These surveys have had several effects: (1) laboratories with poor performance have been identified, (2) patterns of practice have been influenced, (3) areas of ignorance have been identified, and (4) a stimulus has been provided for continuing education in immunohematology.

Neuropeptide S receptor 1 (NPSR1) activates cancer-related pathways and is widely expressed in neuroendocrine tumors.

Neuroendocrine tumors (NETs) arise from disseminated neuroendocrine cells and express general and specific neuroendocrine markers. Neuropeptide S receptor 1 (NPSR1) is expressed in neuroendocrine cells and its ligand neuropeptide S (NPS) affects cell proliferation. Our aim was to study whether NPS/NPSR1 could be used as a biomarker for neuroendocrine neoplasms and to identify the gene pathways affected by NPS/NPSR1. We collected a cohort of NETs comprised of 91 samples from endocrine glands, digestive tract, skin, and lung. Tumor type was validated by immunostaining of chromogranin-A and synaptophysin expression and tumor grade was analyzed by Ki-67 proliferation index. NPS and NPSR1 expression was quantified by immunohistochemistry using polyclonal antibodies against NPS and monoclonal antibodies against the amino-terminus and carboxy-terminus of NPSR1 isoform A (NPSR1-A). The effects of NPS on downstream signaling were studied in a human SH-SY5Y neuroblastoma cell line which overexpresses NPSR1-A and is of neuroendocrine origin. NPSR1 and NPS were expressed in most NET tissues, with the exception of adrenal pheochromocytomas in which NPS/NPSR1 immunoreactivity was very low. Transcriptome analysis of NPSR1-A overexpressing cells revealed that mitogen-activated protein kinase (MAPK) pathways, circadian activity, focal adhesion, transforming growth factor beta, and cytokine-cytokine interactions were the most altered gene pathways after NPS stimulation. Our results show that NETs are a source of NPS and NPSR1, and that NPS affects cancer-related pathways.

Anhidrotic ectodermal dysplasia (EDA) protein expressed in MCF-7 cells associates with cell membrane and induces rounding.

Anhidrotic ectodermal dysplasia (EDA) is a rare X-linked recessive disorder characterized by the absence or hypoplasia of hair, teeth and sweat glands. The gene responsible for the disorder has recently been cloned. The predicted gene product is a 135 amino acid protein with no significant homology to previously known proteins. As a first step to analyze function, we have studied the subcellular localization of the EDA gene product expressed in two epithelial cell lines, COS-1 and MCF-7. Biochemical fractionation and confocal imaging analysis show that, in agreement with a single putative transmembrane domain inferred from its sequence, the EDA protein is transported to the plasma membrane. Moreover, in MCF-7 cells expression of EDA is associated with rounding and detachment of the cells. These results suggest that the EDA protein may be involved in cellular dynamics or signaling.

Differential expression during embryogenesis of three genes clustered in the Ras1 region of Drosophila melanogaster.

Transcription mapping and nucleotide sequence analysis reveal that the genomic region of the Drosophila Ras1 gene contains a cluster of three closely localized genes. A gene termed Rlb1 is located nearby and upstream of Ras1, and is oriented in the opposite polarity relative to Ras1. In addition, a third gene termed Rlc1, is found at a very close proximity downstream to Rlb1. Ras1, the homologue of the human transforming ras genes, has been shown to be active in the posterior termini of the Drosophila embryo and in the eye imaginal disc in pathways of cell fate determination. We demonstrate that during embryogenesis Ras1 transcripts are restricted mainly to the embryonic central nervous system, suggesting that the gene product also may have a role in these nerve cells. Rlb1 encodes for a novel, lysine-rich basic protein. It is expressed mainly in the developing midgut and in the somatic mesoderm. Rlc1 also encodes for a novel, basic protein. The expression of Rlc1 during embryogenesis is similar, but not identical, to the expression pattern detected for Ras1. The vertebrate p21Ras proteins are bound to the inner face of the cell membrane. Ras1, the Drosophila homologue of p21, and the Rlb1 protein, are also non-cytoplasmic, membranous proteins. Rlb1 is found in the cell membrane of larval midgut epithelial cells. In addition, Rlb1 is detected in the nuclei of these cells, and in the nuclei of the midgut imaginal cells.

Ectodysplasin is a collagenous trimeric type II membrane protein with a tumor necrosis factor-like domain and co-localizes with cytoskeletal structures at lateral and apical surfaces of cells.

Anhidrotic ectodermal dysplasia (EDA) is a human genetic disorder of impaired ectodermal appendage development. The EDA gene encodes isoforms of a novel transmembrane protein, ectodysplasin. The sequence of the longest isoform includes an interrupted collagenous domain of 19 Gly-X-Y repeats and a motif conserved in the tumor necrosis factor (TNF)-related ligand family. In order to understand better the function of the ectodysplasin protein molecule and its domains, we have studied the processing and localization of wild-type and mutated isoforms in transfected human fetal kidney 293 and monkey kidney COS-1 cells. Similar to other members of collagenous membrane proteins and members of TNF-related ligands, ectodysplasin is a type II membrane protein and it forms trimers. The membrane localization of ectodysplasin is asymmetrical: it is found on the apical and lateral surfaces of the cells where it co-localizes with cytoskeletal structures. The TNF-like motif and cysteines found near the C-terminus are necessary for correct transport to the cell membrane, but the intracellular and collagenous domains are not required for the localization pattern. Our results suggest that ectodysplasin is a new member in the TNF-related ligand family involved in the early epithelial-mesenchymal interaction that regulates ectodermal appendage formation.

