The SCN5A gene is implicated in many arrhythmogenic and cardiomyopathic processes. We identified a novel SCN5A variant in a family with significant segregation in individuals affected with progressive sinus and atrioventricular nodal disease, atrial arrhythmia, dilated cardiomyopathy, and early sudden cardiac arrest.

A patient pedigree was created following the clinical evaluation of three affected individuals, two monozygotic twins and a paternal half-brother, which lead to the evaluation of a paternal half-sister (four siblings with the same father and three mothers) all of whom experienced varying degrees of atrial arrhythmias, conduction disease, and dilated cardiomyopathy in addition to a paternal history of unexplained death in his 50s with similar autopsy findings. The index male underwent sequencing of 58 genes associated with cardiomyopathies. Sanger sequencing was used to provide data for bases with insufficient coverage and for bases in some known regions of genomic segmental duplications. All clinically significant and novel variants were confirmed by independent Sanger sequencing.

All relatives tested were shown to have the same SCN5A variant of unknown significance (p. Asp197His) and the monozygotic twins shared a co-occurring NEXN (p. Glu575*). Segregation analysis demonstrates likely pathogenic trait for the SCN5A variant with an additional possible role for the NEXN variant in combination.

There is compelling clinical evidence suggesting that the SCN5A variant p. Asp197His may be re-classified as likely pathogenic based on the segregation analysis of our family of interest. Molecular mechanism studies are pending.

Infants with critical congenital heart disease who require cardiothoracic surgical intervention may have significant post-operative mortality and morbidity. Infants who are small for gestational age <10th percentile with foetal growth restriction may have end-organ dysfunction that may predispose them to increased morbidity or mortality.

A single-institution retrospective review was performed in 230 infants with congenital heart disease who had cardiothoracic surgical intervention <60 days of age. Pre-, peri-, and post-operative morbidity and mortality markers were collected along with demographics and anthropometric measurements.

There were 230 infants, 57 (23.3%) small for gestational age and 173 (70.6%) appropriate for gestational age. No significant difference was noted in pre-operative markers – gestational age, age at surgery, corrected gestational age, Society for Thoracic Surgeons and European Association for Cardiothoracic Surgery mortality score; or post-operative factors – length of stay, ventilation days, arrhythmias, need for extracorporeal membrane oxygenation, vocal cord dysfunction, hearing loss; or end-organ dysfunction – gastro-intestinal, renal, central nervous system, or genetic. Small for gestational age infants were more likely to have failed vision tests (p = 0.006). Small for gestational age infants were more likely to have increased 30-day (p = 0.005) and discharge mortality (p = 0.035). Small for gestational age infants with normal birth weight (>2500 g) were also at increased risk of 30-day mortality compared with appropriate for gestational age infants (p = 0.045).

Small for gestational age infants with congenital heart disease who undergo cardiothoracic surgery <60 days of age have increased risk of mortality and failed vision screening. Assessment of foetal growth restriction as part of routine pre-operative screening may be beneficial.