Plekhm2 acts as an autophagy modulator in murine heart and cardiofibroblasts.

Plekhm2 is a protein regulating endosomal trafficking and lysosomal distribution. We recently linked a recessive inherited mutation in PLEKHM2 to a familial form of dilated cardiomyopathy and left ventricular non-compaction. These patients' primary fibroblasts exhibited abnormal lysosomal distribution and autophagy impairment. We therefore hypothesized that loss of PLEKHM2 impairs cardiac function via autophagy derangement. Here, we characterized the roles of Plekhm2 in the heart using global Plekhm2 knockout (PLK2-KO) mice and cultured cardiac cells. Compared to littermate controls (WT), young PLK2-KO mice exhibited no difference in heart function or autophagy markers but demonstrated higher basal AKT phosphorylation. Older PLK2-KO mice had body and heart growth retardation and increased LC3II protein levels. PLK2-KO mice were more vulnerable to fasting and, interestingly, impaired autophagy was noted in vitro, in Plekhm2-deficient cardiofibroblasts but not in cardiomyocytes. PLK2-KO hearts appeared to be less sensitive to pathological hypertrophy induced by angiotensin-II compared to WT. Our findings suggest a role of Plekhm2 in murine cardiac autophagy. Plekhm2 deficiency impaired autophagy in cardiofibroblasts, but the autophagy in cardiomyocytes is not critically dependent on Plekhm2. The absence of Plekhm2 in mice appears to promote compensatory mechanism(s) enabling the heart to manage angiotensin-II-induced stress without detrimental consequences.

Myocarditis-A Helpful Algorithm to Overcome Diagnostic Challenges in the Pediatric Population.

OBJECTIVES: This study was designed to investigate clinical differences between pediatric patients who presented with chest pain, tachycardia, and/or tachypnea who subsequently were or were not diagnosed with myocarditis. The results were used to develop a decision tree to aid in rapid diagnosis of pediatric myocarditis. METHODS: A retrospective case-control study was performed using the electronic medical records of children aged 0 to 18 years between the years 2003 and 2020 with a complaint of chest pain, tachycardia, and/or tachypnea. Patients included in the study were those diagnosed with myocarditis and those with suspected myocarditis, which was ultimately ruled out. Demographic and clinical differences between the research groups were analyzed. A decision tree was rendered using the rpart (Recursive Partitioning and Regression Trees) package. RESULTS: Four thousand one hundred twenty-five patients were screened for eligibility. Seventy-three myocarditis patients and 292 nonmyocarditis patients were included. Compared with the control group, the study group was found to have a higher mean respiratory rate (37 ± 23 vs 23 ± 7 breaths per minute) and mean heart rate (121 ± 44 vs 97 ± 25 beats per minute) and lower mean systolic and diastolic blood pressure (102 ± 27/56 ± 17 mm Hg vs 114 ± 14/67 ± 10 mm Hg). The mean white blood cell count was greater in the case group (13 ± 6 vs 10 ± 5 × 103/µL). A decision tree was rendered using simple demographic and clinical variables. The accuracy of the algorithm was 85.2%, with 100% accuracy in patients aged 0 to 2.5 years and 69% in patients aged 2.5 to 18 years. CONCLUSION: The clinical and laboratory characteristics described in this study were similar to what is described in the literature. The decision tree may aid in the diagnosis of myocarditis in patients 2.5 years and younger. In the population aged 2.5 to 18 years, the decision tree did not constitute an adequate tool for detecting myocarditis.

Compound Heterozygosity for Late-Onset Cardiomyopathy-Causative ALPK3 Coding Variant and Novel Intronic Variant Cause Infantile Hypertrophic Cardiomyopathy.

Hypertrophic and dilated cardiomyopathy (HCM, DCM) are leading causes of cardiovascular morbidity and mortality in children. The pseudokinase alpha-protein kinase 3 (ALPK3) plays an essential role in sarcomere organization and cardiomyocyte differentiation. ALPK3 coding mutations are causative of recessively inherited pediatric-onset DCM and HCM with variable expression of facial dysmorphism and skeletal abnormalities and implicated in dominantly inherited adult-onset cardiomyopathy. We now report two variants in ALPK3-a coding variant and a novel intronic variant affecting splicing. We demonstrate that compound heterozygosity for both variants is highly suggestive to be causative of infantile-onset HCM with webbed neck, and heterozygosity for the coding variant presents with adult-onset HCM. Our data validate partial penetrance of heterozygous loss-of-function ALPK3 mutations in late-onset hypertrophic cardiomyopathy and expand the genotypic spectrum of autosomal recessive ALPK3-related cardiac disease with Noonan-like features.

