Evaluation of detection and analysis of chromosome 22q11.2 microdeletion by multiple ligation-dependent probe amplification assay / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To evaluate multiplex ligation-dependent probe amplification (MLPA) assay detection in analysis of chromosome 22q11.2 microdeletion.</p><p><b>METHODS</b>Between March 2008 and September 2009, thirty-two patients including 10 males and 16 females aged between years (3.6±3.1) were selected and evaluated by history, physical examination and medical records. Of these patients, sixteen patients who were previous diagnostic as 22q11.2 microdeletion were in positive control group, the other 16 healthy children were in negative control group. All the patients were detected by MLPA and fluorescence in situ hybridization (FISH) for the presence of a 22q11.2 microdeletion after informed consent. Diagnostic efficacy was assessed by sensitivity, specificity and Kappa analysis.</p><p><b>RESULTS</b>We have applied the two assays of detection of chromosome 22q11.2 microdeletion in 32 patients. Sixteen patients in positive control group were found to have a 22q11.2 deletion and, with the deletion size of 3-Mb. However, as expected, chromosome 22q11.2 deletion was not found in negative control group. The MLPA results were in good agreement with that by FISH. Therefore, MLPA has high sensitivity and specificity.</p><p><b>CONCLUSION</b>MLPA is a rapid, reliable, high-throughput and relatively economical alternative to FISH technology for the diagnosis of 22q11.2 microdeletion. It can provide reliable and helpful information for clinical diagnosis of 22q11.2 microdeletion syndrome.</p>

Chromosome 22q11.2 microdeletion and phenotype analysis of patients with non-syndromic tetralogy of Fallot / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To investigate the frequency and clinical phenotypes of 22q11.2 microdeletion in patients with non-syndromic tetralogy of Fallot (TOF).</p><p><b>METHODS</b>Six-eight non-syndromic TOF patients (38 males and 30 females, aged 0-11 years) were selected and evaluated by history, physical examination and review of medical records. After informed consent was obtained, peripheral blood was drawn for genomic DNA extraction. Chromosome 22q11.2 microdeletion was screened by multiplex ligation-dependent probe amplification (MLPA). Suspected cases were confirmed with fluorescence in situ hybridization (FISH). Data was analyzed with SPSS 11.5 software. Phenotype-genotype correlations were assessed using Fisher's exact test. P values less than 0.05 on a 2-sided test were considered to be significant.</p><p><b>RESULTS</b>Six-eight non-syndromic TOF children were screened for a 22q11.2 deletion, among which 59 (86.8%) presented pulmonary stenosis (PS) and 9 (13.2%) presented pulmonary atresia (PA). Seven patients (10.3%) were found to have carried a deletion. Among these, four had TOF-PS, three had TOF-PA. The frequency of 22q11.2 deletion in patients with TOF-PA (3/9, 33.3%) is much higher than that of TOF-PS (4/59, 6.80%) (P< 0.05).</p><p><b>CONCLUSION</b>22q11.2 microdeletion is present in approximately 10.3% of patients with non-syndromic TOF. The deletion tends to have a higher prevalence in patients with TOF-PA. 22q11.2 deletion should be screened in non-syndromic TOF children and genetic counselling may be provided.</p>