Identification of variants of ISL1 gene promoter and cellular functions in isolated ventricular septal defects

Ventricular septal defects (VSDs) are the most common congenital heart defects (CHDs). Studies have documented that ISL1 has a crucial impact on cardiac growth, but the role of variants in the ISL1 gene promoter in patients with VSD has not been explored. In 400 subjects (200 patients with isolated and sporadic VSDs: 200 healthy controls), we investigated the ISL1 gene promoter variant and performed cellular functional experiments by using the dual-luciferase reporter assay to verify the impact on gene expression. In the ISL1 promoter, five variants were found only in patients with VSD by sequencing. Cellular functional experiments demonstrated that three variants decreased the transcriptional activity of the ISL1 promoter (P < 0.05). Further analysis with the online JASPAR database demonstrated that a cluster of putative binding sites for transcription factors may be altered by these variants, possibly resulting in change of ISL1 protein expression and VSD formation. Our study has, for the first time, identified novel variants in the ISL1 gene promoter region in the Han Chinese patients with isolated and sporadic VSD. In addition, the cellular functional experiments, electrophoretic mobility shift assay, and bioinformatic analysis have demonstrated that these variants significantly alter the expression of the ISL1 gene and affect the binding of transcription factors, likely resulting in VSD. Therefore, this study may provide new insights into the role of the gene promoter region for a better understanding of genetic basis of the formation of CHDs and may promote further investigations on mechanism of the formation of CHDs.

Case Report: Clinical Description of a Patient Carrying a 12.48 Mb Microdeletion Involving the 10p13-15.3 Region

Partial deletion of 10p chromosome is a rare chromosomal aberration. Submicroscopic deletion of 10p15.3 is mainly related to cognitive deficits, speech disorders, motor delay, and hypotonia with the deleted region ranging from 0.15 to 4 Mb. The clinical phenotype is mainly determined by the ZMYND11 and DIP2C genes. Here, we report a rare case of feeding difficulties, hypocalcemia, and psychomotor retardation. Our patient has a 12.48 Mb deletion in 10p15.3-10p13, which is the second case of large 10p deletion among reported cases thus far.

Characteristics and outcome of congenital left ventricular aneurysm and diverticulum: Analysis of 809 cases published since 1816

BACKGROUND

Congenital left ventricular aneurysm (LVA) or diverticulum (LVD) is rare cardiac anomalies. We aimed to analyse the clinical characteristics and outcome in all ever published patients.

METHODS

MEDLINE, Web of science, Google and EMBASE, and reference lists of relevant articles were searched for publications reporting on LVA or LVD patients.

RESULTS

We identified 809 patients published since 1816 [354 (49.1%) LVA, 453 (50.6%) LVD, 2 (0.3%) both]. Mean age at diagnosis was 34.1±27 (LVA) and 29.7±27.6years (LVD; p=0.05). 48.9% were male. LVA was larger (38.7±22.5mm versus 31.4±21.2mm; p=0.002) and frequently found in submitral location (33% versus 4.9%; p<0.001), LVD was frequently located at the LV-apex (61.2% versus 28.7%; p<0.001). LVD was often associated with cardiac (34.2% versus 11%; p<0.001) or extracardiac anomalies (32.7% versus 3%; p<0.001). LVA patients presented more frequently with ventricular tachycardia/fibrillation (18.1% versus 13.1%; p=0.01), the incidences of rupture (4% versus 4.5%; p=0.9), syncope (8.3% versus 5.1%; p=0.1), and embolic events (4.9% versus 3.6%; p=0.4) at presentation were not different between LVA and LVD. Mean follow-up was 56.3±43months. Cardiac death occurred more frequently in the LVA group (11.5% versus 5.0%; p=0.05) at a median age of 0.8 [LVA] and 2.5 [LVD] years. The leading cause of cardiac death was congestive heart failure in the LVA-group (50.0% versus 0.0%; p=0.01), and rupture in the LVD-group (75.0% versus 27.3%; p=0.04).

