Intermediate-effect size p.Arg637Gln in FHOD3 increases risk of HCM and is associated with an aggressive phenotype in homozygous carriers

Formin homology 2 domain-containing 3 (FHOD3) gene has emerged as one of the main non-sarcomeric genes associated with hypertrophic cardiomyopathy (HCM), but no cases of biallelic variants associated with disease have been described to date. From 2014 until 2021, FHOD3 was evaluated in our center by next-generation sequencing in 22 806 consecutive unrelated probands. The p.Arg637Gln variant in FHOD3 was enriched in our HCM cohort (284 of 9668 probands; 2.94%) compared with internal controls (64 of 11 480; 0.59%) and gnomAD controls (373 of 64 409; 0.58%), with ORs of 5.40 (95% CI: 4.11 to 7.09) and 5.19 (95% CI: 4.44 to 6.07). The variant affects a highly conserved residue localised in a supercoiled alpha helix considered a clustering site for HCM variants, and in heterozygosis can act as a predisposing factor (intermediate-effect variant) for HCM, with an estimated penetrance of around 1%. Additionally, seven homozygous carriers of p.Arg637Gln in FHOD3 were identified. All but one (unaffected) showed an early presentation and a severe HCM phenotype. All this information suggest that p.Arg637Gln variant in FHOD3 is a low-penetrant variant, with an intermediate effect, that contributes to the development of HCM in simple heterozygosis, being associated with a more severe phenotype in homozygous carriers.

Role of TBX20 Truncating Variants in Dilated Cardiomyopathy and Left Ventricular Noncompaction

BACKGROUND

Less than 40% of patients with dilated cardiomyopathy (DCM) have a pathogenic/likely pathogenic genetic variant identified. TBX20 has been linked to congenital heart defects; although an association with left ventricular noncompaction (LVNC) and DCM has been proposed, it is still considered a gene with limited evidence for these phenotypes. This study sought to investigate the association between the TBX20 truncating variant (TBX20tv) and DCM/LVNC.

METHODS

TBX20 was sequenced by next-generation sequencing in 7463 unrelated probands with a diagnosis of DCM or LVNC, 22 773 probands of an internal comparison group (hypertrophic cardiomyopathy, channelopathies, or aortic diseases), and 124 098 external controls (individuals from the gnomAD database). Enrichment of TBX20tv in DCM/LVNC was calculated, cosegregation was determined in selected families, and clinical characteristics and outcomes were analyzed in carriers.

RESULTS

TBX20tv was enriched in DCM/LVNC (24/7463; 0.32%) compared with internal (1/22 773; 0.004%) and external comparison groups (4/124 098; 0.003%), with odds ratios of 73.23 (95% CI, 9.90-541.45; P<0.0001) and 99.76 (95% CI, 34.60-287.62; P<0.0001), respectively. TBX20tv was cosegregated with DCM/LVNC phenotype in 21 families for a combined logarythm of the odds score of 4.53 (strong linkage). Among 57 individuals with TBX20tv (49.1% men; mean age, 35.9±20.8 years), 41 (71.9%) exhibited DCM/LVNC, of whom 14 (34.1%) had also congenital heart defects. After a median follow-up of 6.9 (95% CI, 25-75:3.6-14.5) years, 9.7% of patients with DCM/LVNC had end-stage heart failure events and 4.8% experienced malignant ventricular arrhythmias.

CONCLUSIONS

TBX20tv is associated with DCM/LVNC; congenital heart defect is also present in around one-third of cases. TBX20tv-associated DCM/LVNC is characterized by a nonaggressive phenotype, with a low incidence of major cardiovascular events. TBX20 should be considered a definitive gene for DCM and LVNC and routinely included in genetic testing panels for these phenotypes.

