Junctional epidermolysis bullosa (JEB) is a group of heritable blistering diseases in which tissue separation occurs within the lamina lucida of the cutaneous basement membrane zone. Clinically, two broad subcategories have been recognized: The Herlitz variant (H-JEB; OMIM 226700) is characterized by early demise of the affected individuals, usually within the first year of life, while non-Herlitz (nH-JEB; OMIM 226650) patients show a milder phenotype with life-long blistering, yet with normal lifespan. In this study, we have examined a cohort of 27 families, 15 with Herlitz and 12 with non-Herlitz JEB, for mutations in the candidate genes, LAMA3, LAMB3, and LAMC2, encoding the subunit polypeptides of laminin 5. The mutation detection strategy consisted of PCR amplification of all exons in these genes, followed by heteroduplex scanning and nucleotide sequencing. We were able to identify pathogenic mutations in both alleles of each proband, the majority of the mutations being in the LAMB3 gene. Examination of the mutation database revealed that most cases with Herlitz JEB harbored premature termination codon (PTC) mutations in both alleles. In non-Herlitz cases, the PTC mutation was frequently associated with a missense mutation or a putative splicing mutation in trans. In three cases with putative splicing mutations, RT-PCR analysis revealed a repertoire of splice variants in-frame, predicting the synthesis of either shortened or lengthened, yet partly functional, polypeptides. These observations would explain the relatively mild phenotype in cases with splicing mutations. Collectively, these findings, together with the global laminin 5 mutation database, contribute to our understanding of the genotype/phenotype correlations explaining the Herlitz vs non-Herlitz phenotypes.

Epidermolysis bullosa with pyloric atresia (EB-PA: OMIM 226730), also known as Carmi syndrome, is a rare autosomal recessive genodermatosis that manifests with neonatal mucocutaneous fragility associated with congenital pyloric atresia. The disease is frequently lethal within the first year, but nonlethal cases have been reported. Mutations in the genes encoding subunit polypeptides of the ␣6␤4 integrin (ITGA6 and ITGB4) have been demonstrated in EB-PA patients. To extend the repertoire of mutations and to identify genotype-phenotype correlations, we examined seven new EB-PA families, four with lethal and three with nonlethal disease variants. DNA from patients was screened for mutations using heteroduplex analysis followed by nucleotide sequencing of PCR products spanning all ␤4 integrincoding sequences. Mutation analysis disclosed 12 distinct mutations, 11 of them novel. Four mutations predicted a premature termination codon as a result of nonsense mutations or small out-of-frame insertions or deletions, whereas seven were missense mutations. This brings the total number of distinct ITGB4 mutations to 33. The mutation database indicates that premature termination codons are associated predominantly with the lethal EB-PA variants, whereas missense mutations are more prevalent in nonlethal forms. However, the consequences of the missense mutations are position dependent, and substitutions of highly conserved amino acids may have lethal consequences. In general, indirect immunofluorescence studies of affected skin revealed negative staining for ␤4 integrin in lethal cases and positive, but attenuated, staining in nonlethal cases and correlated with clinical phenotype. The data on specific mutations in EB-PA patients allows prenatal testing and preimplantation genetic diagnosis in families at risk. Abbreviations EB-PA, epidermolysis bullosa with pyloric atresia BMZ, basement membrane zone CSGE, conformation-sensitive gel electrophoresis PTC, premature termination codon TEM, transmission electron microscopy ITGB4, ␤4 integrin gene Epidermolysis bullosa (EB) is a group of genodermatoses manifesting with blistering and erosions of the skin and mucous membranes as a result of mechanical trauma (1, 2). The clinical severity of EB is highly variable. In the mildest cases, blistering occurs primarily on the hands and feet with relatively little morbidity, whereas, in the most severe cases, the disease can be lethal perinatally or during the early postnatal period. Traditionally, EB has been divided into three broad categories based on clinical findings and ultrastructural demonstrations of

