Arterial ischemic stroke in children with congenital heart diseases

Somatic GATA4 mutation contributes to tetralogy of Fallot

Tetralogy of Fallot (TOF) is the most prevalent cyanotic congenital heart pathology and causes infant morbidity and mortality worldwide. GATA-binding protein 4 (GATA4) serves as a pivotal transcriptional factor for embryonic cardiogenesis and germline GATA4 mutations are causally linked to TOF. However, the effects of somatic GATA4 mutations on the pathogenesis of TOF remain to be ascertained. In the present study, sequencing assay of GATA4 was performed utilizing genomic DNA derived from resected heart tissue specimens as well as matched peripheral blood specimens of 62 patients with non-familial TOF who underwent surgical treatment for TOF. Sequencing of GATA4 was also performed using the heart tissue specimens as well as matched peripheral venous blood samples of 68 sporadic cases who underwent heart valve displacement because of rheumatic heart disorder and the peripheral venous whole blood samples of 216 healthy subjects. The function of the mutant was explored by dual-luciferase activity analysis. Consequently, a new GATA4 mutation, NM_002052.5:c.708T>G;p.(Tyr236*), was found in the heart tissue of one patient with TOF. No mutation was detected in the heart tissue of the 68 cases suffering from rheumatic heart disorder or in the venous blood samples of all 346 individuals. GATA4 mutant failed to transactivate its target gene, myosin heavy chain 6. Additionally, this mutation nullified the synergistic transactivation between GATA4 and T-box transcription factor 5 or NK2 homeobox 5, two genes causative for TOF. Somatic GATA4 mutation predisposes TOF, highlighting the significant contribution of somatic variations to the molecular pathogenesis underpinning TOF.

Advances in the Diagnosis and Treatment of Pediatric Arterial Ischemic Stroke

Though rare, stroke in infants and children is an important cause of mortality and chronic morbidity in the pediatric population. Neuroimaging advances and implementation of pediatric stroke care protocols have led to the ability to rapidly diagnose stroke and in many cases determine the stroke etiology. Though data on efficacy of hyperacute therapies, such as intravenous thrombolysis and mechanical thrombectomy, in pediatric stroke are limited, feasibility and safety data are mounting and support careful consideration of these treatments for childhood stroke. Recent therapeutic advances allow for targeted stroke prevention efforts in high-risk conditions, such as moyamoya, sickle cell disease, cardiac disease, and genetic disorders. Despite these exciting advances, important knowledge gaps persist, including optimal dosing and type of thrombolytic agents, inclusion criteria for mechanical thrombectomy, the role of immunomodulatory therapies for focal cerebral arteriopathy, optimal long-term antithrombotic strategies, the role of patent foramen ovale closure in pediatric stroke, and optimal rehabilitation strategies after stroke of the developing brain.