Prevalence of cardiac amyloidosis among elderly patients with systolic heart failure or conduction disorders

Objective: Cardiac amyloid infiltration can lead to systolic heart failure (HF) or to conduction disorders (CD). Patients with transthyretin (ATTR) amyloidosis are particularly exposed. We sought to determine the prevalence of ATTR and AL among patients >60 years admitted with CD or unexplained systolic HF and increased wall thickness. Materials and Methods: We studied 143 patients (57% males, 79 ± 9 years) with HF (N = 28) or CD requiring pacemaker implantation (N = 115). In total, 139 (97%) patients (28 with HF and 111 with CD) underwent ^99mTc-DPD scintigraphy to detect ATTR, and 105 (73%; 19 HF and 86 CD) underwent AL screening. Results: Five patients (4%; 95%CI:0-7%) exhibited wild-type ATTR (ATTRwt) amyloidosis, 2 (2%; 95%CI:0-4%) had CD and 3 (11%; 95%CI:0-23%) HF. No patient showed AL. The 2 ATTRwt patients with CD were previously asymptomatic, did not show classical ECG signs and exhibited mild LV hypertrophy with preserved LVEF. By contrast, all ATTRwt patients with HF had ECG and echocardiographic signs of amyloid. During a mean follow-up of 18 ± 11 months, 3(60%) patients with ATTRwt amyloidosis (1 CD and 2 HF) and 14(10.4%) without died. Conclusion: Prevalence of ATTRwt amyloidosis in patients with CD requiring pacemaker is low. Although, additional studies are needed, prevalence seems to be higher in elderly patients with systolic HF.

Genetic Etiology for Alcohol-Induced Cardiac Toxicity

BACKGROUND

Alcoholic cardiomyopathy (ACM) is defined by a dilated and impaired left ventricle due to chronic excess alcohol consumption. It is largely unknown which factors determine cardiac toxicity on exposure to alcohol.

OBJECTIVES

This study sought to evaluate the role of variation in cardiomyopathy-associated genes in the pathophysiology of ACM, and to examine the effects of alcohol intake and genotype on dilated cardiomyopathy (DCM) severity.

METHODS

The authors characterized 141 ACM cases, 716 DCM cases, and 445 healthy volunteers. The authors compared the prevalence of rare, protein-altering variants in 9 genes associated with inherited DCM. They evaluated the effect of genotype and alcohol consumption on phenotype in DCM.

RESULTS

Variants in well-characterized DCM-causing genes were more prevalent in patients with ACM than control subjects (13.5% vs. 2.9%; p = 1.2 ×10^-5), but similar between patients with ACM and DCM (19.4%; p = 0.12) and with a predominant burden of titin truncating variants (TTNtv) (9.9%). Separately, we identified an interaction between TTN genotype and excess alcohol consumption in a cohort of DCM patients not meeting ACM criteria. On multivariate analysis, DCM patients with a TTNtv who consumed excess alcohol had an 8.7% absolute reduction in ejection fraction (95% confidence interval: -2.3% to -15.1%; p < 0.007) compared with those without TTNtv and excess alcohol consumption. The presence of TTNtv did not predict phenotype, outcome, or functional recovery on treatment in ACM patients.

CONCLUSIONS

TTNtv represent a prevalent genetic predisposition for ACM, and are also associated with a worse left ventricular ejection fraction in DCM patients who consume alcohol above recommended levels. Familial evaluation and genetic testing should be considered in patients presenting with ACM.

Prognostic Impact and Predictors of Ejection Fraction Recovery in Patients With Alcoholic Cardiomyopathy

INTRODUCTION AND OBJECTIVES

Recovery of left ventricular ejection fraction (LVEF) has been described in alcoholic cardiomyopathy (ACM) after a period of alcohol withdrawal. Nevertheless, the prognostic impact of LVEF recovery in ACM and its determinants have not been studied. We sought to define the role of LVEF improvement in the long-term outcome of ACM and to identify predictors of LVEF recovery in these patients.

METHODS

We evaluated 101 ACM patients during a median follow-up period of 82 months [interquartile range 36-134].