Functional defects in hiPSCs-derived cardiomyocytes from patients with a PLEKHM2-mutation associated with dilated cardiomyopathy and left ventricular non-compaction.

Dilated cardiomyopathy (DCM) is a primary myocardial disease, leading to heart failure and excessive risk of sudden cardiac death with rather poorly understood pathophysiology. In 2015, Parvari's group identified a recessive mutation in the autophagy regulator, PLEKHM2 gene, in a family with severe recessive DCM and left ventricular non-compaction (LVNC). Fibroblasts isolated from these patients exhibited abnormal subcellular distribution of endosomes, Golgi apparatus, lysosomes and had impaired autophagy flux. To better understand the effect of mutated PLEKHM2 on cardiac tissue, we generated and characterized induced pluripotent stem cells-derived cardiomyocytes (iPSC-CMs) from two patients and a healthy control from the same family. The patient iPSC-CMs showed low expression levels of genes encoding for contractile functional proteins (α and ß-myosin heavy chains and 2v and 2a-myosin light chains), structural proteins integral to heart contraction (Troponin C, T and I) and proteins participating in Ca2+ pumping action (SERCA2 and Calsequestrin 2) compared to their levels in control iPSC-derived CMs. Furthermore, the sarcomeres of the patient iPSC-CMs were less oriented and aligned compared to control cells and generated slowly beating foci with lower intracellular calcium amplitude and abnormal calcium transient kinetics, measured by IonOptix system and MuscleMotion software. Autophagy in patient's iPSC-CMs was impaired as determined from a decrease in the accumulation of autophagosomes in response to chloroquine and rapamycin treatment, compared to control iPSC-CMs. Impairment in autophagy together with the deficiency in the expression of NKX2.5, MHC, MLC, Troponins and CASQ2 genes, which are related to contraction-relaxation coupling and intracellular Ca2+ signaling, may contribute to the defective function of the patient CMs and possibly affect cell maturation and cardiac failure with time.

A Novel Mutation in the ADAMTS10 Associated with Weil-Marchesani Syndrome with a Unique Presentation of Developed Membranes Causing Severe Stenosis of the Supra Pulmonic, Supramitral, and Subaortic Areas in the Heart.

Weill-Marchesani syndrome (WMS) is a rare genetic inherited disorder with autosomal recessive and dominant modes of inheritance. WMS is characterized by the association of short stature, brachydactyly, joint stiffness, eye anomalies, including microspherophakia and ectopia of the lenses, and, occasionally, heart defects. We investigated the genetic cause of a unique and novel presentation of heart-developed membranes in the supra-pulmonic, supramitral, and subaortic areas, creating stenosis that recurred after their surgical resection in four patients from one extended consanguineous family. The patients also presented ocular findings consistent with Weill-Marchesani syndrome (WMS). We used whole exome sequencing (WES) to identify the causative mutation and report it as a homozygous nucleotide change c. 232T>C causing p. Tyr78His in ADAMTS10. ADAMTS10 (ADAM Metallopeptidase with Thrombospondin Type 1 Motif 10) is a member of a family of zinc-dependent extracellular matrix protease family. This is the first report of a mutation in the pro-domain of ADAMTS10. The novel variation replaces a highly evolutionary conserved tyrosine with histidine. This change may affect the secretion or function of ADAMTS10 in the extracellular matrix. The compromise in protease activity may thus cause the unique presentation of the developed membranes in the heart and their recurrence after surgery.

A Missense Variation in PHACTR2 Associates with Impaired Actin Dynamics, Dilated Cardiomyopathy, and Left Ventricular Non-Compaction in Humans.

Dilated cardiomyopathy (DCM) with left ventricular non-compaction (LVNC) is a primary myocardial disease leading to contractile dysfunction, progressive heart failure, and excessive risk of sudden cardiac death. Using whole-exome sequencing to investigate a possible genetic cause of DCM with LVNC in a consanguineous child, a homozygous nucleotide change c.1532G>A causing p.Arg511His in PHACTR2 was found. The missense change can affect the binding of PHACTR2 to actin by eliminating the hydrogen bonds between them. The amino acid change does not change PHACTR2 localization to the cytoplasm. The patient's fibroblasts showed a decreased globular to fibrillary actin ratio compared to the control fibroblasts. The re-polymerization of fibrillary actin after treatment with cytochalasin D, which disrupts the actin filaments, was slower in the patient's fibroblasts. Finally, the patient's fibroblasts bridged a scar gap slower than the control fibroblasts because of slower and indirect movement. This is the first report of a human variation in this PHACTR family member. The knock-out mouse model presented no significant phenotype. Our data underscore the importance of PHACTR2 in regulating the monomeric actin pool, the kinetics of actin polymerization, and cell movement, emphasizing the importance of actin regulation for the normal function of the human heart.

