A de novo partial 5p deletion and cryptic 18p duplication detected by SNP-Array in a boy featuring Cri du Chat syndrome / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To determine the karyotype of a boy suspected to have Cri du Chat syndrome with severe clinical manifestations, and to assess the recurrence risk for his family.</p><p><b>METHODS</b>High-resolution GTG banding was performed to analyze the patient and his parents. Fluorescence in situ hybridization (FISH) with Cri du Chat syndrome region probe as well as subregional probes mapped to 5pter, 5qter, 18pter, 18qter, and whole chromosome painting probe 18 was performed to analyze the patient and his parents. In addition, single nucleotide polymorphism-based arrays (SNP-Array) analysis with Affymetrix GeneChip Genome-wide Human SNP Nsp/Sty 6.0 were also performed to analyze the patient.</p><p><b>RESULTS</b>Karyotype analysis indicated that the patient has carried a terminal deletion in 5p. FISH with Cri du Chat syndrome region probe confirmed that D5S23 and D5S721 loci are deleted. SNP-Array has detected a 15 Mb deletion at 5p and a 2 Mb duplication at 18p. FISH with 5p subtelomeric probes and 18p subtelomeric probe further confirmed that the derivative chromosome 5 has derived from a translocation between 5p and 18p, which has given rise to a 46,XY,der(5)t(5;18)(p15.1;p11.31)dn karyotype.</p><p><b>CONCLUSION</b>A de novo 5p partial deletion in conjunction with a cryptic 18p duplication has been detected in a boy featuring Cri-du-Chat syndrome. His parents, both with negative findings, have a low recurrence risk. For its ability to detect chromosomal imbalance, SNP-Array has a great value for counseling of similar patients and assessment of recurrence risks.</p>

Study on the detection of P. gingivalis, A. actinomycetemcomitans and T. denticola and the correlation between coinfections of the microbes and levels of chronic periodontitis lesion / 中华流行病学杂志

<p><b>OBJECTIVE</b>To establish a 16S rDNA multiplex polymerase chain reaction (PCR) for simultaneously detecting P. gingivalis, A. actinomycetemcomitans and T. denticola in clinical specimens of chronic periodontitis and to study the correlation between different modes of infection and severity of the disease.</p><p><b>METHODS</b>Periodontal pocket specimens from 152 patients with mild, moderate or advanced chronic periodontitis and gingival sulcus specimens from 30 periodontally healthy individuals were collected and placed in 200 microl lysis buffer. The specimens were incubated in 100 degrees C for 10 min and 10 microl of the supernatant was directly used as PCR template. DNAs from P. gingivalis strain ATCC33277, A. actinomycetemcomitans strain Y4, T. denticola strain FM and E. coli strain DH5alpha were used as positive and negative controls in PCR with all of which were prepared by routing phenol-chloroform method. A multiplex PCR assay, using three sets of primers specific to 16S rDNA genes of the three anaerobes, was developed to detect the specimens. The target amplification fragments from 3 cases of PCR products positive for all the three anaerobes were sequenced after T-A cloning. Chi-square test was applied to analyze the correlation between different coinfection of the three anaerobes and severity of the disease.</p><p><b>RESULTS</b>The established 16S rDNA multiplex PCR assay was able to detect P. gingivalis, A. actinomycetemcomitans and T. denticola at a minimum of 10, 20 and 20 cells, respectively. In comparison with the reported corresponding sequences, similarities of the nucleotide sequences from the three anaerobes 16S rDNA amplification fragments were as high as 99.45%, 97.08% and 96.59%, respectively. Of the 30 periodontally healthy gingival sulcus specimens, only one (3.3%) positive for P. gingivalis and two (6.7%) for A. actinomycetemcomitans could be identified but all of the rest were negative. In the 152 CP periodontal pocket specimens, 147 cases (96.7%) were positive for P. gingivalis, A. actinomycetemcomitans and/or T. denticola, respectively, and 5 cases (3.3%) were negative for all the three anaerobes. The positive rate of P. gingivalis detection (91.5%, 139/152) was significantly higher than those of A. actinomycetemcomitans (72.4%, 110/152) and T. denticola (80.9%, 123/152) (chi(2) = 7.07, 18.67; P < 0.01). 89.8% of the specimens from patients showed coinfections with two (26.5%) or three anaerobes (63.3%), and the coinfection rates in the specimens from moderate and advanced CP were remarkably higher than that from mild CP (chi(2) = 10.43, P < 0.01).</p><p><b>CONCLUSION</b>The 16S rDNA multiplex PCR established in this study showed high sensitivity and specificity, which could be used to detect P. gingivalis, A. actinomycetemcomitans and T. denticola in clinical specimens. CP was an disease caused by multiple pathogenic microbes while the synergistic pathopoiesis of the three microbes was closely related to the severity of the disease.</p>