- Email: [email protected]
S100 Keratin gene mutations and epidermolysis bullosa
Symposia
ISO96
Etiopathogenic
E. Haneke. Dept Dermatol,
- Epidermolysis
problems in onychomycoses Univ
Witten/Herdecke,
Wuppertal,
Germany
Onychomycoses are by far the most frequent nail diseases. Of all dermatomycoses, they are also the most difficult to treat. Chronic onychomycoses could not be induced experimentally giving strong evidence for the crucial role of predisposing factors. Dermatophytes, other moulds and yeasts can infect the nails though to different degrees. The clinical appearance rarely allows the pathogenic organism to be specified. Fungi can invade the nail via the hyponychium, cuticleeponychium, or surface causing different patterns of infection that require different management approaches. Many problems concerning fungal nail infections wait to get clarified: why are some nails spared, why do the fungi progress to a certain extent and then stop, why does the infection advance in some nails whereas it remains unchanged in others, why do some nails respond to treatment whereas others do not. These and many more questions have to be investigated in order to enhance our knowledge and improve treatment responses. I SO97 The pharmacokinetics
s2.5
Bullosa
of treatment failure in patients with oral or vaginal candidosis have given rise to increased concern about resistance. Acquired azole drug resistance has been recorded with several organisms, particularly Candida albicans and C. glabrata, in situations where fluconazole treatment has been given for long periods of time in the face of persistent or recurrent infection. Many reports have involved AIDS patients with low CD4 counts who had received repeated short courses or more prolonged treatment with fluconazole for oral or oesophageal infection with C. albicans. Molecular typing has demonstrated transmission of resistant strains between HIV-positive partners, but it remains unclear whether resistant strains persist if transmitted to HIV-negative individuals. Management of AIDS patients with fluconazole-resistant oral infection can be difficult, but C. albicans often remains susceptible to other azoles. In contrast, the fluconazole-resistant strains of Candida glabrata that have been recovered from some women with recurrent vaginal candidosis are usually cross-resistant to all azole drugs. At present, acquired drug resistance does not appear to be a major problem in other clinical settings.
Epidermolysis Bullosa
and penetration of
antifungal drugs
Jan Faergemann. Department University
Hospital,
of Dermatology,
Gothenburg,
Overview for symposium on epidermolysis I SO99 bullosa
Sahlgrenska
Sweden
Details of skin distribution of oral antifungal drugs should provide the basis for a more rational, pharmacodynamic-oriented approach to antifungal therapy than the use of traditional blood levels. Fluconazole is a broad spectrum, orally active triazole derivative developed by Pfizer. Skin pharmacokinetic results show that fluconazole reach the stratum corneum both through a direct diffusion and through sweat. Very high concentrations are obtained in the stratum corneum within hours after oral administration (23.4 pg/g), and fluconazole remains in the stratum comeum for a long time after seccesation of therapy. Recently very high concentrations (8.54 pg/g) have also been found in nails after weekly medication with 150 mg in the treatment of onychomycosis of the toenails. Itraconazole is an orally active triazole derivative developed by Janssen. It is lipophilic but found in lower concentrations in stratum comeum than both fluconazole and terbinafine. However, the levels in nails (0.93 pg/g) are comparable to terbinafine (0.39 @g/g) and it is also found there for several month after stop of therapy. Terbinafine, an orally active allylamine developed by Sandoz is orally active especially against dermatophytes. It is lipophilic and delivered to the stratum corneum through direct diffusion and in very high concentrations in sebum. It remain in the stratum comeum and especially in nails for a long time after stop of treatment.
SO98 Drug resistance and its clinical relevance D.W. Wamock. Mycology Laboratory
Service,
Bristol,
Reference UK
Laboratory,
Public
Health
Until the late 198Os, resistance to azole antifungals was an uncommon clinical problem and other factors were held to account for treatment failure or relapse. However, recent reports
R.A.J. Eady. St. John’s
Inst.
of Derm.
