Background Anesthesia given to immature rodents causes cognitive decline raising the possibility that the same might be true for millions of children undergoing surgical procedures under general anesthesia each year. We tested the hypothesis that anesthesia-induced cognitive decline in rats is treatable. We also tested if anesthesia-induced cognitive decline is aggravated by tissue injury. Methods 7-day old rats underwent sevoflurane anesthesia (1 MAC, 4 hours) with or without tail clamping. At 4 weeks, rats were randomized to environmental enrichment or normal housing. At 8 weeks rats underwent neurocognitive testing, which consisted of fear conditioning, spatial reference memory and water maze-based memory consolidation tests, that interrogated working memory, short term memory and early long term memory. Results Sevoflurane-treated rats had a greater escape latency when the delay between memory acquisition and memory retrieval was increased from 1 minute to 1 hour, indicating that short term memory was impaired. Delayed environmental enrichment reversed the effects of sevoflurane on short term memory and generally improved many tested aspects of cognitive function, both in sevoflurane-treated and control animals. The performance of tail clamped rats did not differ from those rats receiving anesthesia alone. Conclusion Sevoflurane-induced cognitive decline in rats is treatable. Delayed environmental enrichment rescued the sevoflurane-induced impairment in short-term memory. Tissue injury did not worsen the anesthesia-induced memory impairment. These findings may have relevance to neonatal and pediatric anesthesia.

Disclaimer: This technical standard is designed primarily as an educational resource for clinical laboratory geneticists to help them provide quality clinical laboratory genetic services. Adherence to this standard is voluntary and does not necessarily assure a successful medical outcome. This standard should not be considered inclusive of all proper procedures and tests or exclusive of other procedures and tests that are reasonably directed to obtaining the same results. In determining the propriety of any specific procedure or test, the clinical laboratory geneticist should apply his or her own professional judgment to the specific circumstances presented by the individual patient or specimen. Clinical laboratory geneticists are encouraged to document in the patient's record the rationale for the use of a particular procedure or test, whether or not it is in conformance with this standard. They also are advised to take notice of the date any particular standard was adopted, and to consider other relevant medical and scientific information that becomes available after that date. It also would be prudent to consider whether intellectual property interests may restrict the performance of certain tests and other procedures. Gene sequencing panels are a powerful diagnostic tool for many clinical presentations associated with genetic disorders. Advances in DNA sequencing technology have made gene panels more economical, flexible, and efficient. Because the genes included on gene panels vary widely between laboratories in gene content (e.g., number, reason for inclusion, evidence level for gene-disease association) and technical completeness (e.g., depth of coverage), standards that address technical and clinical aspects of gene panels are needed. This document serves as a technical standard for laboratories designing, offering, and reporting gene panel testing. Although these principles can apply to multiple indications for genetic testing, the primary focus is on diagnostic gene panels (as opposed to carrier screening or predictive testing) with emphasis on technical considerations for the specific genes being tested. This technical standard specifically addresses the impact of gene panel content on clinical sensitivity, specificity, and validity-in the context of gene evidence for contribution to and strength of evidence for gene-disease association-as well as technical considerations such as sequencing limitations, presence of pseudogenes/ gene families, mosaicism, transcript choice, detection of copynumber variants, reporting, and disclosure of assay limitations.

Pathogenic de novo variants in the X-linked gene SLC35A2 encoding the major Golgi-localized UDP-galactose transporter required for proper protein and lipid glycosylation cause a rare type of congenital disorder of glycosylation known as SLC35A2congenital disorders of glycosylation (CDG; formerly CDG-IIm). To date, 29 unique de novo NG ET AL. | 909

The clinical interpretation of genetic variants has come to rely heavily on reference population databases such as the Exome Aggregation Consortium (ExAC) database. Pathogenic variants in genes associated with severe, pediatric-onset, highly penetrant, autosomal dominant conditions are assumed to be absent or rare in these databases. Exome sequencing of a six-year-old female patient with seizures, developmental delay, dysmorphic features and failure to thrive identified an ASXL1 variant previously reported as causative of Bohring-Opitz syndrome (BOS). Surprisingly, the variant was observed seven times in the ExAC database, presumably in individuals without BOS. Although the BOS phenotype fit, the presence of the variant in reference population databases introduced ambiguity in result interpretation. Review of the literature revealed that acquired somatic mosaicism of ASXL1 variants (including pathogenic variants) during hematopoietic clonal expansion can occur with aging in healthy individuals. We examined all ASXL1 truncating variants in the ExAC database and determined most are likely somatic. Failure to consider somatic mosaicism may lead to the inaccurate assumption that conditions like Bohring-Opitz syndrome have reduced penetrance, or the misclassification of potentially pathogenic variants.

De novo, germline variants in DNMT3A cause Tatton-Brown-Rahman syndrome (TBRS). This condition is characterized by overgrowth, distinctive facial appearance, and intellectual disability. Somatic DNMT3A variants frequently occur in hematologic malignances, particularly acute myeloid leukemia. The Arg882 residue is the most common site of somatic DNMT3A variants, and has also been altered in patients with TBRS. Here we present three additional patients with this disorder attributed to DNMT3A germline variants that disrupt the Arg882 codon, suggesting that this codon may be a germline mutation hotspot in this disorder. Furthermore, based on the investigation of previously reported variants in patients with TBRS, we found overlap in the spectrum of DNMT3A variants observed in this disorder and somatic variants in hematological malignancies.

