Role of CAMK2D in neurodevelopment and associated conditions

The calcium/calmodulin-dependent protein kinase type 2 (CAMK2) family consists of four different isozymes, encoded by four different genes-CAMK2A, CAMK2B, CAMK2G, and CAMK2D-of which the first three have been associated recently with neurodevelopmental disorders. CAMK2D is one of the major CAMK2 proteins expressed in the heart and has been associated with cardiac anomalies. Although this CAMK2 isoform is also known to be one of the major CAMK2 subtypes expressed during early brain development, it has never been linked with neurodevelopmental disorders until now. Here we show that CAMK2D plays an important role in neurodevelopment not only in mice but also in humans. We identified eight individuals harboring heterozygous variants in CAMK2D who display symptoms of intellectual disability, delayed speech, behavioral problems, and dilated cardiomyopathy. The majority of the variants tested lead to a gain of function (GoF), which appears to cause both neurological problems and dilated cardiomyopathy. In contrast, loss-of-function (LoF) variants appear to induce only neurological symptoms. Together, we describe a cohort of individuals with neurodevelopmental disorders and cardiac anomalies, harboring pathogenic variants in CAMK2D, confirming an important role for the CAMK2D isozyme in both heart and brain function.

Interstitial lung disease and pancreatic exocrine insufficiency in CADDS: Phenotypic expansion and literature review

Contiguous ABCD1/ DXS1357E deletion syndrome (CADDS) is a rare deletion syndrome involving two contiguous genes on Xq28, ABCD1 and BCAP31 (formerly known as DXS1357E). Only nine individuals with this diagnosis have been reported in the medical literature to date. Intragenic loss-of-function variants in BCAP31 cause the deafness, dystonia, and cerebral hypomyelination syndrome (DDCH). Isolated pathogenic intragenic variants in ABCD1 are associated with the most common peroxisomal disorder, X-linked adrenoleukodystrophy (X-ALD), a single transporter deficiency, which in its more severe cerebral form is characterised by childhood-onset neurodegeneration and high levels of very-long-chain fatty acids (VLCFA). While increased VLCFA levels also feature in CADDS, the few patients described to date all presented as neonates with a severe phenotype. Here we report a tenth individual with CADDS, a male infant with dysmorphic facial features who was diagnosed through ultra-rapid whole genome sequencing (WGS) in the setting of persistent cholestatic liver disease, sensorineural hearing loss, hypotonia and growth failure and developmental delay. Biochemical studies showed elevated VLCFA and mildly reduced plasmalogens. He died at 7 months having developed pancreatic exocrine deficiency and interstitial lung disease, two features we propose to be possible extensions to the CADDS phenotype. We also review the genetic, phenotypic, and biochemical features in previously reported individuals with CADDS.

Decreased peroxisome proliferator-activated receptor gamma expression levels in pericoronary adipose tissue adjacent to atherosclerotic plaque compared to lesion-free coronary arteries

Background

Pericoronary adipose tissue (PCAT) regulates arterial homeostasis, is considered to act in paracrine manner, and plays a role in the pathogenesis of atherosclerosis. The nuclear receptor Peroxisome Proliferator-Activated receptor gamma (PPARγ) is a key regulator of adipogenesis, and alterations of its function are associated with different pathological processes related to metabolic syndrome and inflammatory response.

Purpose

To investigate whether the PCAT surrounding coronary occlusive atherosclerotic lesions shows specific PPARγ expression pattern compared to PCAT surrounding plaque-free segments

Methods

We enrolled 47 patients (32 men, aged 68±12 years old) with 3-vessel coronary artery disease (CAD) who underwent elective coronary bypass surgery. A control group of 10 age- and sex-matched patients with severe valvular disease who underwent aortic or mitral valve replacement was also included (8 men, aged 67±15 years old). PCAT samples were received from all participants. In patients with CAD, the PCAT was harvested from two sites: adjacent to an occlusive atherosclerotic coronary lesion, and a plaque-free segment. PPARγ expression levels in PCAT cells were quantified by real-time reverse transcription polymerase chain reaction.