Background: Many types of fermented food are consumed in Japan. Although some are produced by plant-origin lactic-acid bacteria (LAB) fermentation, the physiological functions of such bacteria remain unclear. We therefore isolated LAB of plant origin from Kyoto pickles and determined the immunological activity of heat-killed preparations of plant-origin LAB. Methods: The Lactobacillus pentosus strain S-PT84 was selected from among 16 LAB of plant origin as the strongest interleukin (IL)-12-inducing strain. IL-12- and IL-10-inducing activities were determined with macrophages from BALB/c mice. The in vivo immunomodulating effect of S-PT84was determined with BALB/c mice fed S-PT84. The antiallergic activity of S-PT84 was examined in ovalbumin (OVA)/alum-administered BALB/c mice. Results: The L. pentosus strain S-PT84 induced production of both IL-12 and IL-10 in vitro. S-PT84 enhanced splenic natural-killer activity and modulated the T helper (Th) type 1/type 2 balance toward a Th1-dominant state. In the OVA-induced allergy model, orally administered S-PT84 lowered serum IgE levels and suppressed active cutaneous anaphylaxis reaction and splenic IL-4 production. IL-10 production from splenocytes of OVA-immunized mice was upregulated by feeding S-PT84. Conclusions: Despite heat-killing, S-PT84 exhibited antiallergic effects by modulating the Th1/Th2 balance and inducing regulatory T cells. The L. pentosus strain S-PT84, which is of plant origin and isolated from a traditional Japanese food, is expected to be useful for treatment of many immune diseases including allergies, tumors, infectious diseases and auto-immune diseases.

Pseudoxanthoma elasticum (PXE) is a systemic heritable disorder affecting the elastic structures in the skin, eyes, and cardiovascular system, with considerable morbidity and mortality. Recently, mutations in the ABCC6 gene (also referred to as "MRP6" or "eMOAT") encoding multidrug-resistance protein 6 (MRP6), a putative transmembrane ABC transporter protein of unknown function, have been disclosed. Most of the genetic lesions delineated thus far consist of single-base-pair substitutions resulting in nonsense, missense, or splice-site mutations. In this study, we examined four multiplex families with PXE inherited in an autosomal recessive pattern. In each family, the proband was a compound heterozygote for a single-base-pair-substitution mutation and a novel, approximately 16.5-kb deletion mutation spanning the site of the single-base-pair substitution in trans. The deletion mutation was shown to extend from intron 22 to intron 29, resulting in out-of-frame deletion of 1,213 nucleotides from the corresponding mRNA and causing elimination of 505 amino acids from the MRP6 polypeptide. The deletion breakpoints were precisely the same in all four families, which were of different ethnic backgrounds, and haplotype analysis by 13 microsatellite markers suggested that the deletion had occurred independently. Deletion breakpoints within introns 22 and 29 were embedded within AluSx repeat sequences, specifically in a 16-bp segment of DNA, suggesting Alu-mediated homologous recombination as a mechanism.

The ABCC6 gene encodes MRP6, a member of the multidrug resistance-associated protein (MRP) family. Interest in ABCC6/MRP6 derives, in part, from the fact that mutations in this gene/protein system have been identified in families with pseudoxanthoma elasticum (PXE). Early studies indicated that ABCC6 is expressed primarily in the liver and to a lesser extent in the kidney, but more recently a widespread distribution has been suggested. To explore the tissue-specific expression of ABCC6, we first examined various mouse tissues by RT-PCR. The results indicated high levels of mRNA in the liver, whereas low level of expression was noted in the kidney and small intestine. To explore other tissues in which initial RT-PCR was essentially negative, a second-round nested PCR was performed, which revealed expression also in the brain, tongue, stomach, and eye. Unexpectedly, however, distinct PCR products of smaller molecular weight were noted in these tissues. Subcloning and sequencing of these PCR products indicated that they reflected aberrant splicing in the 3' end of the ABCC6 mRNA, resulting in each case in a premature termination codon. Similar results were noted with RT-PCR analysis using RNA isolated from cultured human epidermal keratinocytes and dermal fibroblasts. Collectively, our results confirm high level of expression of ABCC6 in the liver and the kidney, whereas very low level of expression in a variety of other tissues was noted. The results have implications for mutation detection strategies in PXE by RT-PCR, and they further support the notion that PXE is a primary metabolic disorder.