Duchenne Muscular Dystrophy and Early Onset Hypertrophic Cardiomyopathy associated with Mutations in Dystrophin and Hypertrophic Cardiomyopathy-Associated Genes.

Duchenne muscular dystrophy (DMD) is a progressive muscular damage disorder caused by mutations in dystrophin gene. Cardiomyopathy may first be evident after 10 years of age and increases in incidence with age. We present a boy diagnosed at 18 months with a rare phenotype of DMD in association with early-onset hypertrophic cardiomyopathy (HCM). The cause of DMD is a deletion of exons 51-54 of dystrophin gene. The cause of HCM was verified by whole exome sequencing. Novel missense variations in two genes: MAP2K5 inherited from the mother and ACTN2 inherited from the father, or de novo. The combination of MAP2K5 , ACTN2 , and dystrophin mutations, could be causing the HCM in our patient. This is the second patient diagnosed, at relatively young age, with DMD and HCM, with novel variations in genes known to cause HCM. This study demonstrates the need for genetic diagnosis to elucidate the underlying pathology of HCM.

Dock10 Regulates Cardiac Function under Neurohormonal Stress.

Dedicator of cytokinesis 10 (Dock10) is a guanine nucleotide exchange factor for Cdc42 and Rac1 that regulates the JNK (c-Jun N-terminal kinase) and p38 MAPK (mitogen-activated protein kinase) signaling cascades. In this study, we characterized the roles of Dock10 in the myocardium. In vitro: we ablated Dock10 in neonatal mouse floxed Dock10 cardiomyocytes (NMCMs) and cardiofibroblasts (NMCFs) by transduction with an adenovirus expressing Cre-recombinase. In vivo, we studied mice in which the Dock10 gene was constitutively and globally deleted (Dock10 KO) and mice with cardiac myocyte-specific Dock10 KO (Dock10 CKO) at baseline and in response to two weeks of Angiotensin II (Ang II) infusion. In vitro, Dock10 ablation differentially inhibited the α-adrenergic stimulation of p38 and JNK in NMCM and NMCF, respectively. In vivo, the stimulation of both signaling pathways was markedly attenuated in the heart. The Dock10 KO mice had normal body weight and cardiac size. However, echocardiography revealed mildly reduced systolic function, and IonOptix recordings demonstrated reduced contractility and elevated diastolic calcium levels in isolated cardiomyocytes. Remarkably, Dock10 KO, but not Dock10 CKO, exaggerated the pathological response to Ang II infusion. These data suggest that Dock10 regulates cardiac stress-related signaling. Although Dock10 can regulate MAPK signaling in both cardiomyocytes and cardiofibroblasts, the inhibition of pathological cardiac remodeling is not apparently due to the Dock10 signaling in the cardiomyocyte.

Clinical Application of Postmortem Magnetic Resonance Imaging in Neonates.

BACKGROUND: Recent reports advocate the use of MRI either as a substitute for postmortem examinations or for a more targeted autopsy. METHODS: A full-body postmortem MRI (pMRI) of infants was performed as early as possible after death, and findings were compared to clinical premortem diagnoses. RESULTS: Thirty-one infants were scanned during the study period. Median gestation at birth was 34 weeks (ranges: 24-43). In 3 (10%) cases, no new findings were detected. In 2 (6%), new minor findings not related to the cause of death were detected, and in 17 (55%), new minor findings related to the cause of death were detected. New major findings related to the cause of death were detected in 4 (13%) cases, and new major findings not related to the cause of death were detected in 5 (16%) cases. In 3 (10%), findings thought to alter the perceived cause of death were detected. Overall, in 23 (74%) cases, pMRI findings reinforced the clinical premortem diagnoses. CONCLUSIONS: pMRI is a culturally accepted alternative when autopsy is not performed and can either reinforce, refute, or add to premortem clinical diagnoses.

Hepatic and cardiac iron load as determined by MRI T2* in patients with congenital dyserythropoietic anemia type I.