RESULTS

At latest follow-up, 42 patients (42%) showed substantial LVEF recovery defined as an absolute increase in LVEF ≥ 10% to a final value of ≥ 40%. Patients who recovered LVEF had better outcomes than patients who did not (heart transplant or cardiovascular death 1% vs 30%; P <.001). A QRS with <120ms (OR, 6.68; 95%CI, 2.30-19.41), beta-blocker therapy (OR, 3.01; 95%CI, 1.09-8.28), and the absence of diuretics (OR, 3.35; 95%CI, 1.08-10.42) predicted LVEF recovery in multivariate analysis. Although alcohol cessation did not predict LVEF recovery, none of the patients (n=6) who persisted with heavy alcohol consumption recovered LVEF. The rate of patients who recovered LVEF did not differ between abstainers and moderate drinkers (44% vs 45%; P=.9).

CONCLUSIONS

The LVEF recovery is associated with an excellent prognosis in ACM. Beta-blocker treatment, QRS <120ms and absence of diuretics are independent predictors of LVEF recovery. LVEF recovery is similar in moderate drinkers and abstainers.

Rate and characteristics of urgent hospitalisation in persons with profound intellectual disabilities compared with general population

BACKGROUND

Little is known about the hospitalisation rate of adults with severe/profound intellectual disability (PID) presenting at emergency services or about the appropriateness of hospital admissions in this population. Examining the possible differences in the patterns of hospitalisation between people with PID and those without intellectual disability (ID) may shed light on aspects of health and illness in these patients and may in turn make it possible to differentiate more clearly between mild-moderate ID and PID.

METHODS

After an evaluation of the emergency visits made by adults with PID and by people without ID, patients in both groups requiring one or more hospitalisations were subsequently followed up for 18 months. The appropriateness of the decision to hospitalise was assessed using the ambulatory care-sensitive conditions index.

RESULTS

There were no differences in the proportion of people with PID and controls admitted to hospital after their emergency visit. The median hospital stay was higher for PIDs: 7.5 vs. 4 days for controls. People with PID were admitted more than controls for respiratory reasons and somewhat less for other somatic causes unrelated to the nervous system. There were no admissions for psychiatric causes in the group with PID other than unspecified conduct disorders. There were no differences in other diagnostic groups. The rate of inappropriate admissions was similar in the two study groups.

CONCLUSIONS

In contrast to previous results reported for the group with ID as a whole, patients with PID consulting the emergency service were not admitted to hospital more frequently than the general population nor did they present a higher rate of inappropriate admissions. These results support the utility of maintaining two distinct groups of people with ID: mild-moderate and severe-profound.

Pain underreporting associated with profound intellectual disability in emergency departments

BACKGROUND

Little information is available regarding the visits made by persons with profound intellectual disability (PID) to general hospital emergency departments (ED). This study aims to know whether persons with PID who attend ED are given the same type of diagnoses as people with no such disability.

METHODS

Over a period of 18 months, we gathered data from all non-scheduled visits to an ED by persons with PID to identify the reason for consultation (according to the classification used by the Spanish Society for Emergency Nursing) and the final diagnosis upon discharge. The results were compared with data obtained from a control group of people with no ID who attended an ED for any reason during the same period.

RESULTS

Somatic complaints were the main reason for ED attendance among persons with PID (90% of consultations). These complaints were more often related to the central nervous system than was the case among non-ID patients (16 vs. 4.7%), whereas other kinds of non-central nervous system somatic complaint were less common among persons with PID (74 vs. 91%). A diagnosis implying physical pain was given less often to people with PID than to controls (3 vs. 20%).

CONCLUSIONS

The results suggest that persons with PID are less able to conceptualise and communicate information about their symptoms, especially as regards pain, and that this influences the diagnosis they are given when attending an ED. Professionals working in this environment need to be aware of this possibility so as not to underestimate or overlook such symptoms and the illnesses related to them.