CONCLUSIONS

LVA and LVD are distinct congenital anomalies with different clinical and morphological characteristics. The prognosis of LVA is significantly worse during long-term follow-up.

Cleft lip/palate, short stature, and developmental delay in a boy with a 5.6-mb interstitial deletion involving 10p15.3p14

The chromosome interval 10p15.3p14 harbors about a dozen genes. This region has been implicated in a few well-known human phenotypes, namely HDR syndrome (hypoparathyroidism, sensorineural deafness, and renal dysplasia) and DGS2 (DiGeorge syndrome 2), but a number of variable phenotypes have also been reported. Cleft lip/palate seems to be a very unusual finding within the clinical spectrum of patients with this deletion. Here, we report a male child born with short stature, cleft lip/palate, and feeding problems who was found to have a 5.6-Mb deletion at 10p15.3p14.

Rare de novo copy number variants in patients with congenital pulmonary atresia

Background

Ongoing studies using genomic microarrays and next-generation sequencing have demonstrated that the genetic contributions to cardiovascular diseases have been significantly ignored in the past. The aim of this study was to identify rare copy number variants in individuals with congenital pulmonary atresia (PA).

Methods and Results

Based on the hypothesis that rare structural variants encompassing key genes play an important role in heart development in PA patients, we performed high-resolution genome-wide microarrays for copy number variations (CNVs) in 82 PA patient-parent trios and 189 controls with an Illumina SNP array platform. CNVs were identified in 17/82 patients (20.7%), and eight of these CNVs (9.8%) are considered potentially pathogenic. Five de novo CNVs occurred at two known congenital heart disease (CHD) loci (16p13.1 and 22q11.2). Two de novo CNVs that may affect folate and vitamin B₁₂ metabolism were identified for the first time. A de novo 1-Mb deletion at 17p13.2 may represent a rare genomic disorder that involves mild intellectual disability and associated facial features.

Conclusions

Rare CNVs contribute to the pathogenesis of PA (9.8%), suggesting that the causes of PA are heterogeneous and pleiotropic. Together with previous data from animal models, our results might help identify a link between CHD and folate-mediated one-carbon metabolism (FOCM). With the accumulation of high-resolution SNP array data, these previously undescribed rare CNVs may help reveal critical gene(s) in CHD and may provide novel insights about CHD pathogenesis.

Long-term complications following surgical patch closure of multiple muscular ventricular septal defects

BACKGROUND

Multiple muscular ventricular septal defects (VSDs) in children can be difficult to treat and a range of techniques has been advocated. These include pulmonary artery banding, interventional catheter closure, and a variety of surgical approaches. When there are apical muscular defects and associated coarse trabeculations in the right ventricle (RV) producing a "Swiss cheese" pattern, a large patch extending on to the RV free wall and excluding part of the apex has been used.

METHODS

We assessed four adult patients who had surgery 22 to 45 years ago to treat muscular VSD by patches which excluded the RV apex.

RESULTS

Ages ranged from 22 to 50 years. Re-presentations were for polycythemia, cyanosis, syncope, and atrial flutter. Echocardiography showed bidirectional flow from left ventricle to apex of RV, no pulmonary hypertension, small-sized RV with diastolic dysfunction, enlarged right atria, reopening of patent foramen ovale (PFO) in three, and positive bubble studies with right to left shunting in two. Catheterization confirmed elevated right atrial and RV end diastolic pressures. Two patients had evidence of hepatic cirrhosis. One woman had device closure of PFO, but has right heart failure. One man had redo surgical closure of VSD and PFO. Another patient is being considered for a Glenn shunt to take some load off RV.

CONCLUSIONS

Surgical closure of muscular VSD by large patch with RV apical exclusion gives good early results. However, long term in adult life, the reduced size of RV, and diastolic dysfunction cause problems. These include reopening of PFO with cyanosis, right heart failure, cirrhosis, and arrhythmias.