Variants of uncertain significance in prenatal microarrays: a retrospective cohort study.

OBJECTIVE: To categorise the variants of uncertain significance found with prenatal chromosomal microarray and determine the proportion of such variants that are associated with a well-known phenotype in order to establish how often they remain truly of uncertain significance. DESIGN: Retrospective cohort study. SETTING: The University of California, San Francisco. POPULATION: All patients with a variant of uncertain significance on prenatal microarray between 2014 and 2018. METHODS: Each variant was classified as a copy number variant that (a) contains Online Mendelian Inheritance in Man (OMIM)-annotated disease-causing genes ('OMIM morbid genes'); (b) confers autosomal recessive carrier status; (c) is associated with incomplete penetrance; (d) is >1 Mb in size without OMIM morbid genes; (e) demonstrates mosaicism; or (f) contains significant regions of homozygosity. For each variant of uncertain significance, we examined the existing literature to determine whether the predicted phenotype(s) was known. MAIN OUTCOME MEASURE: Prevalence and classification of variants and how much information is available regarding the likelihood of an affected phenotype. RESULTS: Of 970 prenatal microarrays, 55 (5.8%) had at least one variant of uncertain significance. The most common were copy number variants containing OMIM morbid genes (36.8%). In all, 48 (84.2%) were associated with a known phenotype; 55 (96.5%) had data available regarding the likelihood of an affected phenotype. CONCLUSIONS: The prevalence of variants of uncertain significance with prenatal microarray was 5.8%. In the large majority of cases, data were available regarding the predicted phenotype. TWEETABLE ABSTRACT: Variants of uncertain significance occur in 5.8% of prenatal microarrays. In the overwhelming majority of cases, outcome information is available.

Cytomegalovirus disease and infection in lung transplant recipients in the setting of planned indefinite valganciclovir prophylaxis.

BACKGROUND: The optimal method of both predicting and preventing cytomegalovirus (CMV) disease in lung transplant recipients remains unclear. In particular, the most appropriate duration of CMV prophylaxis post transplant is unresolved. We report herein our experience with a planned indefinite regimen of valganciclovir prophylaxis and monitoring of quantitative CMV load in bronchoalveolar lavage (BAL) fluid. METHODS: We performed a single-center observational study with both prospective and retrospective components. The included patients (n = 128) received a planned regimen of indefinite valganciclovir prophylaxis post transplant, regardless of donor (D)/recipient (R) CMV serostatus. Real-time polymerase chain reaction assay for detection of CMV in BAL was prospectively performed over a 1-year period. Clinical data were reviewed retrospectively; median follow-up was 24.8 months (range 1-93 months). RESULTS: Sixty-five patients (50.6%) discontinued valganciclovir prophylaxis, either temporarily or permanently, with a primary cause of mild leukopenia. Six cases of CMV disease were identified (4.7%), with no significant difference between those who were on continuous prophylaxis or not (4.6% vs. 4.9%; P = non-significant [ns]). However, those who discontinued prophylaxis showed an increased incidence of laboratory-detected CMV infection (40.7% vs. 12.7%; P = 0.001). High-risk D+/R- patients did not demonstrate a significantly increased incidence of CMV disease (8.1% vs. 3.3% other serotypes; P = ns). Three patients (2.3%) developed valganciclovir-resistant CMV disease. Molecular detection of CMV in BAL fluid was significantly more sensitive than shell vial culture. However, BAL CMV viral load was not predictive of subsequent disease development. CONCLUSIONS: Extended valganciclovir prophylaxis for all lung transplant recipients led to a low incidence of CMV disease and resistance. In such low-incidence populations, routine quantitation of CMV in BAL did not confer significant clinical benefit over non-quantitative methods in prediction of CMV disease onset.