A number sign (#) is used with this entry because of evidence that arrhythmogenic right ventricular dysplasia-14 (ARVD14) is caused by heterozygous mutation in the CDH2 gene (114020) on chromosome 18q12.

Arrhythmogenic right ventricular cardiomyopathy/dysplasia-14 (ARVD14) is characterized by palpitations, chest pain, and presyncope. Electrocardiography shows epsilon waves, T-wave inversion across anterior leads, premature ventricular contractions, ventricular tachycardia, and left bundle branch block. Dilation of the right ventricle with hypokinesia and aneurysmal changes are seen on echocardiography. Cardiac MRI may show fibrofatty infiltration, which has been confirmed by endocardial biopsy in some patients. Sudden death may occur (Mayosi et al., 2017).

For a discussion of genetic heterogeneity of ARVD, see ARVD1 (107970).

Munclinger et al. (2000) reported 12 South African patients, including 8 white patients, 2 black, and 2 of Asian descent, who were diagnosed and followed for ARVD. Two patients were asymptomatic, and were diagnosed only because of familial occurrence. The most frequent symptom was palpitations, and syncope was the presenting symptom in 2 patients. Electrocardiographic (ECG) findings were typical for ARVD and included epsilon waves, inverted T waves in leads V1 to V4, premature ventricular contractions or ventricular tachycardia, and left bundle branch block (LBBB). Spontaneous sustained or nonsustained ventricular tachycardia was documented in 9 patients, and was inducible in all but 1 of the patients who underwent electrophysiologic study. More than 1 morphology of premature ventricular contractions or ventricular tachycardia was observed in 8 of the 9 patients. None had clinical signs of right-sided congestive failure, but both patients who had left ventricular failure died. In addition, there was 1 sudden death (male patient LW), which the authors attributed to a proarrhythmic effect of his cardiac medication. The authors noted that the diagnosis of ARVD was suspected by the referring physician or institution in only 1 patient, and stated that ARVD should be considered in all patients presenting with palpitations, unexplained syncope, or ventricular tachycardia, especially if they are young and their symptoms are associated with exertion or excitement. The authors concluded that ARVD occurs in the spectrum of cardiac disorders among all groups of the South African population, and incurs significant morbidity and mortality.

Matolweni et al. (2006) studied a 3-generation South African family with ARVD. The proband (III-2) presented at age 16 years with palpitations associated with ventricular tachycardia and left bundle branch morphology consistent with a right ventricular (RV) origin. ECG showed an epsilon wave in lead V1 and inverted T waves in V1 to V3, and echocardiogram revealed a markedly dilated RV with reduced systolic function. He died suddenly at age 22 despite treatment with various antiarrhythmic drugs. His sister (III-3) displayed similar clinical features, and died suddenly at age 24 years. Their mother (II-2) had died of brain cancer at age 34 years, and their father was unavailable for study. A male cousin (III-4) presented with chest pain and palpitations at age 23 years, and 24-hour Holter monitoring showed frequent ventricular ectopy. Echocardiography and angiography revealed global RV dilation, with changes suggestive of increased fat in the RV free wall; cardiac MRI indicated complete fatty replacement in some areas, which was confirmed by endocardial biopsy. Electrophysiologic analysis demonstrated inducible nonsustained monomorphic ventricular tachycardia with LBBB and right axis deviation. Family screening showed structural and ECG abnormalities in the cousin's 2 sibs (III-6 and III-7), and their mother (II-4) had an abnormal ECG with T-wave inversion in leads V1 to V3, compatible with a diagnosis of ARVD with partial penetrance. Their mother's sister (II-7) had palpitations and T-wave inversion in V1 to V3, as well as mild RV dilation, aneurysmal change, and wall motion abnormality on cardiac MRI. Her daughter (III-9) appeared to have similar MRI abnormalities. The authors noted that ARVD in this family showed variable expression, with a tendency for severe manifestations in the third generation.