Results

PCAT analysis showed a significant downregulation of PPARγ expression levels in CAD compared to non-CAD patients (45±19 versus 93±15, p=0.01). In addition, PPARγ levels showed significantly lower expression in PCAT from around atherosclerotic plaque compared to lesion-free sites (31±12 versus 45±19, p=0.04). Notably, the expression of PPARγ from atherosclerotic plaque showed robust negative correlations with BMI (r=−0.47, p=0.001).

Conclusions

PPARγ in PCAT surrounding coronary occlusive atherosclerotic lesions are significantly downregulated and their levels are associated with patients' BMI. Our study opens new perspectives in the pathophysiologic role of PCAT in atherosclerotic complications of diabetes and should be further investigated.

Funding Acknowledgement

Type of funding sources: None.

Differences in microRNA expression in pericoronary tissue adjacent to atherosclerotic plaque and from lesion-free coronary artery

Background

Pericoronary adipose tissue (PCAT) plays a key role in the pathogenesis of atherosclerosis. PCAT is a source of microRNAs (miRs) that acts as messengers for intercellular communication. In this study, we investigated whether the PCAT surrounding coronary occlusive atherosclerotic lesions shows specific miR expression patterns compared to PCAT surrounding plaque-free segments.

Purpose

To evaluate the expression of miRs that are known to be implicated in the pathophysiology of atherosclerosis.

Methods

We included 49 patients (38 men, age 65±9 years) with 3-vessel coronary artery disease, who underwent elective coronary bypass surgery. The PCAT was harvested from two sites: adjacent to an occlusive atherosclerotic coronary lesion, and a plaque-free segment. miR-133a, miR-21, miR-26b, miR-9 and miR-143 levels in PCAT cells were quantified by real-time reverse transcription polymerase chain reaction.

Results

miR-26b, miR-21 and miR-143 showed significantly greater expression in PCAT samples taken from around atheromatous plaque (154±295 versus 37±96, p=0.014, for miR-26b; 122±265 versus 29±79, p=0.014, for miR-21; and 181±356 versus 31±50, p=0.03, for miR-143) (Figure 1). In addition, the expression of miR-143, miR-26b and miR-21 in PCAT from atherosclerotic plaque showed robust positive correlations with body.mass index (r=0.451, p=0.001, r=0.41, p=0.03 and r=0.416, p=0.003 respectively),

Conclusions

Analysis of PCAT located in proximity to atherosclerotic plaque showed a different pattern of miR expression compared to PCAT in a plaque-free segment. Our findings open new perspectives for the role of PCAT in the pathophysiological mechanisms of atherosclerotic disease and should be further investigated.

Funding Acknowledgement

Type of funding sources: None.

Artificial intelligence-based opportunistic screening for the detection of arterial hypertension through ECG signals

Background

Hypertension is a major risk factor for cardiovascular disease (CVD) which often escapes the diagnosis or should be confirmed by several office visits. The electrocardiogram (ECG) is one of the most widely used diagnostic tools and could be of paramount importance in patients' initial evaluation.

Purpose

To detect whether a person is hypertensive using features from the ECG, as well as basic anthropometric features such as age, sex, and body mass index (BMI).

Methods

We used machine learning (ML) techniques based features derived from the electrocardiogram for detecting hypertension in a population without CVD. We enrolled 1091 subjects who were classified into hypertensive and normotensive group. We trained 3 ML models, specifically logistic regression, k-nearest-neighbors, and random forest (RF), to predict the existence of hypertension in patients based only on a few basic clinical parameters and ECG-derived features. We also calculated Shapley additive explanations (SHAP), a sophisticated feature importance analysis, to interpret each feature's role in the random forest's predictions.

Results

Our RF model was able to distinguish hypertensive from normotensive patients with accuracy 84.2%, specificity 66.7%, sensitivity 91.4%, and area under the receiver-operating curve 0.86. Age, BMI, BMI-adjusted Cornell criteria (BMI multiplied by RaVL+SV3), R wave amplitude in aVL, and BMI-modified Sokolow-Lyon voltage (BMI divided by SV1+RV5), were the most important anthropometric and ECG-derived features in terms of the success of our model. Figure 1 shows the results in detecting hypertension by the Random Forest.

