Ebstein anomaly is characterized by downward displacement of variable severity of the tricuspid valve into the right ventricle. The valve leaflets may be dysplastic, and a variable portion of the proximal part of the right ventricle is in ... Ebstein anomaly is characterized by downward displacement of variable severity of the tricuspid valve into the right ventricle. The valve leaflets may be dysplastic, and a variable portion of the proximal part of the right ventricle is in continuity with the right atrium ('atrialized'), because of the abnormally positioned tricuspid valve. The severity of this defect includes a spectrum ranging from severe disturbance in fetal and neonatal life to virtually asymptomatic survival to adult life. Associated extracardiac anomalies in the setting of chromosomal or mendelian disorders occur in about 20% of patients with Ebstein anomaly. Nonsyndromic Ebstein anomaly can occur as a sporadic or a familial defect (summary by Digilio et al., 2011).
Gouffault et al. (1960) found Ebstein malformation in 1 sib and a comparable deformity of the mitral valve in a sister. The same combination of Ebstein anomaly in 1 sib and comparable mitral anomaly in another was apparently ... Gouffault et al. (1960) found Ebstein malformation in 1 sib and a comparable deformity of the mitral valve in a sister. The same combination of Ebstein anomaly in 1 sib and comparable mitral anomaly in another was apparently present in the family reported by Yamauchi and Cayler (1964). Gueron et al. (1966) described a brother and sister with Ebstein anomaly, a congenital malformation of the heart that consists of downward placement of the tricuspid valve such that part of the right ventricle becomes incorporated into the pretricuspid chamber. Associated deformity of the tricuspid leaflets and defect of the atrial septum are frequent. Donegan et al. (1968) found Ebstein anomaly in a 6-year-old boy and his maternal uncle. The Ebstein anomaly predisposes to right bundle branch block, preexcitation, and an increased risk of sudden cardiac death. Atrial fibrillation occurs in about one-third of patients with Ebstein anomaly. Pierard et al. (1985) reported atrial standstill in father and son with Ebstein anomaly. McIntosh et al. (1992) diagnosed severe Ebstein anomaly prenatally in 2 sisters born of Sri Lankan parents who were first cousins once removed. Digilio et al. (2011) studied 44 consecutive patients with Ebstein anomaly presenting to 2 pediatric cardiology centers. In 12 (27%) of the 44 patients, Ebstein anomaly was part of a syndrome, and 7 of those patients were diagnosed with distinct disorders, including CHARGE syndrome (214800) in 2, and VACTERL association (see 192350), Noonan syndrome (163950), Kabuki syndrome (147920), Holt-Oram syndrome (142900), and Cornelia de Lange syndrome (see 122470) in 1 each. Of the 32 patients with nonsyndromic Ebstein anomaly, 10 (31%) had additional congenital heart defects (CHDs), including 7 atrial septal defects, 2 ventricular septal defects, 2 pulmonary stenoses, 1 dextrocardia, 1 aortic coarctation, and 1 patent ductus arteriosus; 1 of the patients with ASD also had a Wolff-Parkinson-White cardiac conduction anomaly (WPW; see 194200). The remaining 22 patients had Ebstein defect alone; 1 of these patients also had WPW. Familial recurrence of CHD was seen in 1 family, in which a mother with nonsyndromic Ebstein anomaly had a son with persistence of left ventricular noncompaction (see 604169).
In 28 patients with nonsyndromic Ebstein anomaly, Digilio et al. (2011) screened the candidate genes GATA4 (600576) and NKX2.5 (600584), but did not find any mutations.