Expression of the anhidrotic ectodermal dysplasia gene is reduced in skin cancer coinciding with reduced E-cadherin.

X-linked anhidrotic ectodermal dysplasia (EDA) is characterized by defects in the development of hair, teeth, and sweat glands. We have recently cloned the gene for EDA by positional cloning. The EDA gene encodes a transmembrane protein with a putative role in epithelial mesenchymal interactions. Since EDA could play a role in cell-cell or cell-matrix adhesion, acantholytic skin diseases and several types of non-invasive and invasive skin cancers were studied using in situ hybridization. Because of the observation that the promoter region of the EDA gene contains a binding site for LEF-1, which is involved in the signaling through E-cadherin/beta catenin complex, we compared the expression of EDA with immunolocalization for E-cadherin (E-CD). EDA expression during hair growth cycle, in benign adnexal tumors, and neuroectoderm-derived nevus cells was also examined. Our findings indicate that EDA expression is less abundant in malignant tumors, including basal and squamous cell carcinomas and melanoma, and in acantholytic keratinocytes compared to normal epidermis. The reduction in expression also coincides with diminished E-CD staining in all malignant cell types and in acantholytic cells. Our results suggest that EDA protein functions in the regulation of epithelial cell contacts and that it may be associated with the E-CD signaling pathway.

The anhidrotic ectodermal dysplasia gene (EDA) undergoes alternative splicing and encodes ectodysplasin-A with deletion mutations in collagenous repeats.

Anhidrotic ectodermal dysplasia (EDA) is an X-linked recessive disorder which affects ectodermal structures. A cDNA encoding a 135 amino acid protein with mutations in 5-10% of EDA patients has been reported. We have built up a complete splicing map of the EDA gene and characterized the longest and what most probably represents the full-length EDA transcript, EDA-A. It encodes a 391 amino acid transmembrane protein with a short collagenous domain, (Gly-X-Y)19, and is highly homologous to the protein mutated in Tabby mice (Ta-A). Four new transcripts that code for truncated proteins lacking the collagenous domain were also detected. The splice variants show different expression patterns in eight tissues analyzed, suggesting a regulatory mechanism for gene expression. The EDA-A form of the protein is transported to the cell membrane and induces rounding of the cells, properties also associated with the 135 amino acid isoform. We have determined the genomic organization and the exon-intron boundaries of the EDA gene. SSCP analysis of the nine exons corresponding to EDA-A allowed the identification of mutations in 12 out of 15 EDA patients. Interestingly, three mutations removed either two or four of the Gly-X-Y repeats without interrupting the reading frame, thus suggesting a functional role for the collagenous domain. Our results will allow mutation diagnostics in the majority of patients.

A system for proficiency testing in immunohaematology.

A compulsory programme of proficiency testing in immunohaematology has been conducted for the last 4 years. The collection, processing and analysis of testing data reported by participating laboratories depends on a computer-based system, which allows the generation of reports for participants and working documents essential to the functioning of a committee which supervises the operation of the programme. The options open to the committee in coping with laboratories with poor performance are summarized.

The Tabby phenotype is caused by mutation in a mouse homologue of the EDA gene that reveals novel mouse and human exons and encodes a protein (ectodysplasin-A) with collagenous domains.

Mouse Tabby (Ta) and X chromosome-linked human EDA share the features of hypoplastic hair, teeth, and eccrine sweat glands. We have cloned the Ta gene and find it to be homologous to the EDA gene. The gene is altered in two Ta alleles with a point mutation or a deletion. The gene is expressed in developing teeth and epidermis; no expression is seen in corresponding tissues from Ta mice. Ta and EDA genes both encode alternatively spliced forms; novel exons now extend the 3' end of the EDA gene. All transcripts recovered have the same 5' exon. The longest Ta cDNA encodes a 391-residue transmembrane protein, ectodysplasin-A, containing 19 Gly-Xaa-Yaa repeats. The isoforms of ectodysplasin-A may correlate with differential roles during embryonic development.

Proficiency testing in immunohaematology in Ontario, Canada, 1977-1979.

An analysis of the results of a compulsory proficiency testing programme in immunohaematology is presented. Error rates have been calculated for the determination of ABO and Rh(D) groups, the direct antiglobulin test and antibody detection according to defined criteria. The introduction of proficiency testing has been associated with alterations in error rates for some determinations. An educational programme introduced for laboratories with poor performance has proved effective in improving their results in the proficiency testing programme.