bromochloroacetic-acid and Genetic-Diseases--Inborn

Keratin expression in human tissues and neoplasms Keratin filaments constitute type I and type II intermediate filaments (IFs), with at least 20 subtypes named keratin 1-20. Since certain keratin subtypes are only expressed in some normal human tissues but not others, and vice versa, various tissues have been subclassified according to the pattern of keratin staining. Simple epithelia generally express the simple epithelial keratins 7, 18, 19, and 20, while complex epithelia express complex epithelial keratins 5/6, 10, 14, and 15. When an epithelium undergoes malignant transformation, its keratin profile usually remains constant. The constitution and expression patterns of keratin filaments in human epithelial neoplasms are complex and often distinctive. In this article, we first briefly review the molecular and cell biology of keratin filaments. We then focus on the expression patterns of keratin filaments in various human neoplasms.

Topics: Chromosome Mapping; Epithelium; Gene Expression; Genetic Diseases, Inborn; Humans; Keratins; Mutation; Neoplasms

The cytoplasm of animal cells is structured by a scaffolding composed of actin microfilaments, microtubules, and intermediate filaments. Intermediate filaments, so named because their 10-nanometer diameter is intermediate between that of microfilaments (6 nanometers) and microtubules (23 nanometers), assemble into an anastomosed network within the cytoplasm. In combination with a recently identified class of cross-linking proteins that mediate interactions between intermediate filaments and the other cytoskeletal networks, evidence is reviewed here that intermediate filaments provide a flexible intracellular scaffolding whose function is to structure cytoplasm and to resist stresses externally applied to the cell. Mutations that weaken this structural framework increase the risk of cell rupture and cause a variety of human disorders.

Topics: Animals; Axons; Cytoplasm; Cytoskeletal Proteins; Disease; Genetic Diseases, Inborn; Humans; Intermediate Filament Proteins; Intermediate Filaments; Keratinocytes; Keratins; Microtubules; Mutation; Neurons

Since the time when I was a postdoctoral fellow under the supervision of Dr. Howard Green, then at the Massachusetts Institute of Technology, I have been interested in understanding the molecular mechanisms underlying growth, differentiation, and development in the mammalian ectoderm. The ectoderm gives rise to epidermal keratinocytes and to neurons, which are the only two cell types of the body that devote most of their protein-synthesizing machinery to developing an elaborate cytoskeletal architecture composed of 10-nm intermediate filaments (IFs). Our interest is in understanding the architecture of the cytoskeleton in keratinocytes and in neurons, and in elucidating how perturbations in this architecture can lead to degenerative diseases of the skin and the nervous system. I will concentrate on the intermediate filament network of the skin and its associated genetic disorders, since this has been a long-standing interest of my laboratory at the University of Chicago.

Topics: Animals; Cytoskeleton; Epidermolysis Bullosa Simplex; Genetic Diseases, Inborn; Humans; Keratins; Mice; Nervous System Diseases; Skin Diseases

Topics: Animals; Cell Survival; Genetic Diseases, Inborn; Humans; Intermediate Filament Proteins; Intermediate Filaments; Keratins; Mutation; Skin Diseases

We have limited the scope of this article to those disorders that have already been successfully diagnosed or excluded in utero. We currently have the potential to diagnose a number of others for which the opportunity has not yet arisen. If a biochemical, morphologic, chromosomal, or DNA alteration is known for a specific condition and is likely to be expressed in one of the fetal tissues or secretions, attempt at prenatal diagnosis is reasonable. Our ability to detect the inherited disorders of the skin in utero will continue to improve both in the number of specific disorders successfully diagnosed or excluded and in the increasingly earlier stages of pregnancy at which the disorder can be detected. Advances in instrumentation will, it is hoped, decrease the risk of the invasive methods of prenatal diagnosis, and improvement in noninvasive methods, such as maternal serum screening, may eliminate the need for invasive procedures altogether. Detection of useful DNA polymorphisms linked to genes for specific genodermatoses and development of specific gene probes will improve the accuracy of diagnosis and reduce the need for specific fetal tissues. The entire genome of an individual is present in each cell, even though a specific gene product may not be expressed in that cell. Thus, DNA restriction endonuclease studies can be performed on amniotic fluid cells, chorionic villi, fetal cells in maternal circulation, and fetal tissues with equal facility. The usefulness of prenatal diagnosis will always be limited by the ability to detect pregnancies at risk. If carrier detection is unavailable, the only way to identify couples at risk for offspring with an autosomal recessive condition is by the birth of an affected child. For autosomal dominant and X-linked recessive and dominant conditions, new mutations will continue to occur. As mentioned previously, screening of all pregnancies for all defects is not possible now and is unlikely ever to be feasible, either economically or technically. The reliability of prenatal diagnosis will continue to depend upon accurate diagnosis in the index case and upon the availability of a specific and sensitive test (or tests), with no overlap in values between heterozygotes and homozygotes for autosomal recessive conditions or between normal and affected fetuses with autosomal dominant and X-linked recessive disorders. Correct interpretation of test results is subject to experience, recognition of artifact, and variation in t

Topics: Amniocentesis; Blood Chemical Analysis; Chorionic Villi; Ectodermal Dysplasia; Female; Fetoscopy; Genetic Diseases, Inborn; Humans; Keratins; Male; Pregnancy; Prenatal Diagnosis; Skin Diseases, Vesiculobullous; Ultrasonography