London,
UK
Epidermolysis bullosa (EB) comprises a number of genetically determined skin blistering disorders. Recently, there have been considerable advances in our understanding of the pathogenesis of the different forms of EB. This Session will cover some of the recently discovered genetic defects, especially as they relate to EB simplex and junctional EB and examine newer methods in treatment and diagnosis, including prenatal testing. On a more practical level, the organisation of a multi-disciplinary EB clinic and the nutritional requirements of EB patients will be discussed. The final presentation will explore the possibilities of developing new forms of treatment for EB, including gene therapy. I Si 00
Keratln gene mutations and epidermolysis bullosa
K.E. McKenna. Dept of Dermatology, Hospital
Group
Trust,
Craigavon,
Craigavon Area Northern Ireland
The cytoskeleton of epidermal cells consists of a network of keratin filaments. In the basal layer of the epidermis these filaments are composed of heterodimers of type I keratin K14 and type II keratin K5. Mutations of these keratins leads to aberrant keratin filament assembly and to basal cell cytolysis in Epidermolysis Bullosa Simplex (EBS) Experiments using transgenic mice have allowed prediction of clinical disease severity according to the site of mutation within the keratin protein structure. The Dowling-Meara and Koebner forms of EBS are characterized by generalised blistering. The former is more severe and electron-dense keratin aggregates are seen in the cell cytoplasm. Mutations in this
S26
Symposia
-
Epidetmolysis
form are clustered in the highly conserved ends of the central o-helical rod domains. In the Koebner form mutations tend to occur within the a-helical rod domains. In the milder, localised Weber-Cockayne form mutations are often found in non-helical regions. The identification of keratin gene mutations can now be applied to the prenatal diagnosis of EBS.
a dermatologist every three months should be performed for prevention of skin cancer. I S103 Nutritional requirements in epidermolysis
bullosa (EB) patients
Lesley Haynes. Great NHS
I Si 01
Recent advances in junctional epidermolysis bullosa
John A. M&ram. Thomas’s
Hospital,
St John’s London,
Institute UK
of Dermatology,
St
Junctional epidermolysis bullosa (JEB) is a clinically heterogeneous disorder, the pathogenesis of which involves mutations in the genes encoding a number of different structural macromolecules of the hemidesmosome-anchoring filament complex. The severe, lethal (Herlitz) form of JEB is caused by premature termination codon (PTC) mutations on both alleles of either the LAMA3, LAMB3 or LAMC2 genes which encode the CY~,83 or y2 polypeptide chains of laminin 5, respectively. Cases of nonlethal JEB, associated with chronic poorly healing trauma-induced erosions, may also arise due to laminin 5 mutations, usually involving a PTC on one allele, and a less disruptive mutation, such as a missense mutation, on the other allele. In addition, PTC mutations on both alleles of the 180~kDa bullous pemphigoid antigen gene, also known as type XVII collagen, (BPAG2/COL17Al) have been found in a subtype of nonlethal JEB known as generalized atrophic benign epidermolysis bullosa. Most recently, mutations in the (~6 and 84 integrin genes (ITGA6 and ITGB4) have been delineated in the variant of JEB associated with pyloric atresia. Knowledge of the molecular basis of JEB has important clinical implications for affected patients and their families. Determining specific gene abnormalities has lead to better genetic counselling, the development of DNA-based prenatal diagnosis, and a foundation for the planning newer forms of treatment, including somatic gene therapy. I S102 The organization of a multidisciplinary
Epidermolysis Bullosa clinic
Cl. Blanchet-Bardon.
