A novel mutation in LMX1B gene causes nail-patella syndrome in a large Chinese family.

We conducted clinical and genetic studies in a large Chinese family with nail-patella syndrome (NPS) involving multi-organ (such as limb, renal and eye) and investigated the functional consequences of a novel LMX1B mutation identified in the family. Twenty individuals at risk for inheriting NPS in the Chinese family participated in the study and a physical examination was performed and blood was drawn for DNA extraction. Linkage analysis and mutation screening of LMX1B gene were performed and the functional study in vitro for the mutation was conducted by luciferase assay. The disease phenotype of this family was linked to D9S290 with LOD Score=5.8 at theta=0; a novel mutation 742 A>G (R248G) within the homeodomain was found in a conserved site and co-segregated with the disease phenotype of the family. The functional study in vitro by luciferase assay indicated that the R248G mutation within the binding domain of the gene affected the transactivation. This is the first report that a mutation in the LMX1B gene causes NPS in a Chinese population, which will expand the spectrum of mutations in the LMX1B gene and provide insight into the underlining pathology of NPS.

A genome-wide scan maps a novel autosomal dominant juvenile-onset open-angle glaucoma locus to 2p15-16.

PURPOSE: To study the clinical features and to perform genetic linkage study in two large Chinese families with autosomal dominant juvenile-onset primary open-angle glaucoma (POAG). METHODS: Eighteen members of one Chinese family and 25 members of a second Chinese family with juvenile-onset primary open-angle glaucoma (POAG) were investigated. Thirteen members in one family and 14 members in the second family were diagnosed with juvenile-onset POAG. A genome-wide linkage scan was performed on one family using 411 short tandem repeat (STR) markers. Subsequent fine mapping was performed in the two study families using a modified fluorescent labeled M13 primer method. RESULTS: A whole genome-wide scan in one family showed linkage to chromosome 2p15-p16 with a two-point maximum LOD score of 5.01 at theta=0 between the disease phenotype and STR marker D2S337. The second family was also mapped to the same locus with a two-point maximum LOD score of 6.30 at theta=0 for D2S378. Haplotype analysis in these two families demonstrated that they shared the same disease haplotype, suggesting they have inherited the mutation from a common founder. The maximum LOD scores were 8.93 at theta=0 for D2S378 and 9.9 at theta=0 for D2S337 when the two families were combined for analysis. The disease interval for these two families was localized to 9.2 cM or 13.3 Mb between D2S123 and D2S2397. There are 42 known genes/transcripts within the interval. Five of these genes were sequenced, and no disease-causing mutation was identified in either family. CONCLUSIONS: This novel juvenile-onset POAG locus on chromosome 2p15-16 is overlapped by the Glaucoma 1, open angle, H (GLC1H) locus for adult-onset POAG. Eventual identification of the disease-causing gene will provide insights into the pathogenesis of POAG.

[Determination of tin in canned foods with oscillographic polarography].

OBJECTIVE: To develop an oscillographic polarography method for determining the concentration of tin in canned foods. METHODS: Because the sensitive polarography wave of tin can be obtained in the system of H2SO4-KI-VitC- NH4VO3, the tin content of several canned foods was analyzed. RESULTS: The detection limit was 0.12 microgram/L. The calibration graph of Sn was linear from 0 to 2.0 micrograms/ml, and the relative standard deviation ranged from 4.22% to 8.33%. The recoveries were 94.7%-112.0%. The samples were analyzed by the proposed method and standard method. The results of the two methods agreed well. CONCLUSION: This method is simple, quick and almost free from interference, and it is available for use in analysis of the canned sample.