High-Throughput Genomics Identify Novel FBN1/2 Variants in Severe Neonatal Marfan Syndrome and Congenital Heart Defects.

Fibrillin-1 and fibrillin-2, encoded by FBN1 and FBN2, respectively, play significant roles in elastic fiber assembly, with pathogenic variants causing a diverse group of connective tissue disorders such as Marfan syndrome (MFS) and congenital contractural arachnodactyly (CCD). Different genomic variations may lead to heterogeneous phenotypic features and functional consequences. Recent high-throughput sequencing modalities have allowed detection of novel variants that may guide the care for patients and inform the genetic counseling for their families. We performed clinical phenotyping for two newborn infants with complex congenital heart defects. For genetic investigations, we employed next-generation sequencing strategies including whole-genome Single-Nucleotide Polymorphism (SNP) microarray for infant A with valvular insufficiency, aortic sinus dilatation, hydronephrosis, and dysmorphic features, and Trio whole-exome sequencing (WES) for infant B with dextro-transposition of the great arteries (D-TGA) and both parents. Infant A is a term male with neonatal marfanoid features, left-sided hydronephrosis, and complex congenital heart defects including tricuspid regurgitation, aortic sinus dilatation, patent foramen ovale, patent ductus arteriosus, mitral regurgitation, tricuspid regurgitation, aortic regurgitation, and pulmonary sinus dilatation. He developed severe persistent pulmonary hypertension and worsening acute hypercapnic hypoxemic respiratory failure, and subsequently expired on day of life (DOL) 10 after compassionate extubation. Cytogenomic whole-genome SNP microarray analysis revealed a deletion within the FBN1 gene spanning exons 7-30, which overlapped with the exon deletion hotspot region associated with neonatal Marfan syndrome. Infant B is a term male prenatally diagnosed with isolated D-TGA. He required balloon atrial septostomy on DOL 0 and subsequent atrial switch operation, atrial septal defect repair, and patent ductus arteriosus ligation on DOL 5. Trio-WES revealed compound heterozygous c.518C>T and c.8230T>G variants in the FBN2 gene. Zygosity analysis confirmed each of the variants was inherited from one of the parents who were healthy heterozygous carriers. Since his cardiac repair at birth, he has been growing and developing well without any further hospitalization. Our study highlights novel FBN1/FBN2 variants and signifies the phenotype-genotype association in two infants affected with complex congenital heart defects with and without dysmorphic features. These findings speak to the importance of next-generation high-throughput genomics for novel variant detection and the phenotypic variability associated with FBN1/FBN2 variants, particularly in the neonatal period, which may significantly impact clinical care and family counseling.

Anatomical Location of the Vesical Branches of the Inferior Hypogastric Plexus in Human Cadavers.

We have demonstrated in canines that somatic nerve transfer to vesical branches of the inferior hypogastric plexus (IHP) can be used for bladder reinnervation after spinal root injury. Yet, the complex anatomy of the IHP hinders the clinical application of this repair strategy. Here, using human cadavers, we clarify the spatial relationships of the vesical branches of the IHP and nearby pelvic ganglia, with the ureteral orifice of the bladder. Forty-four pelvic regions were examined in 30 human cadavers. Gross post-mortem and intra-operative approaches (open anterior abdominal, manual laparoscopic, and robot-assisted) were used. Nerve branch distances and diameters were measured after thorough visual inspection and gentle dissection, so as to not distort tissue. The IHP had between 1 to 4 vesical branches (2.33 ± 0.72, mean ± SD) with average diameters of 0.51 ± 0.06 mm. Vesical branches from the IHP arose from a grossly visible pelvic ganglion in 93% of cases (confirmed histologically). The pelvic ganglion was typically located 7.11 ± 6.11 mm posterolateral to the ureteral orifice in 69% of specimens. With this in-depth characterization, vesical branches from the IHP can be safely located both posterolateral to the ureteral orifice and emanating from a more proximal ganglionic enlargement during surgical procedures.

Nerve transfer for restoration of lower motor neuron-lesioned bladder, urethral and anal sphincter function. Part 4: Effectiveness of the motor reinnervation.

