Investigation of QF-PCR application for rapid prenatal diagnosis of chromosomal aneuploidies in Iranian population

G-Banding followed by standard chromosome analysis is routinely used for prenatal detection of chromosomal abnormalities. In recent years, molecular cytogenetic techniques have been developed for rapid diagnosis of chromosomal abnormalities. Among these methods Quantitative Florescence Polymerase Chain Reaction [QF-PCR] has been widely used for this purpose. Heterozygosity of short tandem repeat [STR] markers which leads to informativity is the most critical requirement for feasibility of QF-PCR. In this study we analyzed several short tandem repeats on chromosomes 13, 18, 21, X and Y on amniotic fluid samples obtained from PND candidates to diagnose conditions such as Down, Edward and Patau syndromes and also numerical sex chromosome abnormalities such as Klinefelter and Turner syndromes. Most of the analyzed STRs had acceptable heterozygosity [66.3-94.7] to be used in QF-PCR based prenatal diagnosis. Moreover, results obtained from both methods [standard karyotype and QF-PCR] for all samples were in accordance with each other. In case of using appropriate STR markers, and in certain clinical indications, QF-PCR could be used as useful technique for prenatal diagnosis even in consanguine populations such as Iranians

Microdeletion study in children with selective congenital heart disease; an Iranian multicenter study

Determining the frequency of chromosome 22q11.2 microdeletion in children with congenital cardiac conotruncal abnormalities using Fluorescence in-situ Hybridization [FISH] technique and estimating relation between DiGeorge Syndrome and cardiac conotruncal abnormalities. One-hundred and eighty cases [106 Males, 74 Females] with selective congenital heart disease [conotruncal abnormalities] referred to the hospitals affiliated to Tehran University during 2004-2007 were evaluated by pediatric cardiologists. All patients were assessed for chromosome 22q11.2 microdeletion using FISH technique. Consequently, patients with 22q microdeletion were studied for T cell abnormalities. Median age of the patients at the time of study was 18 months [3d-16y]. The microdeletion of chromosome 22q11.2 was detected in 17 [9.5%] patients with conotruncal abnormalities, including 5 [29.4%] Tetralogy of Fallot plus Supravalvular Pulmonary Stenosis, 4 [23%] Truncus Arteriosus, 5 [29.4%] Pulmonary Artesia with Ventricular Septal Defect, 2 [11.8%] CO AO+Intrrupted Aortic Arch and one case of Valvular Pulmonary Stenosis. Five of uncorrelated cases had crananiofacial dysmorphism. Chromosome 22q11.2 microdeletion FISH study should be considered in patients with cardiac lesions particularly conotruncal abnormality with or without syndromic problems [craniofacial dysmorphism and developmental delay] to provide an appropriate genetic counseling with more accurate estimation of recurrence risk and ultimately prenatal diagnosis in affected families