Conclusions

Our ML algorithm is effective in the detection of hypertension in patients using ECG-derived and basic anthropometric criteria. Our findings open new horizon in the detection of many undiagnosed hypertensive individuals who have an increased cardiovascular disease risk.

Funding Acknowledgement

Type of funding sources: None.

Usefulness of right ventricular longitudinal systolic strain to predict the progression to heart failure with preserved ejection fraction in hypertensive patients

Background

Accurate assessment of right ventricular (RV) systolic function is important, as it is an established prognostic marker in cardiac diseases. Speckle-tracking echocardiography is a sensitive tool for detection of subclinical left ventricular impairment in essential hypertension.

Purpose

Our aim was to investigate the usefulness of RV longitudinal peak systolic strain (LS) to predict the risk of future development of heart failure with preserved ejection fraction (HFpEF) in patients with essential hypertension

Methods

We performed a retrospective observational study that included 453 patients with essential hypertension (266 males, aged 63±18 years) and 175 normotensives (100 males, aged 66±15 years). Standard echocardiography was performed at the initial visit. 2D speckle tracking echocardiography with evaluation of longitudinal strain in each segment of the RV (basal: RVLS-B; mid: RVLS-M, apical: RVLS-A) and global RV free-wall strain (RVLS-G) were also performed. We studied the cases of new onset HFpEF in hypertensive patients.

Results

The median follow up was 85 months (22–122). RVLS-G, RVLS-B and RVLS-M were significantly impaired in hypertensives compared to controls (RVLS-G: −16.1±9.7 vs −20.0±5.1, RVLS-B: −11.7±3.7 vs −20.6±3.3, RVLS-M:-16.3±5.4 vs −20.7±4.9, p<0.05 for all). No significant difference was detected for the RVLS-A (−20.1±3.8 for hypertensives vs −21.31±6.5 for controls, p=NS). Thirty two hypertensive patients developed HFpEF (7%). A cut-off RVLS-G worse than −17% was significantly associated with new onset HFpEF (p<0.001) in those patients. A multivariate Cox regression analysis showed that RVLS-G had independent significant prognostic value for the risk of HFpEF (HR: 10.5, 95% confidence interval (CI): 7.3–25.4).

Conclusions

Essential hypertension leads to a decrease of RVLS which is strong predictor of a new onset HFpEF. Future studies are needed to assess the significance of these findings and the effect of treatment.

Funding Acknowledgement

Type of funding sources: None.

Right ventricular longitudinal systolic strain can predict new onset heart failure with preserved ejection fraction in hypertensive patients

Funding Acknowledgements

Type of funding sources: None.

Purpose

Accurate assessment of right ventricular (RV) systolic function is important, as it is an established prognostic marker in cardiac diseases. Speckle-tracking echocardiography is a sensitive tool for detection of subclinical left ventricular impairment in essential hypertension. We associated RV function using longitudinal peak systolic strain (GLS) in patients with essential hypertension with the risk of future development of heart failure with preserved ejection fraction (HFpEF).

Methods

 We performed a retrospective observational study that included 458 patients with essential hypertension (266 males, aged 63 ± 18 years) and 179 normotensives (100 males, aged 66 ± 15 years). Standard echocardiography was performed at the initial visit. 2D speckle tracking echocardiography with evaluation of longitudinal strain in each segment of the RV (basal:  RVLS-B; mid: RVLS-M, apical: RVLS-A) and global RV free-wall strain (RVLS-G) were also performed. We studied the cases of new onset HFpEF in hypertensive patients. 

Results

The median follow up was 85 months (22–122). RVLS-G, RVLS-B and RVLS-M were significantly impaired in hypertensives compared to controls (RVLS-G: -16.1 ± 9.7 vs -20.0 ± 5.1, RVLS-B: -11.7 ± 3.7 vs -20.6 ± 3.3, RVLS-M:-16.3 ± 5.4 vs -20.7 ± 4.9, p < 0.05 for all). No significant difference was detected for the RVLS-A (-20.1 ± 3.8 for hypertensives vs -21.31 ± 6.5 for controls, p = NS). Thirty two hypertensive patients developed HFpEF (7 %). A cut-off RVLS-G worse than -17 % was significantly associated with new onset HFpEF (p< 0.001) in those patients. A multivariate Cox regression analysis showed that RVLS-G had independent significant prognostic value for the risk of HFpEF (HR: 10.5, 95% confidence interval (CI): 7.3-25.4). 