Iron overload comprises one of the main complications of congenital dyserythropoietic anemia type I (CDA-I). When analyzing magnetic resonance imaging T2* (MRI T2*) results in CDA patients, two previous studies reported discordant results regarding iron load in these patients. To further understand iron loading pattern in this group of patients, we analyzed MRI T2* findings in 46 CDA-I patients. Mild to moderate hepatic iron overload was detected in 28/46 (60.8%) patients. A significant correlation was found between serum ferritin and liver iron concentration (LIC). A significant correlation (p value = 0.02) was also found between the patient's age and LIC, reflecting increased iron loading over time, even in the absence of transfusion therapy. Notably, no cardiac iron overload was detected in any patient. Transfusion-naive patients had better LIC and better cardiac T2* values. These results demonstrate that a high percentage of CDA-I patients have liver iron concentration above the normal values, risking them with significant morbidity and mortality, and emphasize the importance of periodic MRI T2* studies for direct assessment of tissue iron concentration in these patients, taking age and transfusional burden into consideration.

A Novel Recessive Mutation in SPEG Causes Early Onset Dilated Cardiomyopathy.

Dilated cardiomyopathy (DCM) is a common cause of heart failure and sudden cardiac death. It has been estimated that up to half of DCM cases are hereditary. Mutations in more than 50 genes, primarily autosomal dominant, have been reported. Although rare, recessive mutations are thought to contribute considerably to DCM, especially in young children. Here we identified a novel recessive mutation in the striated muscle enriched protein kinase (SPEG, p. E1680K) gene in a family with nonsyndromic, early onset DCM. To ascertain the pathogenicity of this mutation, we generated SPEG E1680K homozygous mutant human induced pluripotent stem cell derived cardiomyocytes (iPSC-CMs) using CRISPR/Cas9-mediated genome editing. Functional studies in mutant iPSC-CMs showed aberrant calcium homeostasis, impaired contractility, and sarcomeric disorganization, recapitulating the hallmarks of DCM. By combining genetic analysis with human iPSCs, genome editing, and functional assays, we identified SPEG E1680K as a novel mutation associated with early onset DCM and provide evidence for its pathogenicity in vitro. Our study provides a conceptual paradigm for establishing genotype-phenotype associations in DCM with autosomal recessive inheritance.

Prevalence of left ventricular hypertrabeculation/noncompaction among patients with congenital dyserythropoietic anemia Type 1 (CDA1).

BACKGROUND: Congenital dyserythropoietic anemia type 1 (CDA1) is a rare autosomal recessive disease characterized by macrocytic anemia, ineffective erythropoiesis, and secondary hemochromatosis. Left-ventricular noncompaction (LVNC) is a cardiomyopathy that is commonly attributed to intrauterine arrest of normal compaction during the endomyocardial morphogenesis. LV hypertrabeculation/noncompaction (LVHT/NC) morphology, however, might exist in various hemoglobinopathies. Our primary objective was to determine whether the pattern of LVHT/NC is more prevalent among patients with CDA1, in comparison to subjects without CDA1, and to find potential risk factors for LVHT/NC among these patients. Our secondary objective was to evaluate the clinical implication of LVHT/NC. METHODS: We retrospectively assessed 32 CDA1 patients (median age 17.5, range 6-61) that underwent routine assessment of iron overload by cardiac magnetic resonance. Number and distribution of noncompacted LV segments were assessed in CDA1 patients and compared to 64 age- and gender-matched patients without CDA1. The ratio of noncompacted to compacted myocardium (NC/C ratio) in end-diastole was calculated for each of the three long-axis views. NC/C ratio > 2.3 was considered diagnostic for LVHT/NC. RESULTS: In multivariate analysis, the presence of CDA1 was independently associated with NC/C ratio > 2.3, a feature of LVHT/NC (adjusted OR = 11.46, 95%CI = 2.6-50.68, p = .001). CDA1 was strongly associated with increased number of myocardial segments exhibiting LVHT/NC pattern. Cardiac volumes and ejection fraction were preserved without clinical adverse events in long term follow-up. CONCLUSIONS: CDA1 patients have a higher prevalence of LVHT/NC than normal individuals, independent of myocardial iron overload and without effect on ejection fraction or clinical outcome.

Gastric Drainage in the Treatment of Near-Fatal Food-Induced Anaphylaxis.