In pilot work, we showed that somatic nerve transfers can restore motor function in long-term decentralized dogs. We continue to explore the effectiveness of motor reinnervation in 30 female dogs. After anesthesia, 12 underwent bilateral transection of coccygeal and sacral (S) spinal roots, dorsal roots of lumbar (L)7, and hypogastric nerves. Twelve months postdecentralization, eight underwent transfer of obturator nerve branches to pelvic nerve vesical branches, and sciatic nerve branches to pudendal nerves, followed by 10 mo recovery (ObNT-ScNT Reinn). The remaining four were euthanized 18 mo postdecentralization (Decentralized). Results were compared with 18 Controls. Squat-and-void postures were tracked during awake cystometry. None showed squat-and-void postures during the decentralization phase. Seven of eight ObNT-ScNT Reinn began showing such postures by 6 mo postreinnervation; one showed a return of defecation postures. Retrograde dyes were injected into the bladder and urethra 3 wk before euthanasia, at which point, roots and transferred nerves were electrically stimulated to evaluate motor function. Upon L2-L6 root stimulation, five of eight ObNT-ScNT Reinn showed elevated detrusor pressure and four showed elevated urethral pressure, compared with L7-S3 root stimulation. After stimulation of sciatic-to-pudendal transferred nerves, three of eight ObNT-ScNT Reinn showed elevated urethral pressure; all showed elevated anal sphincter pressure. Retrogradely labeled neurons were observed in L2-L6 ventral horns (in laminae VI, VIII, and IX) of ObNT-ScNT Reinn versus Controls in which labeled neurons were observed in L7-S3 ventral horns (in lamina VII). This data supports the use of nerve transfer techniques for the restoration of bladder function.NEW & NOTEWORTHY This data supports the use of nerve transfer techniques for the restoration of bladder function.

Engineered neurogenesis in naïve adult rat cortex by Ngn2-mediated neuronal reprogramming of resident oligodendrocyte progenitor cells.

Adult tissue stem cells contribute to tissue homeostasis and repair but the long-lived neurons in the human adult cerebral cortex are not replaced, despite evidence for a limited regenerative response. However, the adult cortex contains a population of proliferating oligodendrocyte progenitor cells (OPCs). We examined the capacity of rat cortical OPCs to be re-specified to a neuronal lineage both in vitro and in vivo. Expressing the developmental transcription factor Neurogenin2 (Ngn2) in OPCs isolated from adult rat cortex resulted in their expression of early neuronal lineage markers and genes while downregulating expression of OPC markers and genes. Ngn2 induced progression through a neuronal lineage to express mature neuronal markers and functional activity as glutamatergic neurons. In vivo retroviral gene delivery of Ngn2 to naive adult rat cortex ensured restricted targeting to proliferating OPCs. Ngn2 expression in OPCs resulted in their lineage re-specification and transition through an immature neuronal morphology into mature pyramidal cortical neurons with spiny dendrites, axons, synaptic contacts, and subtype specification matching local cytoarchitecture. Lineage re-specification of rat cortical OPCs occurred without prior injury, demonstrating these glial progenitor cells need not be put into a reactive state to achieve lineage reprogramming. These results show it may be feasible to precisely engineer additional neurons directly in adult cerebral cortex for experimental study or potentially for therapeutic use to modify dysfunctional or damaged circuitry.

Elucidation of bioinformatic-guided high-prospect drug repositioning candidates for DMD via Swanson linking of target-focused latent knowledge from text-mined categorical metadata.

Duchenne Muscular Dystrophy (DMD)'s complex multi-system pathophysiology, coupled with the cost-prohibitive logistics of multi-year drug screening and follow-up, has hampered the pursuit of new therapeutic approaches. Here we conducted a systematic historical and text mining-based pilot feasibility study to explore the potential of established or previously tested drugs as prospective DMD therapeutic agents. Our approach utilized a Swanson linking-inspired method to uncover meaningful yet largely hidden deep semantic connections between pharmacologically significant DMD targets and drugs developed for unrelated diseases. Specifically, we focused on molecular target-based MeSH terms and categories as high-yield bioinformatic proxies, effectively tagging relevant literature with categorical metadata. To identify promising leads, we comprehensively assembled published reports from 2011 and sampling from subsequent years. We then determined the earliest year when distinct MeSH terms or category labels of the relevant cellular target were referenced in conjunction with the drug, as well as when the pertinent target itself was first conclusively identified as holding therapeutic value for DMD. By comparing the earliest year when the drug was identifiable as a DMD treatment candidate with that of the first actual report confirming this, we computed an Index of Delayed Discovery (IDD), which serves as a metric of Swanson-linked latent knowledge. Using these findings, we identified data from previously unlinked articles subsetted via MeSH-derived Swanson linking or from target classes within the DrugBank repository. This enabled us to identify new but untested high-prospect small-molecule candidates that are of particular interest in repurposing for DMD and warrant further investigations.

