Deyle, David R.

Abstract Osteogenesis imperfecta (OI) is a heterogeneous group of inherited connective tissue disorders primarily caused by dominant mutations in COL1A1 or COL1A2 that impair type I procollagen folding and secretion. Misfolded collagen accumulates in the endoplasmic reticulum (ER), triggering ER stress and osteoblast dysfunction and bone fragility. Current pharmacologic therapy focuses on inhibiting bone resorption but has limited efficacy and does not address the underlying biology of the disease. The epigenetic regulator Polycomb-repressive complex 2 (PRC2) has emerged as an important regulator of bone formation. Genetic and pharmacologic disruption of PRC2 enhanced osteogenic differentiation in wild-type cells. Here we demonstrate that inhibition of the PRC2 through targeting its essential component embryonic ectoderm development (EED) enhances osteogenic differentiation, improves bone architecture in male Col1a2+/G610C OI mouse models, modulates the integrated stress response (ISR), and improves ER morphology in OI cells. These findings identify EED inhibition as a novel epigenetic strategy to restore collagen homeostasis and improve skeletal integrity in OI.

Abstract Introduction: Most rare disease patients (75 − 50%) undergoing genomic sequencing remain unsolved, often due to lack of information about variants identified. Data review over time can leverage novel information regarding disease-causing variants and genes, increasing this diagnostic yield. However, time and resource constraints have limited reanalysis of genetic data in clinical laboratories setting. We developed RENEW, (REannotation of NEgative WES/WGS) an automated reannotation procedure that uses relevant new information in on-line genetic databases to enable rapid review of genetic findings. Methods We tested RENEW in an unselected cohort of 1,066 undiagnosed cases from the Mayo Clinic Center for Individualized Medicine using new information in ClinVar, HGMD and OMIM between the date of previous analysis/testing and April of 2022. Results 5,741 variants prioritized by RENEW were rapidly reviewed by variant interpretation specialists. Mean analysis time was approximately 20 seconds per variant (32 hours total time). Reviewed cases were classified as: 879 (93.0%) undiagnosed, 63 (6.6%) putatively diagnosed, and 4 (0.4%) definitively diagnosed. Discussion New strategies are needed to enable efficient review of genomic findings in unsolved cases. We report on a fast and practical approach to address this need and improve overall diagnostic success in patient testing through a recurrent reannotation process.

The congenital heart surgeon frequently encounters patients with various genetic disorders requiring surgical intervention. Although the specifics of the genetics for these patients and their families lie in the purview of specialists in genetics, the surgeon is well-served to be familiar with aspects of specific syndromes that impact surgical management and perioperative care. This aids in counseling families in expectations for the hospital course and recovery as well as can impact intraoperative and surgical management. This review article summarizes key characteristics for the congenital heart surgeon to be familiar with for common genetic disorders as they help coordinate care.

Background Cardiovascular surgical outcomes reports are few for vascular type IV of Ehlers- Danlos Syndrome (vEDS) compared to non-vascular types I-III (nEDS). Methods To define cardiovascular surgical outcomes among adult patients (≥18 years) with EDS types, a review of our institution's in-house STS Adult Cardiac Surgery Database-compliant software and electronic medical records from Mayo Clinic (1993–2019) was performed. Outcomes were compared for vEDS patients and nEDS patients. Demographics, baseline characteristics, operative, in-hospital complications and follow-up vital status were analyzed. Results Over the study time frame, 48 EDS patients underwent surgery (mean age 52.6 ± 14.6 years; 48% females). Of these, 17 patients had vEDS and 31 patients had nEDS. Six patients (12.5%) underwent prior sternotomy. Urgent or emergent surgery was performed in 10 patients (20.8%). Aortic (vEDS 76.5% vs. nEDS 16.1%) and mitral procedures (vEDS 11.8% vs. nEDS 48.4%) were the two most common cardiovascular surgeries performed (p < .01 and p = .007, respectively). Cardiopulmonary bypass time (CPB) (165 ± 18 vs. 90 ± 13 min; p = .015) and aortic cross clamp times (140 ± 14 vs. 62 ± 10 min; p < .001) were longer for vEDS patients. There was 1 (2.1%) early and 7 (14.6%) late deaths; 6 among vEDS and 2 among nEDS patients. Survival at 5 (80% vs. 93%), 10 (45% vs. 84%) and 15 years (45% vs. 84%) was lower in patients with vEDS (p = .015 for each comparison). Conclusion Cardiovascular surgeries are significantly more complex with longer bypass and cross clamp times for type IV vEDS compared to nEDS patients. Reduced overall survival underscores the complexity and fragility of vEDS patients.