Pseudoxanthoma elasticum (PXE), a heritable disorder affecting the skin, eyes, and the cardiovascular system, has recently been linked to mutations in the ABCC6 gene on chromosome 16p13.1. The original mutation detection strategy employed by us consisted of the amplification of each exon of the ABCC6 gene with primer pairs placed on the flanking introns, followed by heteroduplex scanning and direct nucleotide sequencing. However, this approach suggested the presence of multiple copies of the 5'-region of the gene when total genomic DNA was used as a template. In this study, we have identified two pseudogenes containing sequences highly homologous to the 5'-end of ABCC6. First, by the use of allele-specific polymerase chain reaction (PCR), two bacterial artificial chromosome (BAC) clones containing a putative pseudogene of ABCC6, designated as ABCC6-psi 1, were isolated from the human BAC library. Sequence analysis of ABCC6-psi 1 revealed it to be a truncated copy of ABCC6, which contains the upstream region and exon 1 through intron 9 of the gene. Secondly, a homology search of a high-throughput sequence database revealed the presence of another truncated copy of ABCC6, which was designated as ABCC6-psi 2, and which was shown to harbor upstream sequences and a segment spanning exon 1 through intron 4 of ABCC6. In addition to several nucleotide differences in the flanking introns and the upstream region, both pseudogenes contain several nucleotide changes in the exonic sequences, including stop codon mutations, which complicate mutation analysis in patients with PXE. Nucleotide differences in flanking introns between these two pseudogenes and ABCC6 allowed us to design allele-specific primers that eliminated the amplification of both pseudogene sequences by PCR and provided reliable amplification of ABCC6-specific sequences only. The use of allele-specific PCR has revealed, thus far, two novel 5'-end PXE mutations, 179del9 and T364R in exons 2 and 9, respectively, and several polymorphisms within the upstream region and exons 1-9 of ABCC6. These strategies facilitate comprehensive analysis of ABCC6 for mutations in PXE.

Epidermolysis bullosa (EB) is a group of inherited disorders characterized by increased skin fragility, resulting in blisters and erosions after minor trauma. Mutations in 10 structural genes expressed in the cutaneous basement membrane zone have been reported. The DebRA Molecular Diagnostics Laboratory at Jefferson Medical College has performed 144 DNA-based prenatal diagnoses since 1993 in families at risk for recurrence of the most severe forms of EB, including the recessive dystrophic EB (RDEB), junctional EB (JEB), EB with pyloric atresia (EB-PA), and EB simplex (EBS). A mutation-detection strategy using either conformation-sensitive gel electrophoresis (CSGE) or denaturing high-performance liquid chromatography (dHPLC) scanning analysis, followed by nucleotide sequencing, was applied to most cases with DEB and to all JEB, EB-PA, and EBS families. For some RDEB families, linkage analysis was performed, either alone when the inheritance pattern was clear or in combination with one mutation. Among the 144 prenatal diagnoses, 63 were for RDEB, 69 for JEB, 6 for EB-PA, and 6 for EBS. Twenty-eight normal, 73 heterozygous carrier, and 28 affected RDEB, JEB, and EB-PA pregnancies were reported in these recessively inherited diseases. Two affected and four normal pregnancies were predicted in dominantly inherited EBS. Among the 144 pregnancies, 9 were terminated without confirmation, 13 cases were lost to follow-up, and 6 pregnancies are ongoing. There were 6 families with inconclusive results due either to recombination events between flanking markers, absence of informative markers for one allele, or lack of sample from the previously affected child. There were three discordant results, one that was explained by maternal contamination of the chorionic villus sample and two that were unresolved. Overall, the availability, relative ease, and over 98% success rate make molecular DNA-based prenatal diagnosis a viable option for EB families at risk.

The Papillon-Lefèvre syndrome, inherited in an autosomal recessive pattern, manifests with palmoplantar keratoderma and early, destructive periodontitis. Recently, mutations in the gene encoding cathepsin C have been disclosed in a limited number of families with Papillon-Lefèvre syndrome. We have examined two multiplex families with Papillon-Lefèvre syndrome, and evaluated the gene encoding cathepsin C for mutations. The mutation detection strategy consisted of polymerase chain reaction amplification of all seven exons and flanking intronic sequences, followed by direct nucleotide sequencing. This strategy identified two missense mutations, W39S and G301S, affecting highly conserved amino acid residues within the cathepsin C polypeptide. The affected individuals were homozygotes whereas heterozygous carriers of the mutations were clinically unaffected, confirming the recessive nature of the mutations. Addition of these cathepsin C gene mutations into the expanding Papillon-Lefèvre syndrome mutation database allows further development of genotype/phenotype correlations towards understanding this severe genodermatosis.