I n an extended twin study we estimated the heritability of fasting HbA1c and blood glucose levels. Blood glucose was assessed in different settings (at home and in the clinic). We tested whether the genetic factors influencing fasting blood glucose levels overlapped with those influencing HbA1c and whether the same genetic factors were expressed across different settings. Fasting blood glucose was measured at home and during two visits to the clinic in 77 healthy families with same-sex twins and siblings, aged 20 to 45 years. HbA1c was measured during the first clinic visit. A 4-variate genetic structural equation model was used that estimated the heritability of each trait and the genetic correlations among traits. Heritability explained 75% of the variance in HbA1c. The heritability of fasting blood glucose was estimated at 66% at home and lower in the clinic (57% and 38%). Fasting blood glucose levels were significantly correlated across settings (0.34 < r < 0.54), mostly due to a common set of genes that explained between 53% and 95% of these correlations. Correlations between HbA1c and fasting blood glucoses were low (0.11 < r < 0.23) and genetic factors influencing HbA1c and fasting glucose were uncorrelated. These results suggest that in healthy adults the genes influencing HbA1c and fasting blood glucose reflect different aspects of the glucose metabolism. As a consequence these two glycemic parameters can not be used interchangeably in diagnostic procedures or in studies attempting to find genes for diabetes. Both contribute unique (genetic) information.

Background: Fibrodysplasia ossificans progressiva (FOP), an ultra-rare disorder caused by mutations in the gene encoding activin A receptor type 1 (ACVR1), is characterized by painful flare-ups and cumulative heterotopic ossification (HO). Garetosmab, a fully-human monoclonal antibody blocking activin A, prevents HO in FOP mice. Methods: LUMINA-1 (NCT03188666) was a phase 2, multi-center, randomized, double-blind, placebo-controlled study evaluating the safety, tolerability, and effects on HO of intravenous (IV) garetosmab 10 mg/kg every 4 weeks (Q4W). Adult patients with FOP were randomized to garetosmab or placebo for 28 weeks (Period 1), followed by an open-label period (Period 2). After Period 2, patients were allowed to stay on garetosmab in an open-label extension. For Period 1, primary endpoints were HO total lesion activity (HO-TLA) by 18F-sodium fluoride positron emission tomography (18F-NaF PET) and HO total lesion volume by computed tomography (CT). The Period 2 primary endpoint compared the number of new lesions in Period 2 versus Period 1. The safety primary endpoint was incidence and severity of TEAEs through the end of the Period 1 at week 28. Findings: Patients (n=44) were randomized to garetosmab (n=20) or placebo (n=24). In Period_1, there was a trend for garetosmab to decrease HO-TLA versus placebo (24.6%; P=0.07), primarily driven by near complete prevention of new lesions (97% decrease by 18F-NaF PET, post-hoc P=0.009; 90% relative reduction by CT, post-hoc P=0.017); flare-ups were significantly reduced (P=0.0005). For placebo patients transitioning to garetosmab in Period 2, no patients developed new HO lesions (0% in Period 2 versus 40.9% in Period_1; P=0.0027) by CT. All 44 patients met primary safety endpoint of at least one TEAE during Period 1. Garetosmab was associated with more adverse events than placebo: mild recurrent epistaxis, madarosis, and skin/soft tissue infections. Overall, the AEs were predominantly mild in severity, with no effect on patients' ability to receive garetosmab. Five deaths (5/44; 11.4%) occurred either in Period 2 or the open-label extension. The deaths were associated with baseline disease severity in some, pre-existing comorbidities in others and occurred following 8-16 doses (median: 15) of garetosmab in the open label/follow-up periods. Interpretation: Garetosmab reduced flare-ups and prevented new HO lesions in FOP patients. Although side effects were mild to moderate, there were a relatively high number of deaths for a small study; the deaths were not related to epistaxis and considered unlikely to be related to garetosmab.

Backgtound Deep venous thrombosis is a common disease, with genetic and acquired nsk factors Many patients have a history of minor events (short penods of iramobihsaüon such äs prolonged travel, short illness. ramor surgery or injunes) before onset of venous thrombosis However. the role of these mmor events has received httle formal study Also, we do not know how mmor events might mteract with the presence of genetic prothrombotic defects (factor V Leiden mutation factor II mutation, protein C S and antithrombin deficiency) Patients and Methods On the basis of case-control data from a thrombosis Service m the Netherlands we added a follow-up penod for a casecross-over analysis of minor events äs nsk factors, and a case only analysis toi the mteraction with factor V Leiden A total of 187 patients with first. objectively diagnosed venous thrombosis of the legs, aged 15-70, without underlymg malignanues and without major acquired nsk factors entered the study Tor the analy sis of minor events in the case-cross-over analysis we used a matched odds ratio, m the case only analysis we used the multiphcative s\nergy mdex Results In 32 6% ot the 187 patients with deep venous thrombosis who did not have major acquired nsk tactors, mmor events were the only external nsk factors Minor events mcreased the nsk of thrombosis about 3-fold äs estimated m the case-cross-over analysis (odds ratio 2 9, 95% confidence interval l 5-5 4) The synergy mdex between minor events and factor V Leiden mutation m the case-only analysis was 0 7 (95% confidence interval 03-15) Therefore, persons with factor V Leiden mutation who expenence a minor event will have an estimated nsk mcrease of about 17-fold. which exceeds the sum of the mdividual nsk factors Condusions Mmor events are hkelv to play an important role m the development of deep venous thrombosis, especially m the presence of genetic prothrombotic conditions