Full-length Isoform Sequencing for Resolving the Molecular Basis of Charcot-Marie-Tooth 2A.

Objectives: Transcript sequencing of patient-derived samples has been shown to improve the diagnostic yield for solving cases of suspected Mendelian conditions, yet the added benefit of full-length long-read transcript sequencing is largely unexplored. Methods: We applied short-read and full-length transcript sequencing and mitochondrial functional studies to a patient-derived fibroblast cell line from an individual with neuropathy that previously lacked a molecular diagnosis. Results: We identified an intronic homozygous MFN2 c.600-31T>G variant that disrupts the branch point critical for intron 6 splicing. Full-length long-read isoform complementary DNA (cDNA) sequencing after treatment with a nonsense-mediated mRNA decay (NMD) inhibitor revealed that this variant creates 5 distinct altered splicing transcripts. All 5 altered splicing transcripts have disrupted open reading frames and are subject to NMD. Furthermore, a patient-derived fibroblast line demonstrated abnormal lipid droplet formation, consistent with MFN2 dysfunction. Although correctly spliced full-length MFN2 transcripts are still produced, this branch point variant results in deficient MFN2 levels and autosomal recessive Charcot-Marie-Tooth disease, axonal, type 2A (CMT2A). Discussion: This case highlights the utility of full-length isoform sequencing for characterizing the molecular mechanism of undiagnosed rare diseases and expands our understanding of the genetic basis for CMT2A.

Transcriptomic analysis of paired healthy human skeletal muscles to identify modulators of disease severity in DMD.

Muscle damage and fibro-fatty replacement of skeletal muscles is a main pathologic feature of Duchenne muscular dystrophy (DMD) with more proximal muscles affected earlier and more distal affected later in the disease course, suggesting that different skeletal muscle groups possess distinctive characteristics that influence their susceptibility to disease. To explore transcriptomic factors driving differential gene expression and modulating DMD skeletal muscle severity, we characterized the transcriptome of vastus lateralis (VL), a more proximal and susceptible muscle, relative to tibialis anterior (TA), a more distal and protected muscle, in 15 healthy individuals using bulk RNA sequencing to identify gene expression differences that may mediate their relative susceptibility to damage with loss of dystrophin. Matching single nuclei RNA sequencing data was generated for 3 of the healthy individuals, to infer cell composition in the bulk RNA sequencing dataset and to improve mapping of differentially expressed genes to their cell source of expression. A total of 3,410 differentially expressed genes were identified and mapped to cell type using single nuclei RNA sequencing of muscle, including long non-coding RNAs and protein coding genes. There was an enrichment of genes involved in calcium release from the sarcoplasmic reticulum, particularly in the myofibers and these myofiber genes were higher in the VL. There was an enrichment of genes in "Collagen-Containing Extracellular Matrix" expressed by fibroblasts, endothelial, smooth muscle and pericytes, with most genes higher in the TA, as well as genes in "Regulation Of Apoptotic Process" expressed across all cell types. Previously reported genetic modifiers were also enriched within the differentially expressed genes. We also identify 6 genes with differential isoform usage between the VL and TA. Lastly, we integrate our findings with DMD RNA sequencing data from the TA, and identify "Collagen-Containing Extracellular Matrix" and "Negative Regulation Of Apoptotic Process" as differentially expressed between DMD compared to healthy. Collectively, these findings propose novel candidate mechanisms that may mediate differential muscle susceptibility in muscular dystrophies and provide new insight into potential therapeutic targets.

Nerve transfer for restoration of lower motor neuron-lesioned bladder, urethral, and anal sphincter function in a dog model. Part 3. nicotinic receptor characterization.

