Understanding variants of uncertain significance in the era of multigene panels: Through the eyes of the patient.

Variants of uncertain significance (VUSs) are often disclosed to patients despite ambiguous association with disease risk and lack of clinical actionability. It is important to understand how patients understand a VUS result, but few studies have assessed this. Our qualitative study explored patient recall, reaction to, and interpretation of a VUS in the context of multigene panels. We conducted 11 semi-structured phone interviews with adults who had a VUS identified on multigene panel testing in a hereditary oncology clinic, with questions focusing on the VUS result, personal and family history, and motivations for and expectations of genetic testing. Transcripts were coded iteratively, using both deductive and inductive codes. Overall, participants usually recalled that they had a VUS, despite variation in the vocabulary used. Participants responded both emotionally and intellectually to receiving information about having a VUS, which was often a result of their expectations and motivations prior to testing. Overall, participants understood the lack of clinical significance of a VUS, yet often interpreted the etiologic significance of a VUS within the context of the personal and family history. Our study provides insight into a process by which patients translate uncertain genetic testing results into a construct that fits within their current belief framework and which may be facilitated by a genetic counselor.

Clinically impactful differences in variant interpretation between clinicians and testing laboratories: a single-center experience.

PurposeTo describe the frequency and nature of differences in variant classifications between clinicians and genetic testing laboratories.MethodsRetrospective review of variants identified through genetic testing ordered in routine clinical care by clinicians in the Stanford Center for Inherited Cardiovascular Disease. We compared classifications made by clinicians, the testing laboratory, and other laboratories in ClinVar.ResultsOf 688 laboratory classifications, 124 (18%) differed from the clinicians' classifications. Most differences in classification would probably affect clinical care of the patient and/or family (83%, 103/124). The frequency of discordant classifications differed depending on the testing laboratory (P < 0.0001) and the testing laboratory's classification (P < 0.00001). For the majority (82/124, 66%) of discordant classifications, clinicians were more conservative (less likely to classify a variant pathogenic or likely pathogenic). The clinicians' classification was discordant with one or more submitter in ClinVar in 49.1% (28/57) of cases, while the testing laboratory's classification was discordant with a ClinVar submitter in 82.5% of cases (47/57, P = 0.0002).ConclusionThe clinical team disagreed with the laboratory's classification at a rate similar to that of reported disagreements between laboratories. Most of this discordance was clinically significant, with clinicians tending to be more conservative than laboratories in their classifications.

Prevalence and Outcomes of Primary Left Ventricular Dysfunction in Marfan Syndrome.

Even in the absence of significant valvular disease, patients with Marfan syndrome (MFS) have evidence of impaired left ventricular (LV) performance, suggestive of a primary cardiomyopathy. However, the true prevalence and long-term outcomes of this disease process remain largely unknown. We performed a retrospective analysis of all adult patients with confirmed MFS followed at Stanford Health Care. Those with significant valvular regurgitation, coronary artery disease, or previous cardiac surgery were excluded. LV systolic dysfunction was defined as a LV ejection fraction (LVEF) <55% on transthoracic echocardiography. A total of 753 patients with confirmed MFS were followed up over a median duration of 8 years (interquartile range 4 to 13). Of those, 241 patients (53% women, 71% White) met inclusion criteria and comprised the study cohort. LV systolic dysfunction was present in 30 patients (12%), with a median age of onset of 25 years (interquartile range 19 to 37), median EF of 52% (interquartile range 48 to 54), and evidence of clinical heart failure (New York Heart Association functional class ≥II) in 10% of patients. LV systolic dysfunction was more common in patients with larger aortic root diameters (≥4.0 cm: Odds ratio = 4.5, 95% confidence interval = 1.2 to 17.1) but was not associated with other cardiovascular manifestations of MFS or traditional atherosclerotic risk factors. In conclusion, apart from significant valvular pathology, LV systolic dysfunction was prevalent in MFS from a young age, suggestive of a primary cardiomyopathy. LV dysfunction was typically mild and subclinical and occurred more commonly in patients with more pronounced aortopathies.

Genetic screening in the Persian Jewish community: A pilot study.

PURPOSE: Israeli investigators have identified several relatively frequent disorders due to founder point mutations in Persian (Iranian) Jews, who, for nearly three centuries up to the Islamic Revolution of 1979, were completely isolated reproductively. METHODS: Using a community-based model previously employed with Tay-Sachs disease prevention, we developed a pilot program for the Persian Jewish community of greater Los Angeles. We screened for mutations responsible for four relatively frequent autosomal recessive conditions in Persian Jews in which effective interventions are available for each: Pseudocholinesterase deficiency (butyryl cholinesterase deficiency); Congenital hypoaldosteronism (corticosterone methyl oxidase II); Autoimmune polyendocrinopathy (autoimmune regulatory element); and Hereditary Inclusion Body myopathy. RESULTS: One thousand individuals volunteered. Mutations were assessed in saliva-derived DNA and were positive for 121/1000 butyryl cholinesterase deficiency; 92/1000 Hereditary Inclusion Body myopathy; 38/1000 corticosterone methyl oxidase II; and 37/1000 autoimmune regulatory element. Ten homozygous individuals (9 butyryl cholinesterase deficiency and 1 Hereditary Inclusion Body myopathy) and 10 "at-risk" couples (seven for butyryl cholinesterase deficiency and one each for the other three disorders) were identified. These frequencies are comparable with those in Israel and indicate an extraordinary level of inbreeding, as anticipated. CONCLUSIONS: A carefully planned effort can be delivered to an "increased risk" community if detailed attention is given to planning and organization. However, availability of an effective intervention for those found to be "at-risk" or possibly affected, is essential before embarking.

