Identification of compound heterozygous mutations in the ITGA2B gene in a Chinese patient with Glanzmann thrombasthenia.

BACKGROUND: Glanzmann thrombasthenia (GT) is an autosomal recessive bleeding disorder characterized by the tendency to hemorrhage and the inability of platelets to aggregate in response to agonists. GT is caused by a defect of the platelet glycoprotein IIb/IIIa complex. The objective of this study was to describe the clinical features and the genetic cause of GT in a 6-year-old girl from south China. METHODS: A three-generation family was studied. The proband patient aged 6 years and her parents undertook examinations of platelet counts, blood film, bleeding time, platelet aggregation, and flow cytometry. All coding exons of the ITGA2B and ITGB3 genes were amplified by polymerase chain reaction (PCR), and direct sequencing was performed for mutational screening on the patient and normal controls consisted of 52 healthy blood donors. Reverse transcription PCR was conducted to test for exon skipping. RESULTS: The proposita patient showed dispersing platelets, prolonged bleeding time, and severely reduced platelet aggregation in response to the physiological agonists adenosine diphosphate (ADP), epinephrine, collagen, and ristocetin. Flow cytometric measurements showed that the contents of alphaIIb and beta3 were significantly decreased. Sequencing results demonstrated two different types of heterozygous mutations existed in the alphaIIb gene (c.2930delG and IVS15-1delG). The compound mutations were also confirmed in the patient's mother and father separately. CONCLUSIONS: The alphaIIbbeta3 deficiency of the proband was caused by two compound ITGA2B mutations, which were first reported in Chinese GT patients. The IVS15-1delG was first confirmed to cause an exon skipping.

[Detection of PML/RARalpha gene rearrangement in suspected acute promyelocytic leukemia patients using dual-color fluorescence in situ hybridization on bone marrow smears].

To explore the value of detection of PML/RARalpha gene rearrangement on bone marrow smears (BMS) by dual-color fluorescence in situ hybridization (D-FISH) for the diagnosis of acute promyelocytic leukemia (APL), the locus-specific probes for PML and RARalpha genes labeled directly and respectively by Spectrum Green and Spectrum Orange and the D-FISH technique were used to detect the PML/RARalpha gene rearrangement on BMS in 27 suspected APL patients. The results were compared with that of conventional cytogentics (CCG) and reverse transcriptase polymerase chain reaction (RT-PCR). The results showed that out of 18 newly diagnosed patients 14 were found having t(15;17) translocation by CCG and PML/RARalpha gene rearrangement were confirmed by BMS-D-FISH and RT-PCR. Thus, their APL diagnosis was determined; out of 4 patients in whom t(15;17) translocation was not detected by CCG, one had positive BMS-D-FISH and RT-PCR results, thus, this case was considered as having a cryptic t(15;17) translocation, three had negative BMS-D-FISH and RT-PCR results, thus, they were diagnosed as having acute myeloid leukemia rather than APL. In 9 cases with remission, one case with partial remission was found having t(15;17) translocation by CCG, and he had positive BMS-D-FISH and RT-PCR results, the other 8 patients (6 cases with normal karyotype and 2 cases without CCG examination) displayed different BMS-D-FISH and RT-PCR results: negative in 6 cases, but positive in 2 cases. The 2 cases were believed that they survived with minimal residual disease (MRD). It is concluded that BMS-D-FISH is a sensitive and reliable method for the detection of PML/RARalpha rearrangement. It is helpful for diagnosing APL and monitoring its MRD, and especially fit to those patients presenting a cryptic translocation or with failed cytogenetics, lacking suitable material for RT-PCR, as well as needing retrospective study.

Hybridization biosensor using di(2,2'-bipyridine)osmium (III) as electrochemical indicator for detection of polymerase chain reaction product of hepatitis B virus DNA.

A novel hepatitis B virus (HBV) DNA biosensor was developed by immobilizing covalently single-stranded HBV DNA fragments to a gold electrode surface via carboxylate ester to link the 3(')-hydroxy end of the DNA with the carboxyl of the thioglycolic acid (TGA) monolayer. A short-stranded HBV DNA fragment (181bp) of known sequence was obtained and amplified by PCR. The surface hybridization of the immobilized single-stranded HBV DNA fragment with its complementary DNA fragment was evidenced by electrochemical methods using [Os(bpy)(2)Cl(2)](+) as a novel electroactive indicator. The formation of double-stranded HBV DNA on the gold electrode resulted in a great increase in the peak currents of [Os(bpy)(2)Cl(2)](+) in comparison with those obtained at a bare or single-stranded HBV DNA-modified electrode. The mismatching experiment indicated that the surface hybridization was specific. The difference between the responses of [Os(bpy)(2)Cl(2)](+) at single-stranded and double-stranded DNA/TGA gold electrodes suggested that the label-free hybridization biosensor could be conveniently used to monitor DNA hybridization with a high sensitivity. X-ray photoelectron spectrometry technique has been employed to characterize the immobilization of single-stranded HBV DNA on a gold surface.