Very little is known about the physiological role of nicotinic receptors in canine bladders, although functional nicotinic receptors have been reported in bladders of many species. Utilizing in vitro methods, we evaluated nicotinic receptors mediating bladder function in dogs: control (9 female and 11 male normal controls, 5 sham operated), Decentralized (9 females, decentralized 6-21 mo), and obturator-to-pelvic nerve transfer reinnervated (ObNT-Reinn; 9 females; decentralized 9-13 mo, then reinnervated with 8-12 mo recovery). Muscle strips were collected, mucosa-denuded, and mounted in muscle baths before incubation with neurotransmitter antagonists, and contractions to the nicotinic receptor agonist epibatidine were determined. Strip response to epibatidine, expressed as percent potassium chloride, was similar (∼35% in controls, 30% in Decentralized, and 24% in ObNT-Reinn). Differentially, epibatidine responses in Decentralized and ObNT-Reinn bladder strips were lower than controls after tetrodotoxin (TTX, a sodium channel blocker that inhibits axonal action potentials). Yet, in all groups, epibatidine-induced strip contractions were similarly inhibited by mecamylamine and hexamethonium (ganglionic nicotinic receptor antagonists), SR 16584 (α3ß4 neuronal nicotinic receptor antagonist), atracurium and tubocurarine (neuromuscular nicotinic receptor antagonists), and atropine (muscarinic receptor antagonist), indicating that nicotinic receptors (particularly α3ß4 subtypes), neuromuscular and muscarinic receptors play roles in bladder contractility. In control bladder strips, since tetrodotoxin did not inhibit epibatidine contractions, nicotinic receptors are likely located on nerve terminals. The tetrodotoxin inhibition of epibatidine-induced contractions in Decentralized and ObNT-Reinn suggests a relocation of nicotinic receptors from nerve terminals to more distant axonal sites, perhaps as a compensatory mechanism to recover bladder function.

Point of care ultrasound: Current and future directions for Acute Medicine.

Point of care ultrasound (POCUS) represents an exciting tool for current and future acute care practitioners. POCUS has come a long way in a short space of time and its widespread implementation may well be one of the biggest changes seen in acute medicine across the next decade. This narrative review explores the increasing evidence base for the accuracy of POCUS use in various acute scenarios, whilst also addressing current gaps in the evidence and areas for potential future POCUS development.

Selective Tibial Neurotomy Outcomes for Spastic Equinovarus Foot: Patient Expectations and Functional Assessment.

BACKGROUND: Spastic equinovarus foot (SEF) is a common dysfunctional foot posture after stroke that impairs balance and mobility. Selective tibial neurotomy (STN) is a simple but underutilized surgical option that can effectively address critical aspects of SEF and thereby provide enduring quality of life gains. There are few studies that examine both functional outcomes and patient satisfaction with this treatment option. OBJECTIVE: To elucidate the patient goals that motivated their decision to undergo the procedure and compare subjective and objective changes in balance and functional mobility as a consequence of surgery. METHODS: Thirteen patients with problematic SEF who had previously failed conservative measures were treated with STN. Preoperative and postoperative (on average 6 months) assessments evaluated gait quality and functional mobility. In addition, a custom survey was conducted to investigate patient perspectives on STN intervention. RESULTS: The survey showed that participants who opted for STN were dissatisfied with their previous spasticity management. The most common preoperative expectation for STN treatment was to improve walking, followed by improving balance, brace comfort, pain, and tone. Postoperatively, participants rated the improvement in their expectations and were, on average, 71 on a 100-point scale, indicating high satisfaction. The gait quality, assessed with the Gait Intervention and Assessment Tool, improved significantly between preoperative and postoperative assessment (M = -4.1, P = .01) with a higher average difference in stance of -3.3 than in swing -0.5. Improvement in both gait endurance (M = 36 m, P = .01) and self-selected gait speed (M = .12 m/s, P = .03) was statistically significant. Finally, static balance (M = 5.0, P = .03) and dynamic balance (M = 3.5, P = .02) were also significantly improved. CONCLUSION: STN improved gait quality and functional mobility and was associated with high satisfaction in patients with SEF.

Variability in Celiac Serology Testing by Provider Type: A Single-Center Experience.