Anaphylaxis should be treated with early administration of intramuscular Adrenalin; however, fatalities may still occur even with this therapy. We report a patient with near-fatal anaphylaxis due to milk whose symptoms persisted and were resistant to any therapeutic attempt; however, the patient had a prompt resolution of the anaphylaxis shortly after a nasogastric tube placement with gastric drainage, suggesting that this procedure ended the ongoing absorption of additional allergen from the gastrointestinal tract. We suggest that nasogastric drainage of gastric contents should be considered as part of the therapy in severe food-induced anaphylaxis.

Risk factors for congenital heart defects in two populations residing in the same geographic area: a long-term population-based study, Southern Israel.

BACKGROUND: Congenital Heart Defects (CHD) are the most common structural defects of newborns. Southern Israel's population is comprised of Jews (75%) and Arab-Bedouins (25%). The latter has a high rate of consanguinity and low abortion rate compared with the Jewish population, which led us to suspect a higher CHD prevalence in this population. Our aim was to compare maternal risk factors that are associated with CHD in these populations. METHODS: All births during 1991-2011 in Soroka University Medical Center (n = 247, 289) with 6078 newborns having CHD were included. To account for same-woman deliveries, general estimating equation models adjusted for ethnicity, gender and birth number were used. RESULTS: The total prevalence of CHD was 24.6/1000 live births, with 21.4 and 30 among Jewish and Bedouin populations, respectively, (p = 0.001). Multi-variant analysis of risk factors for CHD revealed that risk factors common to both populations included conception with fertility medications, sibling CHD, maternal CHD, diabetes mellitus, hypertension and anaemia. Risk factors that were specific for the Bedouin population were - maternal age over 35 years, recurrent pregnancy loss and in vitro fertilisation. However, sibling CHD was more common as a CHD risk factor in the Jewish compared with the Bedouin population (Adjusted OR 10.23 versus 3.19, respectively). CONCLUSIONS: The prevalence of CHD is higher in both the Bedouin and Jewish populations than previously reported. Several maternal factors were associated with CHD specifically for a certain population. Risk factors for CHD vary in populations residing in the same geographic area.

CAP2 mutation leads to impaired actin dynamics and associates with supraventricular tachycardia and dilated cardiomyopathy.

BACKGROUND: Dilated cardiomyopathy (DCM) is a primary myocardial disease leading to contractile dysfunction, progressive heart failure and excessive risk of sudden cardiac death. Around half of DCM cases are idiopathic, and genetic factors seem to play an important role. AIM: We investigated a possible genetic cause of DCM in two consanguineous children from a Bedouin family. METHODS AND RESULTS: Using exome sequencing and searching for rare homozygous variations, we identified a nucleotide change in the donor splice consensus sequence of exon 7 in CAP2 as the causative mutation. Using patient-derived fibroblasts, we demonstrated that the mutation causes skipping of exons 6 and 7. The resulting protein is missing 64 amino acids in its N-CAP domain that should prevent its correct folding. CAP2 protein level was markedly reduced without notable compensation by the homolog CAP1. However, ß-actin mRNA was elevated as demonstrated by real-time qPCR. In agreement with the essential role of CAP2 in actin filament polymerization, we demonstrate that the mutation affects the kinetics of repolymerization of actin in patient fibroblasts. CONCLUSIONS: This is the first report of a recessive deleterious mutation in CAP2 and its association with DCM in humans. The clinical phenotype recapitulates the damaging effects on the heart observed in Cap2 knockout mice including DCM and cardiac conduction disease, but not the other effects on growth, viability, wound healing and eye development. Our data underscore the importance of the proper kinetics of actin polymerization for normal function of the human heart.

Streptobacillus moniliformis Endocarditis: An Unusual Case of Pulmonary Valve Erosion Resulting in Free Pulmonary Regurgitation and Aneurysm.

Endocarditis is a consideration in the differential diagnosis when masses are seen on echocardiography in a patient with congenital heart disease. We present a case of insidious development of endocarditis caused by Streptobacillus moniliformis in a seven-month-old baby after a rat bite, when the baby was three months of age.

Elevated birth prevalence of conotruncal heart defects in a population with high consanguinity rate.