Quantitative proteomics reveal lineage-specific protein profiles in iPSC-derived Marfan syndrome smooth muscle cells.

Marfan syndrome (MFS) is a connective tissue disorder caused by mutations in the FBN1 gene that produces wide disease phenotypic variability. The lack of ample genotype-phenotype correlation hinders translational study development aimed at improving disease prognosis. In response to this need, an induced pluripotent stem cell (iPSC) disease model has been used to test patient-specific cells by a proteomic approach. This model has the potential to risk stratify patients to make clinical decisions, including timing for surgical treatment. The regional propensity for aneurysm formation in MFS may be related to distinct smooth muscle cell (SMC) embryologic lineages. Thus, peripheral blood mononuclear cell (PBMC)-derived induced pluripotent stem cells (iPSC) were differentiated into lateral mesoderm (LM, aortic root) and neural crest (NC, ascending aorta/transverse arch) SMC lineages to model MFS aortic pathology. Isobaric Tags for Relative and Absolute Quantitation (iTRAQ) proteomic analysis by tandem mass spectrometry was applied to profile LM and NC iPSC SMCs from four MFS patients and two healthy controls. Analysis revealed 45 proteins with lineage-dependent expression in MFS patients, many of which were specific to diseased samples. Single protein-level data from both iPSC SMCs and primary MFS aortic root aneurysm tissue confirmed elevated integrin αV and reduced MRC2 in clinical disease specimens, validating the iPSC iTRAQ findings. Functionally, iPSC SMCs exhibited defective adhesion to a variety of extracellular matrix proteins, especially laminin-1 and fibronectin, suggesting altered cytoskeleton dynamics. This study defines the aortic embryologic origin-specific proteome in a validated iPSC SMC model to identify novel protein markers associated with MFS aneurysm phenotype. Translating iPSC findings into clinical aortic aneurysm tissue samples highlights the potential for iPSC-based methods to model MFS disease for mechanistic studies and therapeutic discovery in vitro.

Genetics and Precision Medicine: Heritable Thoracic Aortic Disease.

Heritable thoracic aortic disease (HTAD) can have life-threatening consequences if not diagnosed early. Affected individuals and at-risk family members benefit from both cardiology and genetic evaluations, including genetic testing. Important information can be obtained through family history, medical history, and genetic testing to help guide management and assess risk. A genetic diagnosis can guide cardiovascular management (type and frequency of vascular imaging, timing of surgical intervention), risk assessment for arterial aneurysm/dissection, evaluation of nonvascular features, and familial testing.

Finding missed cases of familial hypercholesterolemia in health systems using machine learning.

Familial hypercholesterolemia (FH) is an underdiagnosed dominant genetic condition affecting approximately 0.4% of the population and has up to a 20-fold increased risk of coronary artery disease if untreated. Simple screening strategies have false positive rates greater than 95%. As part of the FH Foundation's FIND FH initiative, we developed a classifier to identify potential FH patients using electronic health record (EHR) data at Stanford Health Care. We trained a random forest classifier using data from known patients (n = 197) and matched non-cases (n = 6590). Our classifier obtained a positive predictive value (PPV) of 0.88 and sensitivity of 0.75 on a held-out test-set. We evaluated the accuracy of the classifier's predictions by chart review of 100 patients at risk of FH not included in the original dataset. The classifier correctly flagged 84% of patients at the highest probability threshold, with decreasing performance as the threshold lowers. In external validation on 466 FH patients (236 with genetically proven FH) and 5000 matched non-cases from the Geisinger Healthcare System our FH classifier achieved a PPV of 0.85. Our EHR-derived FH classifier is effective in finding candidate patients for further FH screening. Such machine learning guided strategies can lead to effective identification of the highest risk patients for enhanced management strategies.

Echocardiographic findings in patients with spontaneous CSF leak.

The presence of cardiovascular abnormalities in patients with spontaneous cerebrospinal fluid (CSF) leaks are not well-documented in the literature, as cardiovascular evaluation is not generally pursued if a patient does not exhibit additional clinical features suggesting an inherited connective tissue disorder. We aimed to assess this association, enrolling a consecutive group of 50 patients referred for spinal CSF leak consultation. Through echocardiographic evaluation and detailed medical history, we estimate that up to 20% of patients presenting with a spontaneous CSF leak may have some type of cardiovascular abnormality. Further, the increase in prevalence of aortic dilatation in our cohort was statistically significant in comparison to the estimated population prevalence. This supports a clinical basis for echocardiographic screening of these individuals for cardiovascular manifestations that may have otherwise gone unnoticed or evolved into a more severe manifestation.