To evaluate the ordering practices of celiac disease (CD) serologies by providers at a tertiary, academic, Children's Hospital and compare them to guidelines and best practices. Methods: We analyzed celiac serologies ordered in 2018 by provider type (pediatric gastrointestinal (GI) specialists, primary care providers (PCPs), and nonpediatric GI specialists), and identified causes for variability and nonadherence. Results: The antitissue transglutaminase antibody (tTG) IgA was ordered (n = 2504) most frequently by gastroenterologists (43%), endocrinologists (22%), and other (35%). Total IgA was ordered with tTG IgA for screening purposes in 81% of overall cases, but endocrinologists ordered it only 49% of the time. The tTG IgG was ordered infrequently (1.9%) compared with tTG IgA. Antideaminated gliadin peptide (DGP) IgA/IgG levels were also infrequently ordered (5.4%) compared with tTG IgA. The antiendomysial antibody was ordered sparingly (0.9%) compared with tTG IgA, but appropriately by providers with expertise in CD, similar to ordering for celiac genetics (0.8%). Of the celiac genetic tests, 15% were ordered in error. The positivity rate of the tTG IgA ordered by PCPs was 4.4%. Conclusions: The tTG IgA was appropriately ordered by all types of providers. Endocrinologists inconsistently ordered total IgA levels with screening labs. DGP IgA/IgG tests were not commonly ordered but were inappropriately ordered by one provider. The low number of ordered antiendomysial antibody and celiac genetic tests suggests under-utilization of the nonbiopsy approach. The positive yield of tTG IgA ordered by PCPs was higher compared with previous studies.

RAF1 deficiency causes a lethal syndrome that underscores RTK signaling during embryogenesis.

Somatic and germline gain-of-function point mutations in RAF, one of the first oncogenes to be discovered in humans, delineate a group of tumor-prone syndromes known as the RASopathies. In this study, we document the first human phenotype resulting from the germline loss-of-function of the proto-oncogene RAF1 (a.k.a. CRAF). In a consanguineous family, we uncovered a homozygous p.Thr543Met variant segregating with a neonatal lethal syndrome with cutaneous, craniofacial, cardiac, and limb anomalies. Structure-based prediction and functional tests using human knock-in cells showed that threonine 543 is essential to: (i) ensure RAF1's stability and phosphorylation, (ii) maintain its kinase activity toward substrates of the MAPK pathway, and (iii) protect from stress-induced apoptosis mediated by ASK1. In Xenopus embryos, mutant RAF1T543M failed to phenocopy the effects of normal and overactive FGF/MAPK signaling, confirming its hypomorphic activity. Collectively, our data disclose the genetic and molecular etiology of a novel lethal syndrome with progeroid features, highlighting the importance of RTK signaling for human development and homeostasis.

De novo variants in MRTFB have gain-of-function activity in Drosophila and are associated with a novel neurodevelopmental phenotype with dysmorphic features.

PURPOSE: Myocardin-related transcription factor B (MRTFB) is an important transcriptional regulator, which promotes the activity of an estimated 300 genes but is not known to underlie a Mendelian disorder. METHODS: Probands were identified through the efforts of the Undiagnosed Disease Network. Because the MRTFB protein is highly conserved between vertebrate and invertebrate model organisms, we generated a humanized Drosophila model expressing the human MRTFB protein in the same spatial and temporal pattern as the fly gene. Actin binding assays were used to validate the effect of the variants on MRTFB. RESULTS: Here, we report 2 pediatric probands with de novo variants in MRTFB (p.R104G and p.A91P) and mild dysmorphic features, intellectual disability, global developmental delays, speech apraxia, and impulse control issues. Expression of the variants within wing tissues of a fruit fly model resulted in changes in wing morphology. The MRTFBR104G and MRTFBA91P variants also display a decreased level of actin binding within critical RPEL domains, resulting in increased transcriptional activity and changes in the organization of the actin cytoskeleton. CONCLUSION: The MRTFBR104G and MRTFBA91P variants affect the regulation of the protein and underlie a novel neurodevelopmental disorder. Overall, our data suggest that these variants act as a gain of function.

SATB1 Chromatin Loops Regulate Megakaryocyte/Erythroid Progenitor Expansion by Facilitating HSP70 and GATA1 Induction.

Diamond Blackfan anemia (DBA) is an inherited bone marrow failure syndrome associated with severe anemia, congenital malformations, and an increased risk of developing cancer. The chromatin-binding special AT-rich sequence-binding protein-1 (SATB1) is downregulated in megakaryocyte/erythroid progenitors (MEPs) in patients and cell models of DBA, leading to a reduction in MEP expansion. Here we demonstrate that SATB1 expression is required for the upregulation of the critical erythroid factors heat shock protein 70 (HSP70) and GATA1 which accompanies MEP differentiation. SATB1 binding to specific sites surrounding the HSP70 genes promotes chromatin loops that are required for the induction of HSP70, which, in turn, promotes GATA1 induction. This demonstrates that SATB1, although gradually downregulated during myelopoiesis, maintains a biological function in early myeloid progenitors.

