Probable right ventricular dysplasia and patent foramen ovale presenting with cyanosis and clubbing in a patient with characteristics of Noonan syndrome

Mediating ERK 1/2 signaling rescues congenital heart defects in a mouse model of Noonan syndrome

Noonan syndrome (NS) is an autosomal dominant disorder characterized by a wide spectrum of defects, which most frequently include proportionate short stature, craniofacial anomalies, and congenital heart disease (CHD). NS is the most common nonchromosomal cause of CHD, and 80%-90% of NS patients have cardiac involvement. Mutations within the protein tyrosine phosphatase Src homology region 2, phosphatase 2 (SHP2) are responsible for approximately 50% of the cases of NS with cardiac involvement. To understand the developmental stage- and cell type-specific consequences of the NS SHP2 gain-of-function mutation, Q79R, we generated transgenic mice in which the mutated protein was expressed during gestation or following birth in cardiomyocytes. Q79R SHP2 embryonic hearts showed altered cardiomyocyte cell cycling, ventricular noncompaction, and ventricular septal defects, while, in the postnatal cardiomyocyte, Q79R SHP2 expression was completely benign. Fetal expression of Q79R led to the specific activation of the ERK1/2 pathway, and breeding of the Q79R transgenics into ERK1/2-null backgrounds confirmed the pathway's necessity and sufficiency in mediating mutant SHP2's effects. Our data establish the developmental stage-specific effects of Q79R cardiac expression in NS; show that ablation of subsequent ERK1/2 activation prevents the development of cardiac abnormalities; and suggest that ERK1/2 modulation could have important implications for developing therapeutic strategies in CHD.

Hypoxemia related to right-to-left shunting through a patent foramen ovale: successful percutaneous treatment with the CardioSeal device

Hypoxemia related to right-to-left shunting through a patent foramen ovale (PFO) is not rare. It can be observed in correlation with a specific situation such as pneumonectomy and can occur even with normal pulmonary pressure. This article reports the experience of 12 patients in which a transcatheter closure with the CardioSeal device was done successfully. Clinical improvement is often obtained, despite incomplete occlusion of the defects. The author demonstrated that transcatheter closure of PFO can be performed safety and should be considered as an efficient alternative to surgery in cyanotic patients with PFO.

Restrictive and hypertrophic cardiomyopathies in Noonan syndrome: the overlap syndromes

A woman with Noonan syndrome had clinical and haemodynamic features of restrictive cardiomyopathy. There was no ventricular hypertrophy on echocardiography but myocardial biopsies showed myocyte hypertrophy without pathological disarray. This case illustrates the overlap of the cardiac phenotypes of Noonan syndrome, restrictive cardiomyopathy, and hypertrophic cardiomyopathy.