Connective tissue spectrum abnormalities associated with spontaneous cerebrospinal fluid leaks: a prospective study.

We aimed to assess the frequency of connective tissue abnormalities among patients with cerebrospinal fluid (CSF) leaks in a prospective study using a large cohort of patients. We enrolled a consecutive group of 50 patients, referred for consultation because of CSF leak. All patients have been carefully examined for the presence of connective tissue abnormalities, and based on findings, patients underwent genetic testing. Ancillary diagnostic studies included echocardiography, eye exam, and histopathological examinations of skin and dura biopsies in selected patients. We identified nine patients with heritable connective tissue disorders, including Marfan syndrome, Ehlers-Danlos syndrome and other unclassified forms. In seven patients, spontaneous CSF leak was the first noted manifestation of the genetic disorder. We conclude that spontaneous CSF leaks are associated with a spectrum of connective tissue abnormalities and may be the first noted clinical presentation of the genetic disorder. We propose that there is a clinical basis for considering spontaneous CSF leak as a clinical manifestation of heritable connective tissue disorders, and we suggest that patients with CSF leaks should be screened for connective tissue and vascular abnormalities.

Vascular and connective tissue anomalies associated with X-linked periventricular heterotopia due to mutations in Filamin A.

Mutations conferring loss of function at the FLNA (encoding filamin A) locus lead to X-linked periventricular nodular heterotopia (XL-PH), with seizures constituting the most common clinical manifestation of this disorder in female heterozygotes. Vascular dilatation (mainly the aorta), joint hypermobility and variable skin findings are also associated anomalies, with some reports suggesting that this might represents a separate syndrome allelic to XL-PH, termed as Ehlers-Danlos syndrome-periventricular heterotopia variant (EDS-PH). Here, we report a cohort of 11 males and females with both hypomorphic and null mutations in FLNA that manifest a wide spectrum of connective tissue and vascular anomalies. The spectrum of cutaneous defects was broader than previously described and is inconsistent with a specific type of EDS. We also extend the range of vascular anomalies associated with XL-PH to included peripheral arterial dilatation and atresia. Based on these observations, we suggest that there is little molecular or clinical justification for considering EDS-PH as a separate entity from XL-PH, but instead propose that there is a spectrum of vascular and connective tissues anomalies associated with this condition for which all individuals with loss-of-function mutations in FLNA should be evaluated. In addition, since some patients with XL-PH can present primarily with a joint hypermobility syndrome, we propose that screening for cardiovascular manifestations should be offered to those patients when there are associated seizures or an X-linked pattern of inheritance.

Visceroptosis of the bowel in the hypermobility type of Ehlers-Danlos syndrome: presentation of a rare manifestation and review of the literature.

Gastrointestinal complications are common in patients with Ehlers-Danlos syndrome, affecting up to 50% of individuals depending on the subtype. The spectrum of gastrointestinal manifestations is broad and ranges from life threatening spontaneous perforation of the visceral organs to a more benign functional symptoms. Here we describe the clinical and radiographic manifestations of visceroptosis of the bowel, a rare complication of Ehlers-Danlos syndrome that is characterized by prolapse of abdominal organs below their natural position. We further review the literature on gastrointestinal complications in the different forms of Ehlers-Danlos syndrome.

A 785kb deletion of 3p14.1p13, including the FOXP1 gene, associated with speech delay, contractures, hypertonia and blepharophimosis.

We report a child with a 785kb deletion of the 3p14.1p13 region including the genes FOXP1, EIF4E3, PROK2, GPR27 resulting in speech delay, contractures, hypertonia and blepharophimosis. FOXP1 and FOXP2 are transcription factors containing a polyglutamine tract and a forkhead DNA binding domain. They both play a role in the developing human foregut and brain [W. Shu, M.M. Lu, Y. Zhang, P. Tucker, D. Zhou, E.E. Morrisey, Foxp2 and Foxp1 cooperatively regulate lung and esophagus development, Development 134 (2007) 1991-2000, E. Spiteri, G. Konopka, G. Coppola, J. Bomar, M. Oldham, J. Ou, et al. Identification of the transcriptional targets of FOXP2, a gene linked to speech and language, in developing human brain, Am. J. Hum. Genet. 81 (2007) 1144-1157, S. Tamura, Y. Morikawa, H. Iwanishi, T. Hisaoka, E. Senba. Expression pattern of the winged-helix/forkhead transcription factor Foxp1 in the developing central nervous system, Gene Expr. Patterns. 3 (2003) 193-197.]. Mutations in FOXP2 are known to cause severe speech and language abnormalities [C.S.L. Lai, S.E. Fisher, J.A. Hurst, F. Vargha-Khadem, A.P. Monaco, A forkhead-domain gene is mutated in a severe speech and language disorder, Nature 413 (2001) 519-523.] in humans and animals. It has been suggested that overlap of FOXP1 and FOXP2 expression in the songbird and human brain may indicate that mutations in FOXP1 would also result in speech and language abnormalities. The roles of EIF4E3, PROK2 and GPR27 are also evaluated.