A novel mutation links to von Hippel-Lindau syndrome in a Chinese family with hemangioblastoma.

Hemangioblastoma of the central nervous system occurs as sporadic tumors or as a part of von Hippel-Lindau (VHL) disease, an autosomal dominant hereditary tumor syndrome caused by a germline mutation in the VHL tumor suppressor gene. We screened a Chinese family with VHL for mutations in the VHL gene and evaluated a genetic test for diagnosing VHL disease and clinical screening of family members. DNA extracted from the peripheral blood of all live members and from tissue of deceased family members with VHL disease was amplified by polymerase chain reaction to 3 VHL gene exons. Mutations in the amplification products were compared against the Human Gene Mutation Database. The involvement of multiple organs among the kindred with VHL disease was confirmed by medical history and radiography. Of the 12 members of the 4-generation family, 5 were diagnosed with VHL disease. Patient age at the initial diagnosis was 26-36 years (mean = 31 years). The mean time was 15 (11-19 months) from symptom appearance to the first patient visit to the hospital. Sequence analysis revealed that the frameshift mutation 327del C (p.Gly39Alafs*26) in exon 1 affected all family members, but not the healthy individuals or 16 unrelated controls. Members without gene mutation showed no clinical manifestation of VHL disease. We detected a conserved novel frameshift mutation in the VHL gene of the family members that contributes to VHL. DNA analysis of VHL is advantageous for VHL diagnosis. We developed a quick and reliable method for VHL diagnosis.

Defects in mTR stability and telomerase activity produced by the Dkc1 A353V mutation in dyskeratosis congenita are rescued by a peptide from the dyskerin TruB domain.

BACKGROUND: The predominant X-linked form of dyskeratosis congenita results from mutations in dyskerin, a protein required for ribosomal RNA modification that is also a component of the telomerase complex. We have previously found that expression of an internal fragment of dyskerin (GSE24.2) rescues telomerase activity in X-linked dyskeratosis congenita (X-DC) patient cells. MATERIALS AND METHODS: Here, we have generated F9 mouse cell lines expressing the most frequent mutation found in X-DC patients, A353V and study the effect of expressing the GSE24.2 cDNA or GSE24.2 peptide on telomerase activity by TRAP assay, and mTERT and mTR expression by Q-PCR. Point mutation in GSE24.2 residues were generated by site-directed mutagenesis. RESULTS: Expression of GSE24.2 increases mTR and to a lesser extent mTERT RNA levels, and leads to recovery of telomerase activity. Point mutations in GSE24.2 residues known to be highly conserved and crucial for the pseudouridine-synthase activity of dyskerin abolished the effect of the peptide. Recovery of telomerase activity and increase in mTERT levels were found when the GSE24.2 peptide purified from bacteria was introduced into the cells. Moreover, mTR stability was also rescued by transfection of the peptide GSE24.2. DISCUSSION: These data indicate that supplying GSE24.2, either from a cDNA vector, or as a peptide, can reduces the pathogenic effects of Dkc1 mutations and could form the basis of a novel therapeutic approach.

Common denominators in the etiology and pathology of visceral lesions of cystic fibrosis and Keshan disease.

The common denominator of a unique disseminated multi-focal miliary myocardial hyaline necrosis and fibrosis in Keshan disease (KSD) and cystic fibrosis (CF) and a commonality of the affected age groups of fetuses and preschool children led to the review of existing KSD autopsy material to search for pancreatic and hepatic lesions considered pathognomonic for CF. Pancreatic lesions considered pathognomonic for CF were found in 595, or 35% of 1700 documented cases of KSD. The pancreatic lesions were limited to tissues of fetuses and preschool children. Adults dying of KSD had diagnostic lesions limited to the cardiovascular system, liver, and skeletal muscle. Varying degrees of focal biliary cirrhosis were identified in 850, or 50% of the KSD autopsies, and 85, or 5% developed severe lobular cirrhosis. The common denominator in CF and KSD appears to be a primary or induced secondary selenium deficiency in age-susceptible humans, prenatally at or around 22 wk of fetal life, during early postnatal life, or during the rapid-growth preschool years. The basic difference between the natural history of CF and KSD is that the selenium deficiency is totally environmental in KSD and appears to be the result of a maternal malabsorptive syndrome or an abnormality of selenium transfer in CF.