BACKGROUND: The aetiology of conotruncal heart defects is poorly understood and the birth prevalence varies geographically. The known risk factors for developing conotruncal heart defects are as follows: CHD in siblings, genetic chromosomal abnormalities, paternal age >30 years, high parity, low birth weight, prematurity, and maternal diabetes. OBJECTIVE: The aim of this study was to characterise conotruncal heart defects, birth prevalence, mortality, and morbidity in the population of southern Israel, of whom 75% are Jewish and the rest are mostly Bedouin Arabs. METHODS: The data were obtained from Soroka University Medical Center database of births and newborns. Conotruncal heart defects cases were identified by ICD9 codes. RESULTS: During 1991-2011, there were 247,290 singleton live births and 393 conotruncal heart defects in Soroka University Medical Center. The birth prevalence per 10,000 live births of tetralogy of Fallot, transposition of the great arteries, and truncus arteriosus was 9.5, 5, and 1.8, respectively. In the multivariate analysis, Bedouin descent (adjusted odds ratio 2.40, p35 years (1.66, p=0.004), and siblings with congenital heart defects (1.98, p=0.005) were associated with tetralogy of Fallot, and Bedouin descent (1.61, p=0.05), siblings with congenital heart defects (2.19, p=0.004), and diabetes mellitus (7.15, p<0.001) were associated with transposition of the great arteries. In a univariate analysis, Bedouin descent (p=0.004) and congenital heart defects in siblings (p<0.001) were associated with truncus arteriosus. CONCLUSION: We observed higher birth prevalence of conotruncal heart defects compared with the birth prevalence reported worldwide, specifically among the Bedouins, a population characterised with high consanguinity rate. Therefore, genetic counselling and early fetal echocardiograms should be encouraged, especially in high consanguinity rate populations. Naturally, further educational efforts are needed in order to decrease consanguinity and its related consequences.

Morbidity and mortality of adult patients with congenital dyserythropoietic anemia type I.

Congenital dyserythropoietic anemia type I (CDAI) is a rare autosomal recessive disease characterized by macrocytic anemia, ineffective erythropoiesis, and secondary hemochromatosis. To better define the natural history of the disease among adult patients, we studied 32 Bedouin patients (median age 34 yr; range 21-60) all carrying the same CDAN1 founder mutation. Follow-up studies included complete blood count, blood chemistry, abdominal ultrasound, echocardiography, and T2*MRI. Main complications were due to anemia and ineffective erythropoiesis [osteoporosis (8/9, 89%), cholelithiasis (21/30, 70%), pulmonary arterial hypertension (PAH) (6/25, 24%)] and iron overload [hypothyroidism (9/24, 38%), and diabetes mellitus (6/32, 19%)]. T2* MRI revealed increased liver iron but no cardiac iron (13/13). Anemia improved in the majority of patients who underwent splenectomy (5/6). Three patients died (9%) at the age of 46-56 due to PAH (1) and sepsis (2). All previously underwent splenectomy. Analyzing both our patients and the 21 patients previously described by Heimpel et al. (Blood 107:334, 2006), we conclude that adults with CDA I suffer significant morbidity and mortality. Careful monitoring of iron overload and prompt iron chelation therapy is mandatory. Due to possible complications and inconsistent response to splenectomy α-interferon, transfusion therapy or stem cell transplantation should be considered as alternatives to this procedure in severely affected patients.

D117N in Cypher/ZASP may not be a causative mutation for dilated cardiomyopathy and ventricular arrhythmias.

Dilated cardiomyopathy (DCM) and malignant ventricular arrhythmias are important causes of congestive heart failure, heart transplantation, and sudden cardiac death in young patients. Cypher/ZASP is a cytoskeletal protein localized in the sarcomeric Z-line that has a pivotal role in maintaining adult cardiac structure and function. The putative mutation p.(D117N) in Cypher/ZASP has been suggested to cause systolic dysfunction, dilated left ventricle with hypertrabeculated myocardium, and intraventricular conduction disturbance, based on two reported sporadic cases. In two unrelated Bedouin families, one with pediatric DCM and the other with DCM and ventricular arrhythmias at young adulthood searching for the causative mutation by exome sequencing we identified the p.(D117N) variant in Cypher/ZASP. However, p.(D117N) did not segregate as the causative mutation in these families, i.e. it was not present in some patients and was found in several individuals who had no clinical manifestations. Furthermore, the carrier frequency in the Bedouin population of origin is estimated to be 5.2%, which is much higher than the incidence of idiopathic DCM in this population. Thus, our data support the notion that the p.(D117N) variant in Cypher/ZASP is not a causative mutation in the families tested by us. The results also indicates that at least in some cases, the p.(D117N) in Cypher/ZASP is not a causative mutation and the role of D117N in Cypher/ZASP in cardiac pathologies should be further clarified and re-evaluated.