[Hydroa vacciniforme-like cutaneous T cell lymphoma: a case report and literature review].

OBJECTIVE: To study the clinical features, diagnosis and therapy of hydroa vacciniforme-like cutaneous T cell lymphoma. METHODS: The clinical presentations and the findings of laboratory examinations and skin biopsy of affected tissue in a child with hydroa vacciniforme-like cutaneous T cell lymphoma were retrospectively reviewed. RESULTS: The child manifested as rash, fever and lymph node intumesce. Rash was pantomorphia, including edematous erythema, vesicles, crusts, necrosis and depressed scar, and it was mild in winter and severe in summer, mainly involving in the face and extremities. Epstein-Barre virus (EBV)-IgM was positive. Histopathological findings revealed focal lymphocyte invasion in subcutaneous panniculus adiposus, mainly surrounding the blood vessels. Immunohistochemistry showed CD3 (+), CD43 (+), CD20 (-), pax-5 (-), TIA (+), CD5 (+), CD8 (+), Granmye (+) and CD4 (-). The clinical symptoms were improved after glucocorticoid treatment in this child. CONCLUSIONS: Hydroa vacciniforme-like cutaneous T cell lymphoma has special clinical manifestations. This disorder may be definitely diagnosed by skin biopsy of affected tissue and immunohistochemistry assay. Glucocorticoid treatment is effective. EBV infection may be related to the development of this disorder.

[Effect of a novel splicing mutation (IVS2-2A-->C) of SEDL gene on RNA processing].

X-linked spondyloepiphyseal dysplasia tarda (SEDL) is a rare osteochondrodysplasia caused by the mutation of SEDL gene, which mainly involves vertebral bodies and hips. To explore the effect of the novel splicing mutation (IVS2 -2A-->C) of SEDL gene on mRNA processing in a large Chinese family with X-linked spondyloepiphyseal dysplasia tarda and to elucidate the molecular base of SEDL, total RNA was isolated from EDTA blood samples of patients and controls. RT-PCR was performed on total RNA. cDNA was analyzed by bi-directionally direct sequencing of PCR products and Polyacrylamide gel electrophoresis (PAGE). Sequencing analysis revealed that there were two kinds of cDNA in patients. One is that exon 2 directly spliced exon 4, that is, exon 3 absence from the mature mRNA; and the other is that exon 1 directly spliced exon 4, meaning both exon 2 and 3 being spliced out completely. Meanwhile one kind of cDNA that exon 1 directly spliced exon 3 was found in normal controls. By PAGE, RT-PCR amplified products, 679bp and 537bp, were detected in normal controls, while 567bp and 425bp fragments were found in affected individuals. Our data show that the mutation of the splice-acceptor site in intron 2 causes exon 3 entirely exclusion from the mature RNA transcripts in affected individuals. As the translation start site of the SEDL gene locates on exon 3, the splicing defect causes affected individuals failure to produce sedlin, which elucidates the causative role of SEDL gene in the pathogenesis of SEDL. The absence of exon 2 indicates that there is alternative splicing in SEDL gene. The alternative splicing was also found in normal controls, which demonstrated that the alternative splicing might not be related to the phenotype of SEDL. Because the alternative splicing of exon 2 occurred in the 5'UTR, it is not clear whether it affects the gene expression.

[Identification of a novel mutation IVS2-2A-->C of SEDL gene in a Chinese family with X-linked spondyloepiphyseal dysplasia tarda].

OBJECTIVE: To identify the mutation of spondyloepiphyseal dysplasia tarda (SEDL) gene in a large Chinese family with X-linked spondyloepiphyseal dysplasia tarda and to make a discussion on the pathogenesis of SEDL at the molecular level. METHODS: In two patients, four exons comprising the SEDL open reading frame as well as their exon/intron boundaries were analyzed by bi-directional direct sequencing of PCR products. The sequencing results were compared against the normal sequences in GenBank to find the mutation. Then the mutation was identified in other members of the family. RESULTS: A nucleotide substitution of the splice acceptor in SEDL intron 2, IVS2 -2A-->C,was detected in two affected individuals (IV(15) V(3)) in the Chinese family with SEDL, but no sequence change occurring on exons 3-6 was detected. The transversion was also identified in four heterozygous carriers. The mutation was not found in two unaffected male individuals and fifteen normal controls. Furthermore, four potential carriers were identified in the family. CONCLUSION: The mutation IVS2 -2A-->C of SEDL gene was firstly determined in the world. The change of the splice acceptor in SEDL intron 2 may cause skipping of exon 3 which is responsible for the disease. Molecular diagnosis can be made by detecting the mutation.

[Gene diagnosis of X-linked spondyloepiphyseal dysplasia tarda by linkage analysis and DNA sequencing].

OBJECTIVE: X linked spondyloepiphyseal dysplasia tarda (SEDL) is heritable osteochondrondysplasia characterized in affected males by disproportional short stature with short neck and trunk resulting from a growth defect of the vertebral bodies, accompanied by barrel chest and degenerative osteoarthropathy of hip joints. This progressive skeletal dysplasia is caused by the SEDL gene located approximately 100 kb centromeric of DXS16 at Xp22. The disorder usually manifests in late childhood without systemic complications, and generally female carriers of SEDL are asymptomatic. So the diagnosis of potential carriers and presymptomatic patients is almost impossible. This study aimed to establish methods of gene diagnosis for finding out potential carriers and presymptomatic patients. METHODS: The blood samples were collected from 21 individuals in a large Chinese pedigree with SEDL. Microsatellite marker DXS16 was selected for linkage analysis. In order to confirm the allele of DXS16 linked to the pathogenic SEDL gene, polymerase chain reaction (PCR) and polyacrylamide gel electrophoresis (PAGE) were used to examine the variability of the lengths of DXS16, and linkage analysis was performed for the diagnosis of potential carriers and presymptomatic patients. Then the pathogenic mutation of the SEDL gene in the family was identified by bi-directionally direct sequencing of PCR products amplified for each of the four coding exons as well as their exon/intron boundaries. The potential carriers and presymptomatic patients were also diagnosed in this way. RESULTS: Six young individuals (IV(14), IV(19), IV(21), IV(23), V(4), V(7))who wanted to know whether they were carriers or presymptomatic patients were diagnosed by linkage analysis. Four females of them (IV(14), IV(19), IV(21), V(7)) were determined being carriers because they carry the allele of DXS16 which links the pathogenic SEDL gene, and the other two (IV(23), V(4)) being normal individuals for their alleles of DXS16 linked with wild SEDL gene. DNA sequencing identified that the pathogenic mutation of SEDL gene in the family, which was a nucleotide substitution of the splice-acceptor site in intron 2, IVS2 -2 A-->C. This is a novel mutation in the SEDL gene. Four female individuals (IV(14), IV(19), IV(21), V(7)) carried the mutation; individuals IV(23) and V(4) carried the wild SEDL gene. The results of diagnosis of linkage analysis coincide completely with that of DNA sequencing. CONCLUSION: Linkage analysis is a simple, rapid and inexpensive gene diagnosis method for SEDL and its accuracy was the same as DNA sequencing. Each of linkage analysis and DNA sequencing can be used to diagnose SEDL, which is very helpful for finding potential carriers and presymptomatic patients.