Pain management following dental trauma and surgical procedures.

Surgical procedures and post-traumatic management of dental patients require effective pain management during treatment, but being considerably more invasive than conservative treatments, pain management is required into the postoperative period. Clinical trials on pain intensity following dental surgical procedures (e.g., 3rd molar extraction, implant placement, periodontal, and endodontic surgery) have shown that pain is most intense approximately 5-6 h after completion of the procedure, reaching its peak levels during the first postoperative day. Greatest consumption of analgesics occurs during the first 48-72 h after 3rd molar extraction. For the management of perioperative pain associated with either conservative or surgical dental treatment, the local anesthetics articaine, lidocaine, mepivacaine, and prilocaine are preferred. These drugs, with a vasoconstrictor, provide a rapid onset and a duration of pulpal anesthesia adequate to complete most dental and surgical procedures painlessly. For management of post-traumatic and postsurgical pain, bupivacaine-administered by an appropriate nerve block-near the conclusion of a surgical procedure, can provide the patient with a pain-free period of up to 12 h. Nonsteroidal anti-inflammatory drugs represent the most effective drugs for the management of dental postsurgical pain. NSAIDs, as a group in therapeutic doses, have numbers needed to treat (NNTs) ranging from 2 to 3, while opioid analgesics do not approach those for NSAIDs. A protocol for management of pain following surgical procedures and traumatic injuries is discussed in this paper and includes preemptive NSAID; perioperative pain management; postoperative pain management-local anesthesia; postoperative pain management-analgesics; postoperative telephone call.

The Use of Contrast May Improve Aortic Valve Assessment During Transesophageal Echocardiography.

OBJECTIVES: The Doppler profile that quantifies the degree of aortic stenosis is essential, as an inaccurate measurement can alter the surgical plan. The authors aimed to examine the level of agreement between the contrast and noncontrast methods of aortic valve sizing during intraoperative transesophageal echocardiography (TEE). SETTING: At a tertiary hospital. PARTICIPANTS: A total of 30 patients undergoing surgical aortic valve replacement for a stenotic valve. INTERVENTIONS: Perflutren lipid microsphere contrast injection. MEASUREMENTS AND MAIN RESULTS: The authors reviewed Doppler studies of 30 consecutive patients undergoing aortic valve replacement in whom a contrast agent was given (perflutren lipid microsphere). They measured the peak and/or mean aortic valve gradients and velocity time integral readings through the left ventricular outflow tract (LVOT), and the aortic valve before and after administering the contrast agent. The aortic valve area was then calculated using both methods. Paired t tests and Bland-Altman analyses were used to examine the bias and the level of agreement between the 2 processes. By not using a contrast agent, the aortic valve area was overestimated by 0.26 cm2 compared to those measured by transthoracic echocardiography (TTE) (p < 0.001). Using a contrast agent, TEE measurements were comparable to those obtained by TTE. Moreover, the peak and mean aortic valve gradients were underestimated by 19 and 11 mmHg, respectively (p value <0.001). Adding contrast did not affect the pulse-wave Doppler readings of the V1 velocity of the LVOT. CONCLUSION: This discrepancy is significant and could affect the decision to replace the aortic valve. When evaluating the aortic valve with TEE, the authors recommend using a contrast agent to improve the Doppler profile and to obtain a more accurate measurement of the aortic valve area.

Full-length isoform sequencing for resolving the molecular basis of Charcot-Marie-Tooth 2A.

Objectives: Transcript sequencing of patient derived samples has been shown to improve the diagnostic yield for solving cases of likely Mendelian disorders, yet the added benefit of full-length long-read transcript sequencing is largely unexplored. Methods: We applied short-read and full-length isoform cDNA sequencing and mitochondrial functional studies to a patient-derived fibroblast cell line from an individual with neuropathy that previously lacked a molecular diagnosis. Results: We identified an intronic homozygous MFN2 c.600-31T>G variant that disrupts a branch point critical for intron 6 spicing. Full-length long-read isoform cDNA sequencing after treatment with a nonsense-mediated mRNA decay (NMD) inhibitor revealed that this variant creates five distinct altered splicing transcripts. All five altered splicing transcripts have disrupted open reading frames and are subject to NMD. Furthermore, a patient-derived fibroblast line demonstrated abnormal lipid droplet formation, consistent with MFN2 dysfunction. Although correctly spliced full-length MFN2 transcripts are still produced, this branch point variant results in deficient MFN2 protein levels and autosomal recessive Charcot-Marie-Tooth disease, axonal, type 2A (CMT2A). Discussion: This case highlights the utility of full-length isoform sequencing for characterizing the molecular mechanism of undiagnosed rare diseases and expands our understanding of the genetic basis for CMT2A.