Conclusions

Essential hypertension leads to a decrease of RVLS which is strong predictor of a new onset HFpEF. Future studies are needed to assess the significance of these findings and the effects of treatment.

Standardized practices for RNA diagnostics using clinically accessible specimens reclassifies 75% of putative splicing variants

PURPOSE

Genetic variants causing aberrant premessenger RNA splicing are increasingly being recognized as causal variants in genetic disorders. In this study, we devise standardized practices for polymerase chain reaction (PCR)-based RNA diagnostics using clinically accessible specimens (blood, fibroblasts, urothelia, biopsy).

METHODS

A total of 74 families with diverse monogenic conditions (31% prenatal-congenital onset, 47% early childhood, and 22% teenage-adult onset) were triaged into PCR-based RNA testing, with comparative RNA sequencing for 19 cases.

RESULTS

Informative RNA assay data were obtained for 96% of cases, enabling variant reclassification for 75% variants that can be used for genetic counseling (71%), to inform clinical care (32%) and prenatal counseling (41%). Variant-associated mis-splicing was highly reproducible for 28 cases with samples from ≥2 affected individuals or heterozygotes and 10 cases with ≥2 biospecimens. PCR amplicons encompassing another segregated heterozygous variant was vital for clinical interpretation of 22 of 79 variants to phase RNA splicing events and discern complete from partial mis-splicing.

CONCLUSION

RNA diagnostics enabled provision of a genetic diagnosis for 64% of recruited cases. PCR-based RNA diagnostics has capacity to analyze 81.3% of clinically significant genes, with long amplicons providing an advantage over RNA sequencing to phase RNA splicing events. The Australasian Consortium for RNA Diagnostics (SpliceACORD) provide clinically-endorsed, standardized protocols and recommendations for interpreting RNA assay data.

Scaling national and international improvement in virtual gene panel curation via a collaborative approach to discordance resolution

Clinical validity assessments of gene-disease associations underpin analysis and reporting in diagnostic genomics, and yet wide variability exists in practice, particularly in use of these assessments for virtual gene panel design and maintenance. Harmonization efforts are hampered by the lack of agreed terminology, agreed gene curation standards, and platforms that can be used to identify and resolve discrepancies at scale. We undertook a systematic comparison of the content of 80 virtual gene panels used in two healthcare systems by multiple diagnostic providers in the United Kingdom and Australia. The process was enabled by a shared curation platform, PanelApp, and resulted in the identification and review of 2,144 discordant gene ratings, demonstrating the utility of sharing structured gene-disease validity assessments and collaborative discordance resolution in establishing national and international consensus.

NCKAP1 Disruptive Variants Lead to a Neurodevelopmental Disorder with Core Features of Autism

NCKAP1/NAP1 regulates neuronal cytoskeletal dynamics and is essential for neuronal differentiation in the developing brain. Deleterious variants in NCKAP1 have been identified in individuals with autism spectrum disorder (ASD) and intellectual disability; however, its clinical significance remains unclear. To determine its significance, we assemble genotype and phenotype data for 21 affected individuals from 20 unrelated families with predicted deleterious variants in NCKAP1. This includes 16 individuals with de novo (n = 8), transmitted (n = 6), or inheritance unknown (n = 2) truncating variants, two individuals with structural variants, and three with potentially disruptive de novo missense variants. We report a de novo and ultra-rare deleterious variant burden of NCKAP1 in individuals with neurodevelopmental disorders which needs further replication. ASD or autistic features, language and motor delay, and variable expression of intellectual or learning disability are common clinical features. Among inherited cases, there is evidence of deleterious variants segregating with neuropsychiatric disorders. Based on available human brain transcriptomic data, we show that NCKAP1 is broadly and highly expressed in both prenatal and postnatal periods and demostrate enriched expression in excitatory neurons and radial glias but depleted expression in inhibitory neurons. Mouse in utero electroporation experiments reveal that Nckap1 loss of function promotes neuronal migration during early cortical development. Combined, these data support a role for disruptive NCKAP1 variants in neurodevelopmental delay/autism, possibly by interfering with neuronal migration early in cortical development.

