Focal dermal hypoplasia (FDH) is an X-linked dominant multisystem birth defect affecting tissues of ectodermal and mesodermal origin. Using a stepwise approach of (i) genetic mapping of FDH, (ii) high-resolution comparative genome hybridization to seek deletions in candidate chromosome areas and (iii) point mutation analysis in candidate genes, we identified PORCN, encoding a putative O-acyltransferase and potentially crucial for cellular export of Wnt signaling proteins, as the gene mutated in FDH. The findings implicate FDH as a developmental disorder caused by a deficiency in PORCN.

The autosomal recessive disorder lipoid proteinosis results from mutations in extracellular matrix protein 1 (ECM1), a glycoprotein expressed in several tissues (including skin) and composed of two alternatively spliced isoforms, ECM1a and ECM1b, the latter lacking exon 7 of this 10-exon gene (ECM1). To date, mutations that either affect ECM1a alone or perturb both ECM1 transcripts have been demonstrated in six cases. However, lipoid proteinosis is clinically heterogeneous with affected individuals displaying differing degrees of skin scarring and infiltration, variable signs of hoarseness and respiratory distress, and in some cases neurological abnormalities such as temporal lobe epilepsy. In this study, we sequenced ECM1 in 10 further unrelated patients with lipoid proteinosis to extend genotype-phenotype correlation and to add to the mutation database. We identified seven new homozygous nonsense or frameshift mutations: R53X (exon 3); 243delG (exon 4); 507delT (exon 6); 735delTG (exon 7); 785delA (exon 7); 892delC (exon 7) and 1190insC (exon 8), as well as two new compound heterozygous mutations: W160X/F167I (exon 6) and 542insAA/R243X (exons 6/7), none of which were found in controls. The mutation 507delT occurred in two unrelated subjects on different ECM1 haplotypes and may therefore represent a recurrent mutation in lipoid proteinosis. Taken with the previously documented mutations in ECM1, this study supports the view that exons 6 and 7 are the most common sites for ECM1 mutations in lipoid proteinosis. Clinically, it appears that mutations outside exon 7 are usually associated with a slightly more severe mucocutaneous lipoid proteinosis phenotype, but neurological features do not show any specific genotype-phenotype correlation.

Objective. Juvenile localized scleroderma is a chronic progressive fibrotic disorder of the skin that causes permanent disability and aesthetic damage. This study was undertaken to assess the safety and efficacy of methotrexate (MTX) in the treatment of juvenile localized scleroderma.Methods. In this double-blind study, patients with active juvenile localized scleroderma were randomized (2:1) to receive oral MTX (15 mg/m 2 , maximum 20 mg) or placebo once weekly, for 12 months or until treatment failure. Both groups received oral prednisone (1 mg/kg/ day, maximum 50 mg) for the first 3 months. A target lesion was evaluated clinically, with infrared thermography and using a computerized scoring system with skin score rate (SSR) evaluation. Response to treatment was defined as the absence of new lesions, SSR <1, and a decrease in lesion temperature of at least 10% compared to baseline. Treatment failure was defined as the occurrence of new lesions, SSR >1, or increased lesion temperature. All analyses were done on the intent-totreat population.Results. Of the 85 patients screened, 70 (ages 6-17 years) were randomized (46 to the MTX group, 24 to the placebo group). The mean disease duration was 2.3 years. After an initial response in all patients, disease relapsed in 15 MTX-treated patients (32.6%) and 17 placebo-treated patients (70.8%) (P < 0.005). New lesions appeared in 3 MTX-treated patients (6.5%) versus 4 placebo-treated patients (16.7%). The mean SSR decreased from 1 to 0.79 in the MTX group and increased from 1 to 1.1 in the placebo group, and the mean target lesion temperature decreased by 44.4% in the MTX group versus 12.1% in the placebo group. Twenty-six patients in the MTX group (56.5%) and 11 patients in the placebo group (45.8%) developed mild side effects related to treatment. None of the side effects were severe enough to necessitate treatment discontinuation.Conclusion. Our findings indicate that MTX is efficacious in the treatment of juvenile localized scleroderma and is well tolerated.

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