The interpretation of genetic variants identified during clinical sequencing has come to rely heavily on reference population databases such as the Exome Aggregation Consortium (ExAC).Genuinely pathogenic variants, particularly in genes associated with severe autosomal dominant conditions, are assumed to be absent or extremely rare in these databases. Clinical exome sequencing of a six-year-old female patient with seizures, global developmental delay, dysmorphic features and failure to thrive identified an ASXL1 variant that was previously reported as causative of Bohring-Opitz syndrome (BOS). Surprisingly, the variant was observed seven times in the ExAC database, presumably in individuals without BOS. Although the BOS phenotype matched the presentation of the patient, the presence of the variant in reference population databases introduced ambiguity in result interpretation. Interrogation of the literature revealed that acquired somatic mosaicism of ASXL1 variants (including known pathogenic variants) during hematopoietic clonal expansion may be concomitant with aging in healthy individuals. We examined all high quality ASXL1 predicted truncating variant calls in the ExAC database and determined the majority could be attributed to this phenomenon. Failure to consider somatic mosaicism may lead to the inaccurate assumption that conditions like Bohring-Opitz syndrome have reduced penetrance, or the misclassification of potentially pathogenic variants.

The NONO gene encodes a nuclear protein involved in RNA metabolism. Hemizygous loss-offunction NONO variants have been associated with syndromic intellectual disability and with left ventricular noncompaction (LVNC). A two-year-old boy presented to the University of Utah's Penelope Undiagnosed Disease Program with developmental delay, nonfamilial features, relative macrocephaly, and dilated cardiomyopathy with LVNC and Ebstein anomaly. Brain MRI showed a thick corpus callosum, mild Chiari I malformation, and a flattened pituitary. Exome sequencing identified a novel intronic deletion (c.154+5_154+6delGT) in the NONO gene. Splicing studies demonstrated intron 4 read-through and the use of an alternative donor causing the frameshift p.Asn52Serfs*6.Family segregation analysis showed that the variant occurred de novo in the boy's unaffected mother. MRI and endocrine findings suggest that hypopituitarism may contribute to growth failure, abnormal thyroid hormone levels, cryptorchidism, or delayed puberty in patients with NONOassociated disease. Also, including this case LVNC has been observed in five out of eight patients, and this report also confirms an association between loss of NONO and Ebstein anomaly. In some cases, unrelated individuals share the same pathogenic NONO variants but do not all have clinically significant LVNC, suggesting that additional modifiers may contribute to cardiac phenotypes. K E Y W O R D S Ebstein anomaly, left ventricular noncompaction, NONO, splicing variant, syndromic intellectual disability 1 | INTRODUCTION The nonoctamer-containing, POU-domain DNA-binding protein (NONO) is a highly conserved, member of the Drosophila behavior/human splicing (DBHS) protein family thought to be involved in various aspects of RNA metabolism (Shav-Tal and Zipori, 2002). Mice lacking NONO have small cerebellums, spatial memory impairment, and changes at inhibitory synapses (Mircsof et al., 2015). Immunohistochemistry indicates that NONO is broadly expressed in mouse tissues, including in neurons and granule cells of the cortex and hippocampus (Mircsof et al., 2015) as well as in the heart (Scott et al., 2017). Hemizygous loss-of-function variants in the Xq13.1-located NONO gene in patients were initially associated with an intellectual disability syndrome (MIM: 300967), with findings including macrocephaly, nonfamilial features, and thickened corpus callosum (Mircsof et al., 2015). Subsequently, four additional patients were described with these features and with left ventricular noncompaction (LVNC) cardiomyopathy (Reinstein et al., 2016; Scott et al., 2017). To date, five pathogenic NONO alterations have been reported, two of which were observed twice in unrelated patients.Notably, identical NONO variants were variably associated with LVNC. Here we report a patient with shared as well as additional features that confirm and expand the physical, functional, and cardiovascular phenotypes associated with NONO loss. | CLINICAL REPORTThis two-year-old boy at the time of testing was the first-born child of ...

Loss-of-function and hypomorphic ECHS1 variants are associated with mitochondrial short-chain enoyl-CoA hydratase deficiency, an inborn error of valine metabolism. We report an 8-year-old boy with developmental delay, ataxia, hemiplegia, and hearing loss with abnormalities in the basal ganglia. Biochemical studies were essentially normal except for a persistent mildly elevated CSF alanine. This patient demonstrates an intermediate phenotype between a Leigh-like, early-onset presentation and paroxysmal exercise-induced dyskinesia. Two novel ECHS1 variants (c.79T>G; p.Phe27Val and c.789_790del; p.Phe263fs) were identified via exome sequencing in the proband, and pathogenicity was confirmed by enzyme assay performed on patient fibroblasts. Neither of the ECHS1 variants detected in the child were present in the mother. However, due to nearby polymorphisms, it was possible to determine that p.Phe263fs occurred de novo on the maternal chromosome and that p.Phe27Val likely derived from the paternal chromosome. Nearby polymorphisms can help set phase of variants when only a single parent is available for testing or when an identified variant occurs de novo.