Evaluation of Clinical Practices Related to Variants of Uncertain Significance Results in Inherited Cardiac Arrhythmia and Inherited Cardiomyopathy Genes.

BACKGROUND: Increasing use of genetic tests have identified many variants of uncertain significance (VUS) in genes associated with inherited arrhythmias and cardiomyopathies. Evaluation of clinical practices, including medical management recommendations for VUS patients and their families, is important to prevent over- or under-treatment that may result in morbidity or mortality. The purpose of this study is to describe practices related to VUS results including information and medical management recommendations providers give patients and their families. METHODS: An anonymous online survey was distributed to genetic counselors (GCs) and cardiologists who have seen at least one patient for inherited arrhythmias or cardiomyopathies. The survey explored providers' confidence in counseling, explanation of VUSs, topics covered before and after genetic testing, and clinical recommendations using a hypothetical scenario maximizing uncertainty with an unclear clinical and molecular diagnosis. Descriptive statistics were calculated, and median confidence and likelihood of making various medical recommendations were compared across provider type. RESULTS: Providers (N=102) who completed the survey included 29 cardiovascular GCs, 50 GCs from other specialties, and 23 cardiologists. GCs feel more confident than cardiologists counseling about VUS results (P<0.001); while both cardiovascular GCs and cardiologists feel more confident than other GCs in providing input regarding medical management recommendations (P=0.001 and P=0.01, respectively). Cardiologists were more likely than cardiac GCs to recommend clinical testing for family members even though testing in the scenario is expected to be uninformative. CONCLUSIONS: These findings illustrate how the expertise of different providers may impact decision processes, suggesting the need for interdisciplinary clinics to optimize care for challenging cases.

Spectrum of elastin sequence variants and cardiovascular phenotypes in 49 patients with Williams-Beuren syndrome.

Haploinsufficiency of the elastin gene (ELN) on 7q11.23 is responsible for supravalvular aortic stenosis (SVAS) and other arteriopathies in patients with Williams-Beuren syndrome (WBS). These defects occur with variable penetrance and expressivity, but the basis of this is unknown. To determine whether DNA variations in ELN could serve as genetic modifiers, we sequenced the 33 exons and immediately surrounding sequence of the ELN gene (9,455 bp of sequence) in 49 DNAs from patients with WBS and compared cardiovascular phenotypes. Four missense, and four novel intronic variants were identified from a total of 24 mostly intronic single nucleotide variations and one indel. Two missense changes were present in one patient each, one published, p.Gly610Ser in exon 27 (MAF, 0.003) and one novel, p.Cys714Tyr, in exon 33 (MAF, 0.001), were rare in the general population. To identify a statistical association between the variants identified here and cardiovascular phenotypes a larger cohort would be needed.

Dextrocardia, atrial septal defect, severe developmental delay, facial anomalies, and supernumerary ribs in a child with a complex unbalanced 8;22 translocation including partial 8p duplication.

We report on a child with dextrocardia, atrial septal defect (ASD), severe developmental delay, hypotonia, 13 pairs of ribs, left preauricular choristoma, hirsutism, and craniofacial abnormalities. Prenatal cytogenetic evaluation showed karyotype 46,XY,?dup(8p)ish del(8)pter. Postnatal array CGH demonstrated a 6.8 Mb terminal deletion at 8p23.3-p23, an interstitial 31.1 Mb duplication within 8p23.1-p11, and a terminal duplication of 0.24 Mb at 22q13.33, refining the karyotype to 46,XY,der(8)dup(8)(p23.1p11.1)t(8;22)(p23.1;q13.1).ish der(8)dup(8)(p23.1p11.1)t(8;22)(p23.1;q13.1) (D8S504-,MS607 + ,ARSA + ,D8Z1 + , RP115713 + +). Previous reports of distal 8p deletion, 8p duplication, and distal 22q duplication have shown similar manifestations, including congenital heart disease, intellectual impairment, and multiple minor anomalies. We correlate the patient's clinical findings with these particular areas of copy number. This case study supports the use of aCGH to identify subtle chromosomal rearrangement in infants with cardiac malformation as their most significant or only apparent birth defect. Additionally, it illustrates why aCGH is essential in the description of chromosome rearrangements, even those seemingly visible via routine karyotype. This method shows that there is often greater complexity submicroscopically, essential to an adequate understanding of a patient's genotype and phenotype.