SCN1A Variants as the Underlying Cause of Genetic Epilepsy with Febrile Seizures Plus in Two Multi-Generational Colombian Families.

Genetic epilepsy with febrile seizures plus (GEFS+) is an autosomal dominant disorder with febrile or afebrile seizures that exhibits phenotypic variability. Only a few variants in SCN1A have been previously characterized for GEFS+, in Latin American populations where studies on the genetic and phenotypic spectrum of GEFS+ are scarce. We evaluated members in two multi-generational Colombian Paisa families whose affected members present with classic GEFS+. Exome and Sanger sequencing were used to detect the causal variants in these families. In each of these families, we identified variants in SCN1A causing GEFS+ with incomplete penetrance. In Family 047, we identified a heterozygous variant (c.3530C > G; p.(Pro1177Arg)) that segregates with GEFS+ in 15 affected individuals. In Family 167, we identified a previously unreported variant (c.725A > G; p.(Gln242Arg)) that segregates with the disease in a family with four affected members. Both variants are located in a cytoplasmic loop region in SCN1A and based on our findings the variants are classified as pathogenic and likely pathogenic, respectively. Our results expand the genotypic and phenotypic spectrum associated with SCN1A variants and will aid in improving molecular diagnostics and counseling in Latin American and other populations.

The Impact of Rapid Exome Sequencing on Medical Management of Critically Ill Children.

OBJECTIVES: To evaluate the clinical usefulness of rapid exome sequencing (rES) in critically ill children with likely genetic disease using a standardized process at a single institution. To provide evidence that rES with should become standard of care for this patient population. STUDY DESIGN: We implemented a process to provide clinical-grade rES to eligible children at a single institution. Eligibility included (a) recommendation of rES by a consulting geneticist, (b) monogenic disorder suspected, (c) rapid diagnosis predicted to affect inpatient management, (d) pretest counseling provided by an appropriate provider, and (e) unanimous approval by a committee of 4 geneticists. Trio exome sequencing was sent to a reference laboratory that provided verbal report within 7-10 days. Clinical outcomes related to rES were prospectively collected. Input from geneticists, genetic counselors, pathologists, neonatologists, and critical care pediatricians was collected to identify changes in management related to rES. RESULTS: There were 54 patients who were eligible for rES over a 34-month study period. Of these patients, 46 underwent rES, 24 of whom (52%) had at least 1 change in management related to rES. In 20 patients (43%), a molecular diagnosis was achieved, demonstrating that nondiagnostic exomes could change medical management in some cases. Overall, 84% of patients were under 1 month old at rES request and the mean turnaround time was 9 days. CONCLUSIONS: rES testing has a significant impact on the management of critically ill children with suspected monogenic disease and should be considered standard of care for tertiary institutions who can provide coordinated genetics expertise.