Mayosi et al. (2017) restudied the 3-generation South African family (ACM2) with ARVD that was previously described by Matolweni et al. (2006) and originally phenotyped by Munclinger et al. (2000) (the proband appears to have been designated 'patient LW' in Munclinger et al., 2000). Reexamination of 2 family members by Mayosi et al. (2017) resulted in their reclassification as unaffected: the first was patient III-7 of Matolweni et al. (2006) (designated III-6 by Mayosi et al. (2017)), who was asymptomatic with normal ECG, echocardiogram, cardiac MRI, and 24-hour ECG monitoring. In addition, review of clinical records of patient III-9 of Matolweni et al. (2006) (designated III-8 by Mayosi et al. (2017)) showed that although she had an episode of syncope in the past, ventricular tachycardia was not induced on 2 separate electrophysiologic studies, nor were any episodes recorded on her implantable cardioverter defibrillator, which had been inserted prophylactically at the patient's request. Her cardiac MRI study, which was originally reported as showing mild RV dilation with wall motion change and aneurysmal abnormality similar to her mother's, was now interpreted as being within normal limits.

Mayosi et al. (2017) also reported an unrelated South African man (ACM11) who presented at age 15 with palpitations and presyncope associated with ventricular tachycardia. The diagnosis of ARVD was made based on the presence of T-wave inversion from V1 through V6 on ECG, late potentials on signal-averaged ECG, sustained ventricular tachycardia with LBBB (superior axis), and structural changes (marked RV dilatation and multiple aneurysms of the RV free wall) seen on echocardiography, angiography, and cardiac MRI. Histologic examination of endomyocardial biopsy from the RV showed fibrofatty replacement of cardiomyocytes. He underwent placement of an implantable cardioverter/defibrillator.

The transmission pattern of ARVD14 in the family studied by Mayosi et al. (2017) and originally reported by Munclinger et al. (2000) and Matolweni et al. (2006) was consistent with autosomal dominant inheritance.

In 2 affected cousins from a 3-generation South African family (ACM2) with ARVD, Mayosi et al. (2017) performed whole-exome sequencing (WES) and identified heterozygosity for a missense mutation in the CDH2 gene (Q229P; 114020.0001) that segregated fully with disease in the family. Screening a cohort of 73 patients with ARVD who were negative for mutation in known ARVD-associated genes, the authors identified 1 proband of South African ancestry (ACM11) who was heterozygous for another missense mutation in CDH2 (D407N; 114020.0002). The authors suggested that CDH2 is an uncommon cause of ARVD (2.7% in their series of 74 ARVD probands).

In a 3-generation South African family (ACM2) segregating autosomal dominant ARVD, Matolweni et al. (2006) performed linkage analysis, which excluded known ARVD loci except for ARVD6 (604401) on chromosome 10p12-p14. Two-point lod scores for genotyping of 15 markers spanning the ARVD6 locus were highly suggestive of linkage in the family (D10S191 and D10S1653, Z = 2.93 for both at theta = 0). The authors stated that although the lod score did not reach statistical significance, lod score simulation analysis showed that 2.93 was the highest lod score that could be obtained for the pedigree. Recombination events narrowed the critical region to an approximately 2.9-Mb interval between markers D10S1707 and D10S1477; analysis of 3 candidate genes in the region showed no pathogenic mutations.

Mayosi et al. (2017) reclassified as unaffected 2 members of the family (ACM2) described by Matolweni et al. (2006), and reevaluated the genetic linkage analysis. Mayosi et al. (2017) concluded that it was highly probable that the phenotypic misattributions of 2 family members had introduced significant bias into the results obtained. After WES in 2 affected cousins (see MOLECULAR GENETICS), the authors performed parametric linkage analysis prioritizing regions with lod scores greater than 2, and found that none of the 13 genes with shared variants from the WES data were located in those regions, except for the CDH2 gene on chromosome 18.