Hdpital
Saint-Louis,
Paris,
France
The management of Epidermolysis Bullosa (EB), especially severe recessive dystrophic EB, requires a multidisciplinary staff. As soon as the baby is born correct diagnosis should be made by biopsy with electron microscopy and immunofluorescence. This biopsy will provide prognostic information leading in a case of severe recessive dystrophic EB to educate the parents to prevent further blistering, to establish adequate feeding and growth by the nutritionist and genetic counselling for the family. In early infancy, a multidisciplinary management has to be organized with the Dermatologist, Ophtalmologist, Handsurgeons, Stomatologist, Physiotherapist, Nutritionist, Gastroenterologist and Infectiologist, Nephrologist and Anesthesiologist. In addition this multidisciplinary approach includes social workers for social, school and work-integration. Later on in adulthood a special consultation and survey with
Bullosa
Trust,
London,
Ormond UK
Street Hospitalfor
Children
Two main factors potentially compromise nutritional status in EB:(a) the extent to which skin lesions, consequent losses of blood and serous fluid, and infections contribute to increased requirements and (b) the degree to which oral, oro-pharyngeal, oesophageal and gastro-intestinal complications limit intake. Malnutrition and growth failure should be avoidable (except in lethal junctional EB), with early dietary intervention (supplementation of energy, protein, iron, zinc, fibre and vitamins) and close monitoring (nutritional assessment, anthropometry, haematology and biochemistry). A multi-disciplinary approach is essential since factors such as poor skin care, gastro-oesophageal reflux, chronic constipation, anaemia etc. indirectly affect nutritional status. Many recessive dystrophic EB patients cannot maintain satisfactory progress without insertion of a ‘button’ gastrostomy. This type of intervention should be considered early. I S104 Prenatal diagnosis of epidermolysis bullosa R.A.J. Eady. St John’s Institute of Dermatology, UMDS, St Thomas’s
Hospital,
London,
UK
Fetal skin biopsy, initially performed under fetoscopic monitoring, and more recently using high resolution ultrasound guidance, has been the mainstay for the prenatal diagnosis (PND) of junctional EB (JEB) and dystrophic EB (DEB) over the past 17 years. However, following the recent discovery of the genetic causes of all the major forms of EB, DNA-based PND of JEB and DEB is now not only possible, but has been successfully used in the testing of a total of over 40 pregnancies in the few centres currently able to undertake this form of analysis. Chorion has identical DNA to the fetus, and chorionic villus sampling performed at 10-l 1 week’s gestation is an established method of obtaining an adequate amount of DNA for PND involving linkage analysis, mutation screening or direct sequencing. This approach can currently be used to search for mutations in any of the 6 genes causing JEB, or in the single collagen VII gene (COL7Al) underlying both dominant and recessive forms of DEB.
S105 1 The future of gene therapy for EB W.H.I. McLean. Epithelial Jefferson
Medical
College,
Genetics Group, Dept Dermatology, Philadelphia PA, USA
Despite a deluge of media attention, no case exists where gene therapy has completely cured a genetic disorder. Epidermolysis bullosa (EB) is a group of genodermatoses which are both clinically and genetically heterogeneous. Ten genes are now known to cause various forms of EB, facilitating the preven-
ISO96
Etiopathogenic
E. Haneke. Dept Dermatol,
- Epidermolysis
problems in onychomycoses Univ
Witten/Herdecke,
Wuppertal,
Germany
Onychomycoses are by far the most frequent nail diseases. Of all dermatomycoses, they are also the most difficult to treat. Chronic onychomycoses could not be induced experimentally giving strong evidence for the crucial role of predisposing factors. Dermatophytes, other moulds and yeasts can infect the nails though to different degrees. The clinical appearance rarely allows the pathogenic organism to be specified. Fungi can invade the nail via the hyponychium, cuticleeponychium, or surface causing different patterns of infection that require different management approaches. Many problems concerning fungal nail infections wait to get clarified: why are some nails spared, why do the fungi progress to a certain extent and then stop, why does the infection advance in some nails whereas it remains unchanged in others, why do some nails respond to treatment whereas others do not. These and many more questions have to be investigated in order to enhance our knowledge and improve treatment responses. I SO97 The pharmacokinetics
s2.5
Bullosa
of treatment failure in patients with oral or vaginal candidosis have given rise to increased concern about resistance. Acquired azole drug resistance has been recorded with several organisms, particularly Candida albicans and C. glabrata, in situations where fluconazole treatment has been given for long periods of time in the face of persistent or recurrent infection. Many reports have involved AIDS patients with low CD4 counts who had received repeated short courses or more prolonged treatment with fluconazole for oral or oesophageal infection with C. albicans. Molecular typing has demonstrated transmission of resistant strains between HIV-positive partners, but it remains unclear whether resistant strains persist if transmitted to HIV-negative individuals. Management of AIDS patients with fluconazole-resistant oral infection can be difficult, but C. albicans often remains susceptible to other azoles. In contrast, the fluconazole-resistant strains of Candida glabrata that have been recovered from some women with recurrent vaginal candidosis are usually cross-resistant to all azole drugs. At present, acquired drug resistance does not appear to be a major problem in other clinical settings.
