Adult mastocytosis is an incurable clonal disease associated with c-KIT mutations, mostly in exon 17 (D816V). In contrast, pediatric mastocytosis often spontaneously regresses and is considered a reactive disease. Previous studies on childhood mastocytosis assessed only a few patients and focused primarily on codon 816 mutations, with various results. In this study, we analyzed the entire c-KIT sequence from cutaneous biopsies of 50 children with mastocytosis (ages 0-16 years). A mutation of codon 816 (exon 17) was found in 42% of cases, and mutations outside exon 17 were observed in 44%. Unexpectedly, half of the mutations were located in the fifth Ig loop of c-KIT's extracellular domain, which is encoded by exons 8 and 9. All mutations identified in this study were somatic and caused a constitutive activation of c-KIT. There was no clear phenotype-genotype correlation, no clear relationship between the mutations and familial versus spontaneous disease, and no significant change in the relative expression of the c-KIT GNNK+ and GNNK isoforms. These findings strongly support the idea that, although pediatric mastocytosis can spontaneously regress, it is a clonal disease most commonly associated with activating mutations in c-KIT.

Imatinib is a promising candidate for the treatment of fibrotic diseases. This retrospective study evaluated the use of imatinib for the treatment of refractory sclerotic chronic graft-versus-host disease in 14 patients with different hematologic malignancies. Imatinib was started at a median of 44 months after transplantation (range, 16-119 months after transplantation) and was administered for a median of 5.9 months from time of initiation (range, 2.1-74 months from time of initiation). With a median overall follow-up of 11.6 months from time of initiation (range, 4.1-74 months from time of initiation) of imatinib, 4 patients (29%) had to stop imatinib because of drug intolerance. All other adverse reactions were of mild-tomoderate grade and could be managed symptomatically. Overall, 7 patients responded to imatinib (50%; 95% confidence interval, 24%-76%) with 4 patients improving their Rodman score more than or equal to 90%. In addition, imatinib therapy allowed for a significant reduction of corticosteroid dosage. Despite its limited size, this cohort suggests some beneficial activity of imatinib in sclerotic chronic graft-versus-host disease, warranting further prospective investigations. (Blood. 2009

Missense mutations affecting membrane-bound transcription factor protease site 2 (MBTPS2) have been associated with Ichthyosis Follicularis with Atrichia and Photophobia (IFAP) syndrome with or without BRESHECK syndrome, with keratosis follicularis spinulosa decalvans, and Olmsted syndrome. This metalloprotease activates, by intramembranous trimming in conjunction with the protease MBTPS1, regulatory factors involved in sterol control of transcription and in cellular stress response. In this study, 11 different MBTPS2 missense mutations detected in patients from 13 unrelated families were correlated with the clinical phenotype, with their effect on cellular growth in media without lipids, and their potential role for sterol control of transcription. Seven variants were novel [c.774C>G (p.I258M); c.758G>C (p.G253A); c.686T>C (p.F229S); c.1427T>C (p.L476S); c.1430A>T (p.D477V); c.1499G>A (p.G500D); c.1538T>C (p.L513P)], four had previously been reported in unrelated sibships [c.261G>A (p.M87I); c.1286G>A (p.R429H); c.1424T>C (p.F475S); c.1523A>G (p.N508S)]. In the enzyme, the mutations cluster in transmembrane domains. Amino-acid exchanges near the active site are more detrimental to functionality of the enzyme and, clinically, associated with more severe phenotypes. In male patients, a genotype-phenotype correlation begins to emerge, linking the site of the mutation in MBTPS2 with the clinical outcome described as IFAP syndrome with or without BRESHECK syndrome, keratosis follicularis spinulosa decalvans, X-linked, Olmsted syndrome, or possibly further X-linked traits with an oculocutaneous component.

To determine the frequency of skin disorders encountered in a paediatric emergency care unit and to evaluate the benefits of advice from a dermatologist, we prospectively recorded data of children admitted with skin disorders to the emergency care unit during a 5-month period. Diagnostic agreement between paediatricians and dermatologists evaluating the patients separately was assessed. Three hundred and ninety-five children (median age 3 years; interquartile 1-6) were included. Skin disorders represented 4% of all paediatric emergency care unit visits. Visits were considered as appropriate in 19-30% of cases according to different criteria. Six diseases accounted for 57% of cases: viral exanthema, urticaria, atopic dermatitis, varicella, diaper dermatitis and herpetic gingivostomatitis. The dermatologist modified the diagnosis in 42% of cases and the treatment in 30%. Greater emphasis on teaching the skin disorders encountered in this setting and efforts to provide easy access to advice from dermatologist would improve the quality of care.