"Play with Me, Darling!" Testing the Associations between Adult Playfulness and Indicators of Sexuality.

Previous studies have shown that individual differences in adult playfulness are important in interpersonal relationships. However, there is a lack of research on the role of playfulness in human sexuality. Using three studies with four independently collected samples (Ntotal = 1,124) we tested the differential relations between global playfulness and four facets of playfulness (Other-directed, Lighthearted, Intellectual, Whimsical; OLIW) with broad ("Sexy Seven") and narrow (sociosexuality, sexual sensation seeking, and sexual compulsivity) sexuality-related personality traits and sadomasochistic sexual practices (BDSM). Our main findings were: (1) Each of the Sexy Seven traits was related to global playfulness or at least one playfulness facet while only Whimsical playfulness (liking odd and/or unusual things, persons, or activities) was related to each Sexy Seven trait; (2) Sexual sensation seeking related to playfulness with small effect sizes (f2 ≤ 0.11), Whimsical playfulness positively related to narrow traits of sexuality; and (3) those engaging in BDSM were more playful than non-practitioners. The findings support the notion that playfulness (particularly Whimsical playfulness) relates to sexuality-related personality traits and sadomasochistic practices may be one way of expressing adult playfulness.

Genetic variants in DDX53 contribute to Autism Spectrum Disorder associated with the Xp22.11 locus.

Autism Spectrum Disorder (ASD) exhibits an ~4:1 male-to-female sex bias and is characterized by early-onset impairment of social/communication skills, restricted interests, and stereotyped behaviors. Disruption of the Xp22.11 locus has been associated with ASD in males. This locus includes the three-exon PTCHD1 gene, an adjacent multi-isoform long noncoding RNA (lncRNA) named PTCHD1-AS (spanning ~1Mb), and a poorly characterized single-exon RNA helicase named DDX53 that is intronic to PTCHD1-AS. While the relationship between PTCHD1/PTCHD1-AS and ASD is being studied, the role of DDX53 has not been examined, in part because there is no apparent functional murine orthologue. Through clinical testing, here, we identified 6 males and 1 female with ASD from 6 unrelated families carrying rare, predicted-damaging or loss-of-function variants in DDX53. Then, we examined databases, including the Autism Speaks MSSNG and Simons Foundation Autism Research Initiative, as well as population controls. We identified 24 additional individuals with ASD harboring rare, damaging DDX53 variations, including the same variants detected in two families from the original clinical analysis. In this extended cohort of 31 participants with ASD (28 male, 3 female), we identified 25 mostly maternally-inherited variations in DDX53, including 18 missense changes, 2 truncating variants, 2 in-frame variants, 2 deletions in the 3' UTR and 1 copy number deletion. Our findings in humans support a direct link between DDX53 and ASD, which will be important in clinical genetic testing. These same autism-related findings, coupled with the observation that a functional orthologous gene is not found in mouse, may also influence the design and interpretation of murine-modelling of ASD.

INTS13 variants causing a recessive developmental ciliopathy disrupt assembly of the Integrator complex.

Oral-facial-digital (OFD) syndromes are a heterogeneous group of congenital disorders characterized by malformations of the face and oral cavity, and digit anomalies. Mutations within 12 cilia-related genes have been identified that cause several types of OFD, suggesting that OFDs constitute a subgroup of developmental ciliopathies. Through homozygosity mapping and exome sequencing of two families with variable OFD type 2, we identified distinct germline variants in INTS13, a subunit of the Integrator complex. This multiprotein complex associates with RNA Polymerase II and cleaves nascent RNA to modulate gene expression. We determined that INTS13 utilizes its C-terminus to bind the Integrator cleavage module, which is disrupted by the identified germline variants p.S652L and p.K668Nfs*9. Depletion of INTS13 disrupts ciliogenesis in human cultured cells and causes dysregulation of a broad collection of ciliary genes. Accordingly, its knockdown in Xenopus embryos leads to motile cilia anomalies. Altogether, we show that mutations in INTS13 cause an autosomal recessive ciliopathy, which reveals key interactions between components of the Integrator complex.