Epidermolysis Bullosa
and penetration of
antifungal drugs
Jan Faergemann. Department University
Hospital,
of Dermatology,
Gothenburg,
Overview for symposium on epidermolysis I SO99 bullosa
Sahlgrenska
Sweden
Details of skin distribution of oral antifungal drugs should provide the basis for a more rational, pharmacodynamic-oriented approach to antifungal therapy than the use of traditional blood levels. Fluconazole is a broad spectrum, orally active triazole derivative developed by Pfizer. Skin pharmacokinetic results show that fluconazole reach the stratum corneum both through a direct diffusion and through sweat. Very high concentrations are obtained in the stratum corneum within hours after oral administration (23.4 pg/g), and fluconazole remains in the stratum comeum for a long time after seccesation of therapy. Recently very high concentrations (8.54 pg/g) have also been found in nails after weekly medication with 150 mg in the treatment of onychomycosis of the toenails. Itraconazole is an orally active triazole derivative developed by Janssen. It is lipophilic but found in lower concentrations in stratum comeum than both fluconazole and terbinafine. However, the levels in nails (0.93 pg/g) are comparable to terbinafine (0.39 @g/g) and it is also found there for several month after stop of therapy. Terbinafine, an orally active allylamine developed by Sandoz is orally active especially against dermatophytes. It is lipophilic and delivered to the stratum corneum through direct diffusion and in very high concentrations in sebum. It remain in the stratum comeum and especially in nails for a long time after stop of treatment.
SO98 Drug resistance and its clinical relevance D.W. Wamock. Mycology Laboratory
Service,
Bristol,
Reference UK
Laboratory,
Public
Health
Until the late 198Os, resistance to azole antifungals was an uncommon clinical problem and other factors were held to account for treatment failure or relapse. However, recent reports
R.A.J. Eady. St. John’s
Inst.
of Derm.
London,
UK
Epidermolysis bullosa (EB) comprises a number of genetically determined skin blistering disorders. Recently, there have been considerable advances in our understanding of the pathogenesis of the different forms of EB. This Session will cover some of the recently discovered genetic defects, especially as they relate to EB simplex and junctional EB and examine newer methods in treatment and diagnosis, including prenatal testing. On a more practical level, the organisation of a multi-disciplinary EB clinic and the nutritional requirements of EB patients will be discussed. The final presentation will explore the possibilities of developing new forms of treatment for EB, including gene therapy. I Si 00
Keratln gene mutations and epidermolysis bullosa
K.E. McKenna. Dept of Dermatology, Hospital
Group
Trust,
Craigavon,
Craigavon Area Northern Ireland
The cytoskeleton of epidermal cells consists of a network of keratin filaments. In the basal layer of the epidermis these filaments are composed of heterodimers of type I keratin K14 and type II keratin K5. Mutations of these keratins leads to aberrant keratin filament assembly and to basal cell cytolysis in Epidermolysis Bullosa Simplex (EBS) Experiments using transgenic mice have allowed prediction of clinical disease severity according to the site of mutation within the keratin protein structure. The Dowling-Meara and Koebner forms of EBS are characterized by generalised blistering. The former is more severe and electron-dense keratin aggregates are seen in the cell cytoplasm. Mutations in this
S26
Symposia
-
Epidetmolysis
form are clustered in the highly conserved ends of the central o-helical rod domains. In the Koebner form mutations tend to occur within the a-helical rod domains. In the milder, localised Weber-Cockayne form mutations are often found in non-helical regions. The identification of keratin gene mutations can now be applied to the prenatal diagnosis of EBS.