Fibrodysplasia ossificans progressiva (FOP), sometimes known as myositis ossificans progressiva, is an ultra-rare disease in which bone is formed in muscular tissue, tendons and ligaments. This is known as heterotopic ossification (HO). FOP is caused by a heterozygous mutation in the highly conserved ACVR1/ALK2 gene which affects about 1 in 1.5–2 million individuals. At birth, patients with the predominant R206H mutation only exhibit a bilateral hallux valgus. During childhood, heterotopic bone formation develops in a typical pattern, affecting the axial muscles first before appendicular body parts are involved. HO can start spontaneously but is often elicited by soft tissue trauma or medical procedures. After soft tissue injury, an inflammatory process called a flare-up can start, followed by the formation of HO. HO leads to a limited range of motion, culminating in complete ankylosis of nearly all joints. As a result of HO surrounding the thorax, patients often suffer from thoracic insufficiency syndrome (TIS). TIS is the most common cause of a limited life expectancy for FOP patients, with a median life expectancy of 56 years. Management is focused on preventing soft-tissue injury that can provoke flare-ups. This includes prevention of iatrogenic damage by biopsies, intramuscular injections and surgery. Anti-inflammatory medication is often started when a flare-up occurs but has a poor basis of evidence. Several forms of potential treatment for FOP are being researched in clinical trials. Progression of the disease is monitored using CT and 18F-NaF PET/CT combined with functional assessments. Patients are regularly evaluated for frequently occurring complications such as restrictive lung disease. Here, we review the current management, monitoring and treatment of FOP.

Osteogenesis Imperfecta (OI) is a complex disease caused by genetic alterations in production of collagen type I, and collagen-related proteins. Bone fragility is the most common patient issue, but extraskeletal complications also present an adverse factor in the quality of life and prognosis of patients with OI. However, still little is known about the morbidity and mortality of these patients. The objective of this paper is to determine and describe to what extent OI impacts patients’ life in terms of hospitalization and complications describing the incidence and prevalence of the Dutch cohort of OI patients and the characteristics of their hospital admissions. Information regarding OI patients and their hospital admission was extracted from the Statistics Netherlands Database and matched to the OI Genetics Database of Amsterdam UMC. Hospital admission data was available for 674 OI patients. This OI nationwide registry study shows that the life expectancy of OI patients is adversely affected by the disease. The median annual incidence risk of OI between 1992 and 2019 was 6.5 per 100,000 live births. Furthermore, patients with OI had a 2.9 times higher hospitalization rate compared to the general Dutch population. The highest hospitalization rate ratio of 8.4 was reported in the patient group between 0 and 19 years old. OI type and severity had impact on extraskeletal manifestations, which play a key role in the numerous hospital admissions. More awareness about the impact of OI on patients’ life is needed to improve and implement prevention and follow-up guidelines.

Fibrodysplasia ossificans progressiva (FOP) is a rare and devastating genetic disease, in which soft connective tissue is converted into heterotopic bone through an endochondral ossification process. Patients succumb early as they gradually become trapped in a second skeleton of heterotopic bone. Although the underlying genetic defect is long known, the inherent complexity of the disease has hindered the discovery of effective preventions and treatments. New developments in the gene therapy field have motivated its consideration as an attractive therapeutic option for FOP. However, the immune system's role in FOP activation and the as-yet unknown primary causative cell, are crucial issues which must be taken into account in the therapy design. While gene therapy offers a potential therapeutic solution, more knowledge about FOP is needed to enable its optimal and safe application.

This is a retrospective review of two adult siblings with osteogenesis imperfecta (OI) type III (according to Sillence classification), who sustained a spontaneous femoral neck fracture and subsequent nonunion. The diagnosis of OI in these two patients was made based on clinical, radiological and genetic findings. The fracture was most likely caused by femoroacetabular impingement secondary to OI induced acetabular protrusio. A valgus osteotomy according to Pauwels'principles and fixation of the osteotomy and nonunion with a locking plate resulted in healing despite compromised bone quality and limited bone stock. Long-term follow up (4.5 years and 6.5 years, respectively) is provided.When treating this difficult problem, improving the mechanobiological environment and decreasing the femoroacetabular impingement by a Pauwels type osteotomy should be considered.

Inherited bone disorders account for about 10% of documented Mendelian disorders and are associated with high financial burden. Their study requires osteoblasts which play a critical role in regulating the development and maintenance of bone tissue. However, bone tissue is not always available from patients. We developed a highly efficient platelet lysate-based approach to directly transdifferentiate skin-derived human fibroblasts to osteoblast-like cells. We extensively characterized our in vitro model by examining the expression of osteoblast-specific markers during the transdifferentiation process both at the mRNA and protein level. The transdifferentiated osteoblast-like cells showed significantly increased expression of a panel of osteogenic markers. Mineral deposition and ALP activity were also shown, confirming their osteogenic properties. RNA-seq analysis allowed the global study of changes in the transcriptome of the transdifferentiated cells. The transdifferentiated cells clustered separately from the primary fibroblasts with regard to the significantly upregulated genes indicating a distinct transcriptome profile; transdifferentiated osteoblasts also showed significant enrichment in gene expression related to skeletal development and bone mineralization. Our presented in vitro model may potentially contribute to the prospect of studying osteoblast-dependent disorders in patient-derived cells.