Detailed mapping of a congenital heart disease gene in chromosome 3p25
JOURNAL OF MEDICAL GENETICS
Authors: Green, EK; Priestley, MD; Waters, J; Maliszewska, C; Latif, F; Maher, ER
Abstract
Distal deletion of chromosome 3p25-pter (3p(-) syndrome) produces a distinct clinical syndrome characterised by low birth weight, mental retardation, telecanthus, ptosis, and micrognathia. Congenital heart disease (CHD), typically atrioventricular septal defect (AVSD), occurs in about a third of patients. In total, approximately 25 cases of 3p(-) syndrome have been reported world wide. We previously analysed five cases and showed that (1) the 3p25-pter deletions were variable and (2) the presence of CHD correlated with the proximal extent of the deletion, mapping a CHD gene centromeric to D3S18. To define the molecular pathology of the 3p(-) syndrome further, we have now proceeded to analyse the deletion region in a total of 10 patients (five with CHD), using a combination of FISH analysis and polymorphic markers, for up to 21 loci from 3p25-p26. These additional investigations further supported the location of an AVSD locus within 3p25 and refined its localisation. Thus, the critical region was reduced to an interval between D3S1263 and D3S3594. Candidate 3p25 CHD genes, such as PMCA2 (ATP2B2), fibulin 2, TIMP4, and Sec13R, were shown to map outside the target interval. Additionally, the critical region for the phenotypic features of the 3p(-) phenotype was mapped to D3S1317 to D3S17 (19-21 cM). These findings will accelerate the identification of the 3p25 CHD susceptibility locus and facilitate investigations of the role of this locus in non-syndromic AVSDs, which are a common form of familial and isolated CHD.
Expression of Extracellular Matrix Genes During Myocardial Recovery From Heart Failure After Left Ventricular Assist Device Support
JOURNAL OF HEART AND LUNG TRANSPLANTATION
Authors: Felkin, Leanne E.; Lara-Pezzi, Enrique; George, Robert; Yacoub, Magdi H.; Birks, Emma J.; Barton, Paul J. R.
Abstract
Background: Abnormalities in the extracellular matrix (ECM) can occur in heart failure. in this study we analyzed ECM gene expression in patients with advanced dilated cardiomyopathy who did and did not develop sustained myocardial recovery after left ventricular asst device (LVAD) unloading combined with pharmacologic therapy. Methods: Myocardial gene expression of collagens (COL1A1 and COL3A1), fibronectin (FN), matrix metalloproteinases (MMPs 1 to 14), tissue inhibitors of metalloproteinases (TIMPs 1 to 4), connective tissue growth factor (CTGF), transforming growth factor-betal (TGF-beta 1) and THY1 was measured by real-time reverse transcriptase-polymerase chain reaction (RT-PCR) at LVAD implantation and again at explantation (recovery, n = 11) or transplantation (non-recovery, n = 5). Results: The non-recovery group had higher levels of pro-fibrotic markers (COL1A1, TGF-beta 1 and THY1) at implantation compared with the recovery group (1.82 +/- 0.74-, 1.81 +/- 0.69-, and 3.01 +/- 1.70-fold, respectively; p <= 0.05). Both recovery and non-recovery groups showed no significant difference in gene expression after treatment, but levels of pro-fibrotic genes (COL1A1, COL3A1, FN and THY1) correlated negatively with post-explant ejection fraction in the recovery group. Of all genes analyzed only TIMP4 showed a significant change, with expression reduced during recovery (0,55 0.25-fold at explant vs implant, p = 0.001). All other genes showed complex patterns between individuals with both increased and decreased expression of pro-fibrotic markers, MMPs and TIMPs in recovery patients. Conclusions: Patients who did not recover had higher myocardial expression of pro-fibrotic genes at LVAD implantation, and in recovered patients higher levels at explant were negatively associated with subsequent ejection fraction. However, individual patients showed complex expression patterns and a decrease in pro-fibrotic markers was not required for recovery. J Heart Lung Transplant 2009; 28:117-22. Copyright (C) 2009 by the International Society for Heart and Lung Transplantation.