Detection of Right-to-Left Cardiac Shunt in the Absence of Transcranial Acoustic Bone

PURPOSE

Paradoxical thrombotic embolism via right-to-left cardiac shunt (RLS) is a risk factor of cryptogenic ischemic stroke. Transtemporal Doppler (TTD) is a valid method used in the detection of patent foramen ovale (PFO). Temporal acoustic bone windows are missing with increasing age and in some younger subjects. We studied prospectively whether Doppler ultrasound of the cervical arteries (submandibular internal carotid artery [ICA] and vertebral artery [VA]) is an alternative, when compared to TTD, in the detection and quantification of PFO.

MATERIAL AND METHODS

A total of 94 patients with sufficient temporal bone windows suffering from recent ischemic stroke underwent TTD and ICA (n = 51) or TTD and VA (n = 43). After injection of microbubbles, the numbers of artificial high-intensity signals (HITS) were recorded at rest and after Valsalva maneuver.

RESULTS

For 47 patients in the ICA group, an RLS was found at rest in 23 patients and after Valsalva in 28 patients. At rest, sensitivity was 100%, specificity 96%, positive predictive value (ppv) 95.6%, and negative predictive value (npv) 100%. After Valsalva, sensitivity was 100%, specificity 95%, ppv 96.4%, npv 100%. For 43 patients in the VA group an RLS was found at rest in 14 patients and after Valsalva in 19 patients. At rest, sensitivity was 71.4%, specificity 100%, ppv 100%, and npv 87.8%. After Valsalva, 94.4%, 96%, 94.4%, and 96%, respectively. Pearson's correlations of the number of HITS between TTD and ICA and between TTD and VA were highly significant.

CONCLUSIONS

When transcranial acoustic bone windows are missing, Doppler ultrasound of the cervical submandibular ICA and VAs are valid screening methods to detect RLS due to a PFO.

Retronasal olfactory function in Parkinson's disease

OBJECTIVES/HYPOTHESIS

Orthonasal olfaction is severely altered in PD patients. Retronasal olfactory function has been shown to be preserved under certain conditions even in the absence of orthonasal function. This study was undertaken to investigate retronasal versus orthonasal olfactory function in Parkinson's disease (PD).

STUDY DESIGN

Prospective study.

METHODS

A total of 45 PD patients (mean age, 61 years; range 26-82 years) underwent orthonasal olfactory testing with a standardized olfactory test (Sniffin' Sticks) and retronasal olfactory testing with a 10-item identification kit based on aromatized powders.

RESULTS

Regarding orthonasal tests, all PD patients scored within the range of hyposmia and functional anosmia. The mean correct orthonasal identification score for PD patients was 56% +/- 2.6%, and the mean retronasal identification rate was 60% +/- 3%. There was no significant difference between ortho- and retronasal odor identification (P = .15).

CONCLUSIONS

The present study shows that retronasal and orthonasal olfactory function are severely impaired in PD patients, and this impairment is of similar magnitude for both functions. The contribution of this finding to the food-intake behavior of PD patients is discussed.

Restless legs syndrome: an early manifestation of Huntington's disease?

BACKGROUND

Far from being uniform, Huntington's disease (HD)'s phenotype encompasses a large variety of motor and non-motor symptoms which occur in various combinations in individual patients.

AIM

To describe an unusual association between restless legs syndrome (RLS) and HD.

METHODS AND RESULTS

We report a patient with an atypical presentation of genetically demonstrated HD, who developed typical RLS a few years prior to and during the course of HD. Common causes of RLS were excluded and the polysomnography confirmed frequent and severe periodic limb movements during sleep and while awake.

CONCLUSIONS

We propose RLS as an uncommon but early feature of HD in some patients, and suggest adding HD to the already long list of RLS secondary to neurodegenerative conditions.