ABSTRACT
Infantile myofibromatosis is a rare genetic disorder characterized by the development of benign tumors in the skin, muscle, bone, and viscera. The molecular pathogenesis is still incompletely known. An autosomal dominant form had been reported as causally related with mutations in the gene for platelet-derived growth factor receptor beta (PDGFRB). We report here two siblings with infantile myofibromatosis and with a PDGFRB mutation identified by exome sequence analysis. However, the unaffected mother also had the same PDGFRB mutation. We showed that both children had also inherited from their healthy father a heterozygous mutation in the gene for receptor protein tyrosine phosphatase gamma (PTPRG), an enzyme known to dephosphorylate PDGFRB. We suggest that in this family, the additional mutation in PTPRG may explain the full phenotypic penetrance in the siblings affected, in comparison with the unaffected mother.
Subject(s)
Genes, Modifier , Mutation , Myofibromatosis/congenital , Receptor, Platelet-Derived Growth Factor beta/genetics , Receptor-Like Protein Tyrosine Phosphatases, Class 5/genetics , Adult , Base Sequence , Child , Exome , Female , Gene Expression Regulation , Genotype , Heterozygote , Homozygote , Humans , Male , Molecular Sequence Data , Myofibromatosis/genetics , Myofibromatosis/pathology , Pedigree , Penetrance , Phenotype , SiblingsABSTRACT
BACKGROUND: Chromomycosis is a widespread subcutaneous fungal infection seen essentially in tropical and subtropical regions and transmitted via skin injury caused by the prickles of plants or infected wood splinters. It is prevalent throughout the West Indies including Guadeloupe, where its incidence is not well known. PATIENTS AND METHODS: This retrospective and descriptive study concerns five histologically established cases of chromomycosis in Guadeloupe between 1995 and 2005. The five patients were diagnosed and treated at Pointe-à-Pitre University Teaching Hospital. RESULTS: The study concerned four male patients and one female patient with an average age of 78 years; four were from the Basse-Terre district and one was from the Grande-Terre district. The most frequent clinical aspect was nodular or verrucous. The most common initial topography was the upper limbs. Fonsecaea pedrosoi was the only species identified. Diagnosis was confirmed by histopathology, which in all cases revealed sclerotic cells. Three patients underwent surgical treatment and two received medical treatment; only two patients were cured by 2005. DISCUSSION: Our study confirms the presence of a source of chromomycosis in Guadeloupe, where Fonsecaea pedrosoi is clearly the best adapted species. It also highlights the difficulties of therapeutic care in tropical areas.