Abstract Career shadowing can be a valuable opportunity for individuals to experience the daily activities of a working professional. However, there is no published research regarding the impact of shadowing for individuals hoping to pursue a career as a genetic counselor (GC) (termed ‘shadowees’). Additionally, little is known about the impact of shadowing on practicing GCs, nor the value of shadowing in the application and admission process for genetic counseling graduate programs. For this study, three independent surveys were developed and sent to three stakeholder groups: shadowees in the Minnesota Genetic Counseling Experience Program, program directors within the Association of Genetic Counseling Program Directors, and members of the National Society of Genetic Counselors. Quantitative and qualitative analyses were performed on responses. The survey of shadowees ( n = 55) found that the majority believed that shadowing had either a ‘very’ or ‘somewhat positive’ impact on their decision to become a GC and on their application to a genetic counseling graduate program (81.8% and 91.3%, respectively). Of the participating program director respondents ( n = 43), the majority indicated that having shadowing experience was either ‘moderately’ or ‘extremely important’ in offering an interview or for acceptance into a graduate program (63% and 56%, respectively). While programs differ in evaluation of shadowing experiences, most program directors indicated that an applicant's ability to speak to their shadowing experience was the most important factor in admissions consideration (71%). Among the GCs surveyed ( n = 325), 69.2% have hosted shadowees; of these, 82.7% indicated that hosting a shadowee decreases their efficiency at work. Despite this drawback, the majority of respondents expressed a willingness and motivation to host shadowees to help the shadowee (64.8%) and to promote the genetic counseling profession (32.6%). These findings suggest the need for additional research and the development of resources for GCs to increase access of career shadowing.

Abstract Childhood dilated cardiomyopathy (DCM) is a leading cause of heart failure requiring cardiac transplantation and approximately 5% of cases result in sudden death. Knowledge of the underlying genetic cause can aid prognostication and clinical management and enables accurate recurrence risk counselling for the family. Here we used genomic sequencing to identify the causative genetic variant(s) in families with children affected by severe DCM. In an international collaborative effort facilitated by GeneMatcher, biallelic variants in PPP1R13L were identified in seven children with severe DCM from five unrelated families following exome or genome sequencing and inheritance‐based variant filtering. PPP1R13L encodes inhibitor of apoptosis‐stimulating protein of p53 protein (iASPP). In addition to roles in apoptosis, iASPP acts as a regulator of desmosomes and has been implicated in inflammatory pathways. DCM presented early (mean: 2 years 10 months; range: 3 months‐9 years) and was progressive, resulting in death (n = 3) or transplant (n = 3), with one child currently awaiting transplant. Genomic sequencing technologies are valuable for the identification of novel and emerging candidate genes. Biallelic variants in PPP1R13L were previously reported in a single consanguineous family with paediatric DCM. The identification here of a further five families now provides sufficient evidence to support a robust gene‐disease association between PPP1R13L and severe paediatric DCM. The PPP1R13L gene should be included in panel‐based genetic testing for paediatric DCM.

Skeletal development is controlled by epigenetic mechanisms that regulate chromatin compaction and suppress access to gene regulatory sequences. Post‐translational modifications in the N‐termini of histone 3 (H3), including tri‐methylated H3 lysine 9 (H3K9Me3) or lysine 27 (H3K27Me3) represent repressive chromatin marks that are recognized by a family of heterochromatin‐associated Chromobox (Cbx) proteins (i.e., Cbx1 to Cbx8). We show using RNA‐seq analysis that each of these Cbx isoforms is actively expressed in bone and osteoblasts with variable expression of distinct members (between 1 and 100 reads per million). The most prominently expressed Cbx member is Cbx3, which encodes a member of the heterochromatin protein 1 (HP1) family that interacts with H3K9me3. Cbx3 is known to be important for normal development while promoting neurogenesis, as well as renal and smooth muscle development. Therefore, we postulated that CBx3 may perform a similar role in osteoblastogenesis. We tested this hypothesis by both transient and stable knock‐down of Cbx3 by respectively siRNA or shRNA. RNA interference in MC3T3 osteoblasts effectively decreases Cbx3 mRNA levels by 2 to 5 fold, while increasing expression of bone‐related markers by RT‐qPCR (e.g., Alpl/alkaline phosphatase, Ibsp/bone sialoprotein, Bglap/osteocalcin, and Col1a1/Collagen Type I α1 chain). In addition, Cbx3 depletion increases mineral deposition as measured by Alizarin Red staining. Thus, Cbx3 normally appears to suppress osteoblastic differentiation, unlike its essential function in the neuronal differentiation. Because Cbx3 recognizes H3K9me3, we examined whether Cbx3 controls the levels of this histone mark. Loss of Cbx3 did not affect total H3K9me3 levels unless Cbx1 and Cbx5 were simultaneously depleted by siRNA. We propose that Cbx3 may suppress osteoblastogenesis by controlling select loci with H3K9me3 marks.