Analysis of DMD gene mutations in 59 families in northern China / 中华检验医学杂志

Objective To detect the DMD gene mutation sites and the regions of breakpoints in Duchenne/Becker muscular dystrophy (DMD/BMD) patients in northern China. Methods Multiplex amplifiable probe hybridization (MLPA) was used to detect the mutation in 59 cases (51 cases with DMD and 8 with BMD) from northern China and dystrophin gene mutations in their parents. Results From northern China and dystrophin gene mutations 59 families found gene deletions in 33 cases of 59 DMD/BMD patients (55.9%), duplications in 6 cases (10. 2%) and point mutation in one case (1.7%). Intron 44 was most frequently affected (n = 13, 33.3%), followed by intron 50 (n = 11, 28.2%) and intron 45 (n=8, 20.5%). The novel mutations were identified, in two patients including two independent duplications carried by patient D1 149 and a point mutation [5208del(A)] carried by patient D1 65, which were not included in Leiden database. In addition, an exon 22 deletion was found in one patient, which was the first reported case in Chinese patients. Conclusions Deletions are mostly located in the hotspot between exon 45 and 50. Duplications mostly occurred in the 5' end of the gene. Intron 44 is the most frequently affected breakpoint in northern Chinese population.

Rapid prenatal detection of Down syndrome by homologous gene quantitative PCR / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To evaluate the use of homologous gene quantitative PCR (HGQ-PCR) as a method for non-invasive diagnosis of Down syndrome and for prevention of the birth of Down syndrome children.</p><p><b>METHODS</b>HGQ-PCR, which can directly detect the additional copy of chromosome 21 by comparing simultaneously amplified two highly homologous genes, i.e. the human liver-type phosphofructokinase located on chromosome 21 critical region of Down syndrome (PFKL-CH21) and the human muscle-type phosphofructokinase located on chromosome 1 (PFKM-CH1), was performed in 38 clinically diagnosed Down syndrome patients and 178 normal controls.</p><p><b>RESULTS</b>The ratios of PFKM-CH1/PFKL-CH21 products were 1.40 +/- 0.367 (mean +/- SD) and 0.46 +/- 0.21 (mean +/- SD) for disomy 21 and trisomy 21, respectively. The difference between these two groups was statistically significant (P<0.001).</p><p><b>CONCLUSION</b>This approach has proven to be a practical and direct method for the detection of trisomy 21 and may also be applied to the detection of the extra piece of 21q involved in translocation-type of Down syndrome.</p>

Use of specific antibody to detect fetal erythroblasts in maternal circulation / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To investigate the feasibility of using immunohistochemical technique to detect the presence of fetal erythroblasts in the maternal circulation for prenatal diagnosis.</p><p><b>METHODS</b>Maternal blood was obtained from 30 pregnant women at 8 to 26 weeks of gestation. Nucleated red blood cells (NRBCs) were separated with Percoll using a discontinuous density gradient method, and then smeared on microscope slides using cytocentrifugation. Slides were stained with antibody against the gamma-chain of fetal hemoglobin (HbF). All positive NRBCs were collected by micromanipulator under microscopic observation, and then amplified by improved primer extension preamplification(PEP). Sex and Duchenne's musclar dystrophy (DMD) genetic diagnosis were determined from a small aliquot of the PEP reaction.</p><p><b>RESULTS</b>NRBCs stained with HbF were found in all of the blood from the 30 pregnant women at 8 to 26 weeks of gestation. 17 male fetuses and 13 female fetuses were detected in the 30 cases. These results coincided with those of induced labor or amniotic fluid control, and 8 fetuses at the risk of DMD were diagnosed.</p><p><b>CONCLUSION</b>This diagnostic method using immunohistochemical technique to mark fetal NRBC shows good application prospects.</p>

Homozygous deletion of p16 and p15 genes in laryngeal squamous cell carcinoma / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To assess the relationship of homozygous deletion status of p16 (MTS1/INK4a/CDKN2A), p15(MTS2/INK4b/CDKN2B) genes and laryngeal squamous cell carcinoma(LSCC) progression.</p><p><b>METHODS</b>DNA was extracted from fresh tumors. Homozygous deletion of p16 exon 2(p16E2) in 80 cases of LSCC and p15 exon 2(p15E2) in 67 cases of LSCC were detected by the polymerase chain reaction technique.</p><p><b>RESULTS</b>The p16E2 deletion rate in 80 cases was 12.5%(10/80); the p15E2 deletion rate in 67 cases was 11.94%(8/67); the p16E2 and p15E2 codeletion rate in 67 cases was 5.97%(4/67).</p><p><b>CONCLUSION</b>Homozygous deletion of p16E2 and p15E2 is related with LSCC oncogenesis, and it may play a role to some extent in LSCC malignant progression.</p>