a dermatologist every three months should be performed for prevention of skin cancer. I S103 Nutritional requirements in epidermolysis
bullosa (EB) patients
Lesley Haynes. Great NHS
I Si 01
Recent advances in junctional epidermolysis bullosa
John A. M&ram. Thomas’s
Hospital,
St John’s London,
Institute UK
of Dermatology,
St
Junctional epidermolysis bullosa (JEB) is a clinically heterogeneous disorder, the pathogenesis of which involves mutations in the genes encoding a number of different structural macromolecules of the hemidesmosome-anchoring filament complex. The severe, lethal (Herlitz) form of JEB is caused by premature termination codon (PTC) mutations on both alleles of either the LAMA3, LAMB3 or LAMC2 genes which encode the CY~,83 or y2 polypeptide chains of laminin 5, respectively. Cases of nonlethal JEB, associated with chronic poorly healing trauma-induced erosions, may also arise due to laminin 5 mutations, usually involving a PTC on one allele, and a less disruptive mutation, such as a missense mutation, on the other allele. In addition, PTC mutations on both alleles of the 180~kDa bullous pemphigoid antigen gene, also known as type XVII collagen, (BPAG2/COL17Al) have been found in a subtype of nonlethal JEB known as generalized atrophic benign epidermolysis bullosa. Most recently, mutations in the (~6 and 84 integrin genes (ITGA6 and ITGB4) have been delineated in the variant of JEB associated with pyloric atresia. Knowledge of the molecular basis of JEB has important clinical implications for affected patients and their families. Determining specific gene abnormalities has lead to better genetic counselling, the development of DNA-based prenatal diagnosis, and a foundation for the planning newer forms of treatment, including somatic gene therapy. I S102 The organization of a multidisciplinary
Epidermolysis Bullosa clinic
Cl. Blanchet-Bardon.
Hdpital
Saint-Louis,
Paris,
France
The management of Epidermolysis Bullosa (EB), especially severe recessive dystrophic EB, requires a multidisciplinary staff. As soon as the baby is born correct diagnosis should be made by biopsy with electron microscopy and immunofluorescence. This biopsy will provide prognostic information leading in a case of severe recessive dystrophic EB to educate the parents to prevent further blistering, to establish adequate feeding and growth by the nutritionist and genetic counselling for the family. In early infancy, a multidisciplinary management has to be organized with the Dermatologist, Ophtalmologist, Handsurgeons, Stomatologist, Physiotherapist, Nutritionist, Gastroenterologist and Infectiologist, Nephrologist and Anesthesiologist. In addition this multidisciplinary approach includes social workers for social, school and work-integration. Later on in adulthood a special consultation and survey with
Bullosa
Trust,
London,
Ormond UK
Street Hospitalfor
Children
Two main factors potentially compromise nutritional status in EB:(a) the extent to which skin lesions, consequent losses of blood and serous fluid, and infections contribute to increased requirements and (b) the degree to which oral, oro-pharyngeal, oesophageal and gastro-intestinal complications limit intake. Malnutrition and growth failure should be avoidable (except in lethal junctional EB), with early dietary intervention (supplementation of energy, protein, iron, zinc, fibre and vitamins) and close monitoring (nutritional assessment, anthropometry, haematology and biochemistry). A multi-disciplinary approach is essential since factors such as poor skin care, gastro-oesophageal reflux, chronic constipation, anaemia etc. indirectly affect nutritional status. Many recessive dystrophic EB patients cannot maintain satisfactory progress without insertion of a ‘button’ gastrostomy. This type of intervention should be considered early. I S104 Prenatal diagnosis of epidermolysis bullosa R.A.J. Eady. St John’s Institute of Dermatology, UMDS, St Thomas’s
Hospital,
London,
UK
Fetal skin biopsy, initially performed under fetoscopic monitoring, and more recently using high resolution ultrasound guidance, has been the mainstay for the prenatal diagnosis (PND) of junctional EB (JEB) and dystrophic EB (DEB) over the past 17 years. However, following the recent discovery of the genetic causes of all the major forms of EB, DNA-based PND of JEB and DEB is now not only possible, but has been successfully used in the testing of a total of over 40 pregnancies in the few centres currently able to undertake this form of analysis. Chorion has identical DNA to the fetus, and chorionic villus sampling performed at 10-l 1 week’s gestation is an established method of obtaining an adequate amount of DNA for PND involving linkage analysis, mutation screening or direct sequencing. This approach can currently be used to search for mutations in any of the 6 genes causing JEB, or in the single collagen VII gene (COL7Al) underlying both dominant and recessive forms of DEB.
S105 1 The future of gene therapy for EB W.H.I. McLean. Epithelial Jefferson
Medical
College,
Genetics Group, Dept Dermatology, Philadelphia PA, USA
Despite a deluge of media attention, no case exists where gene therapy has completely cured a genetic disorder. Epidermolysis bullosa (EB) is a group of genodermatoses which are both clinically and genetically heterogeneous. Ten genes are now known to cause various forms of EB, facilitating the preven-