Topics: Animals; Cell Differentiation; Electrophoresis, Polyacrylamide Gel; Epidermis; Female; Filaggrin Proteins; Genetic Diseases, Inborn; Histocytochemistry; Humans; Immunologic Techniques; Intermediate Filament Proteins; Intermediate Filaments; Keratins; Pregnancy; Prenatal Diagnosis

RNA interference offers a novel approach for treating genetic disorders including the rare monogenic skin disorder pachyonychia congenita (PC). PC is caused by mutations in keratin 6a (K6a), K6b, K16, and K17 genes, including small deletions and single nucleotide changes. Transfection experiments of a fusion gene consisting of K6a and a yellow fluorescent reporter (YFP) resulted in normal keratin filament formation in transfected cells as assayed by fluorescence microscopy. Similar constructs containing a single nucleotide change (N171K) or a three-nucleotide deletion (N171del) showed keratin aggregate formation. Mutant-specific small inhibitory RNAs (siRNAs) effectively targeted these sites. These studies suggest that siRNAs can discriminate single nucleotide mutations and further suggest that "designer siRNAs" may allow effective treatment of a host of genetic disorders including PC.

Topics: Cell Line, Tumor; Dimerization; Genetic Diseases, Inborn; Humans; Keratin-6; Keratins; Mutagenesis, Site-Directed; Mutation; Pachyonychia Congenita; RNA, Messenger; RNA, Small Interfering; Transfection

Topics: Animals; Epidermis; Genetic Diseases, Inborn; Humans; Keratins; Skin Diseases

Cannon's disease or white sponge naevus is a relatively rare genetically determined skin disorder. It is inherited as an autosomal dominant trait that displays a high degree of penetrance and expressivity. This article describes cases of Cannon's disease in a mother and her son.

Topics: Adult; Burns, Chemical; Candidiasis, Oral; Child, Preschool; Diagnosis, Differential; Female; Genetic Diseases, Inborn; Humans; Keratins; Keratosis; Leukoplakia, Oral; Male; Mouth Diseases; Mouth Mucosa; Mutation; Pedigree

Topics: Base Sequence; DNA Mutational Analysis; DNA, Complementary; Female; Genetic Diseases, Inborn; Genetic Linkage; Genetic Testing; Genotype; Humans; Intermediate Filament Proteins; Intermediate Filaments; Keratins; Lamins; Male; Microsatellite Repeats; Molecular Biology; Mutation; Pedigree; Phenotype; Polymerase Chain Reaction; Polymorphism, Single Nucleotide; Pregnancy; RNA, Messenger

It has recently been demonstrated that genetic defects in keratin genes cause a number of different skin disorders, including epidermolysis bullosa simplex (EBS), epidermolytic hyperkeratosis (EH), the EH form of epidermal nevi, epidermolytic and non-epidermolytic forms of palmoplantar keratoderma (EPPK and PPK) and pachyonychia congenita (PC). In this review, I describe the research that led to this discovery.

Topics: Animals; Genetic Diseases, Inborn; Humans; Keratins

Aggregation of tonofilaments within epidermal keratinocytes is a characteristic histologic feature of epidermolytic hyperkeratosis including the generalized form known as bullous congenital ichthyosiform erythroderma. The histologic distribution and the keratin composition of the altered tonofilaments were investigated to determine whether the aggregation was specific to any particular keratin(s). Skin samples from seven patients and one mid-trimester fetus with generalized epidermolytic hyperkeratosis, and from one patient with a localized or "nevoid" form of epidermolytic hyperkeratosis, were analyzed by using various microscopical and immunocytochemical methods. A conjunctival sample and cultured epidermal keratinocytes from one patient with generalized epidermolytic hyperkeratosis were also examined by electron microscopy and immunocytochemistry. Ultrastructurally, tonofilament aggregates were distributed within the suprabasal stratified epithelial cell layers of the epidermis, of the infundibular part of outer root sheaths, and of the sebaceous ducts and sweat ducts, selectively following the known distribution pattern of keratins K1 and K10. The abnormal tonofilaments were not found in any other cutaneous epithelia, in conjunctival epithelium, or in cultured keratinocytes, where K1 and K10 are absent or only minimally expressed. Immunoelectron microscopy showed that among the keratins detected in suprabasal epidermolytic hyperkeratosis epidermis (K1/K5/K10/K14/K16), the aggregated tonofilaments predominantly expressed K1 and K10 rather than other keratins. These results suggest that the keratin filament abnormality in epidermolytic hyperkeratosis principally involves K1 and K10 and raise the question whether epidermolytic hyperkeratosis might be primarily a disorder of one or both of these keratins.

Topics: Adolescent; Adult; Antibodies, Monoclonal; Cytoskeleton; Female; Fetus; Genetic Diseases, Inborn; Humans; Ichthyosiform Erythroderma, Congenital; Immunohistochemistry; Infant; Infant, Newborn; Keratins; Male; Microscopy, Electron; Microscopy, Immunoelectron; Skin

Topics: Alopecia; Biomechanical Phenomena; Elasticity; Female; Genetic Diseases, Inborn; Hair; Homocystinuria; Humans; Hyperthyroidism; Hypothyroidism; Ichthyosis; Keratins; Keratosis; Male; Oxidation-Reduction; Skin Diseases; Ultrasonography; X-Ray Diffraction