C. Alexander Valencia

C. Alexander Valencia

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C. Alexander Valencia

C Alexander Valencia, PhD, 45925 Horseshoe Drive, Suite 170, Sterling, VA 20166

Research Focus & Metrics

Academic Career Length

23Years (2004-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 June 2020 in The Journal of Molecular Diagnostics
Verified
Journal Article
Open access
ACAlka Chaubey
Alka Chaubey
SSSuresh Shenoy
Suresh Shenoy
AMAbhinav Mathur
Abhinav Mathur
ZMZeqiang Ma
Zeqiang Ma
CVC. Alexander Valencia
C. Alexander Valencia
MHMadhuri R. Hegde
Madhuri R. Hegde
DNA copy number variants (CNVs) account for approximately 300 Mb of sequence variation in the normal human genome. Significant numbers of pathogenic CNVs contribute toward human genetic disorders. Recent studies suggest a higher diagnostic and clinical significance of low-pass genome sequencing (LP-GS) compared with chromosomal microarrays (CMAs). The performance metrics of the 5X LP-GS was compared with CMA to validate a low-cost and high-throughput method. LP-GS test performed on 409 samples (including 78 validation and 331 clinical) was evaluated using American College of Medical Genetics and Genomics guidelines. The CNV accuracy, precision, specificity, and sensitivity were calculated to be 100% for all previously characterized CNVs by CMA. Samples (n = 6) run at both approximately 30X GS and approximately 5X GS (LP-GS) average depth detected a concordance of 89.43% to 91.8% and 77.42% to 89.86% for overall single-nucleotide variants and insertions/deletions, respectively. In the 331 clinical samples, 17.2% each were classified as pathogenic/likely pathogenic and uncertain clinical significance. In addition, several cases with pathogenic CNVs were detected that were missed by CMA. This study demonstrates that LP-GS (5X GS) was able to reliably detect absence of heterozygosity, microdeletion/microduplication syndromes, and intragenic CNVs with higher coverage and resolution over the genome. Because of lower cost, higher resolution, and greater sensitivity of this test, our study in combination with other reports could be used in an evidence-based review by professional societies to recommend replacing CMAs.

23 September 2004 in Acta Crystallographica Section D Structural Biology
Verified
Journal Article
Closed access
PDF file
GSGerlind Sulzenbacher
Gerlind Sulzenbacher
VRVéronique Roig-Zamboni
Véronique Roig-Zamboni
FPFabienne Pagot
Fabienne Pagot
SGSacha Grisel
Sacha Grisel
ASAurelia Salomoni
Aurelia Salomoni
CCChristian Cambillau
Christian Cambillau

21 November 2020 in American Journal of Medical Genetics Part C: Seminars in Medical Genetics
Verified
Journal Article
Open access
PDF file
RMRafael Mena
Rafael Mena
EMEsperanza Mendoza
Esperanza Mendoza
MPMaria Gomez Peña
Maria Gomez Peña
CVC. Alexander Valencia
C. Alexander Valencia
EUEhsan Ullah
Ehsan Ullah
CPCarlos E. Prada
Carlos E. Prada
There is a shortage of genetics providers worldwide and access is limited to large academic centers. Telemedicine programs can facilitate access to genetic services to patients living in remote locations. The goal of this study was to improve access to genetic services in the Dominican Republic by creating a partnership model between a pediatrician and geneticist. This approach has been used within the United States but not in the setting of two different countries, healthcare system, and cultures. Patients were referred to the Centro de Obstetricia y Ginecologia program if a syndromic or genetic etiology was suspected by their local provider. Pediatrician first evaluated all patients prior to telemedicine appointment to review family and medical history. All genetic visits were scheduled within 2 weeks of referral in collaboration with telehealth program at Cincinnati Children's Hospital Medical Center. A total of 66 individuals were evaluated during a period of 5 years. Fifty‐seven individuals underwent genetic studies, and a molecular diagnosis was made in 39 individuals. Exome sequencing was the most common first line test when differential diagnosis was broad (n = 40). The most common inheritance was autosomal recessive in 15 individuals, followed by 13 individuals with autosomal dominant disorders, 7 individuals X‐linked disorders, and 4 individuals with chromosomal abnormalities. This study provides data to support utility of geneticist and pediatrician partnership to provide outreach telemedicine diagnostics and management services for rare diseases in an international setting.

30 August 2021 in Microbiology & Infectious Diseases
Verified
Journal Article
Open access
DBDavid Baugher
David Baugher
ALAlexander W Larsen
Alexander W Larsen
YCYuan Chen
Yuan Chen
CICrystal R. Icenhour
Crystal R. Icenhour
CVC Alexander Valencia
C Alexander Valencia