PURPOSESmooth muscle dysfunction syndrome (SMDS) due to heterozygous ACTA2 arginine 179 alterations is characterized by patent ductus arteriosus, vasculopathy (aneurysm and occlusive lesions), pulmonary arterial hypertension, and other complications in smooth muscle-dependent organs. We sought to define the clinical history of SMDS to develop recommendations for evaluation and management.METHODSMedical records of 33 patients with SMDS (median age 12 years) were abstracted and analyzed.RESULTSAll patients had congenital mydriasis and related pupillary abnormalites at birth and presented in infancy with a patent ductus arteriosus or aorto-pulmonary window. Patients had cerebrovascular disease characterized by small vessel disease (hyperintense periventricular white matter lesions; 95%), intracranial artery stenosis (77%), ischemic strokes (27%), and seizures (18%). Twelve (36%) patients had thoracic aortic aneurysm repair or dissection at median age of 14 years and aortic disease was fully penetrant by the age of 25 years. Three (9%) patients had axillary artery aneurysms complicated by thromboembolic episodes. Nine patients died between the ages of 0.5 and 32 years due to aortic, pulmonary or stroke complications, or unknown causes.CONCLUSIONBased on these data, recommendations are provided for the surveillance and management of SMDS to help prevent early onset life-threatening complications.

Myocarditis has a variable clinical presentation and there is still debate regarding accurate diagnostic criteria. Adding to the controversy surrounding this diagnosis, there is no clear consensus for the treatment or ongoing follow‐up of patients with myocarditis. All of this makes the diagnosis and management of myocarditis a particular challenge in the pediatric population. Furthermore, the literature with respect to this topic is dynamic and ever‐changing. In this review article, we aim to review and summarize the common clinical presentations of myocarditis, along with the latest recommendations for diagnostic criteria, treatment, and follow‐up of patients with myocarditis.

Despite numerous advances in the care of infants with congenital heart disease, necrotising enterocolitis remains a significant source of morbidity and mortality. In these infants, there is no clear relationship between enteral feeding patterns and the development of necrotising enterocolitis in the post-operative period. The benefits of graduated feeding advancements to avoid the development of necrotising enterocolitis remain unproven.

Histiocytoid cardiomyopathy (Histiocytoid CM) is a rare form of cardiomyopathy observed predominantly in newborn females that is fatal unless treated early in life. We have performed whole exome sequencing on five parent-proband trios and identified nuclear-encoded mitochondrial protein mutations in three cases. Two probands had de novo non-sense mutations in the second exon of the X-linked nuclear gene NDUFB11, which has not previously been implicated in any disease, despite evidence that deficiency for other mitochondrial electron transport complex I members leads to cardiomyopathy. A third proband was doubly heterozygous for inherited rare variants in additional components of complex I, NDUFAF2 and NDUFB9, confirming that Histiocytoid CM is genetically heterogeneous. In a fourth case, the proband with Histiocytoid CM inherited a mitochondrial mutation from her heteroplasmic mother, as did her brother who presented with cardiac arrhythmia. Strong candidate recessive or compound heterozygous variants were not found for this individual or for the fifth case. Although NDUFB11 has not been implicated before in cardiac pathology, morpholino-mediated knockdown of Ndufb11 in zebrafish embryos generated defective cardiac tissue with looping defects, which confirms the causative role of NDUFB11 in cardiac pathology. Therefore, the NDUFB11 mutation represents a genetic basis of this heterogeneous disease.