Brenda Lomax

University of Edinburgh

Author Statistics

Papers

Citation

H-Index

i-10 index

Research Trends

Author Order

Document Type

Co-Authors

Irene Barrett

Trinity College Dublin

Dagmar K. Kalousek

University of British Columbia

Patrice Eydoux

University of British Columbia

Jia‐Chi Wang

City Of Hope National Medical Center

V.S. Lestou

University of British Columbia

Brian D. Kuchinka

University of British Columbia

Karen J. Harrison

Queen's University

Patrick MacLeod

University of British Columbia

Siu‐Li Yong

University of British Columbia

Steven S. Tang

University of Kentucky

Cooperative Institutions

University of British Columbia

University Hospitals Birmingham NHS Foundation Trust

Southern Health NHS Foundation Trust

British Columbia Children's Hospital

Children's & Women's Health Centre of British Columbia

University of Edinburgh

Colchester Hospital

Gloucestershire Health and Care NHS Foundation Trust

BC Cancer Agency

University College London

Author Statistics

Papers

Citation

H-Index

i-10 index

Research Field

Molecular breakpoint mapping of 6q11‐q14 interstitial deletions in seven patients

American Journal of Medical Genetics Part A (2009)

Jia‐Chi Wang Linda Dang Brenda Lomax Lesley Turner Mary Shago

Interstitial deletions involving 6q11-q14 have been reported in less than 20 patients, with the breakpoints studied by G-banding alone. We report on seven patients with 6q11-q14 interstitial deletions of variable size. The breakpoints were studied by G-banding, dual-color BAC-FISH and SNP array. The results showed the molecular breakpoints differed significantly from the ones obtained from G-banding. The breakpoints studied by BAC-FISH were consistent with the ones from SNP array. Some characteristics from this cohort are consistent with previous reports, but many typical features are lacking in our patients. The cardinal features of 6q11-q14 interstitial deletions in this cohort include: umbilical hernia, hypotonia, short stature, characteristic facial features of upslanting palpebral fissures, low set and/or dysplastic ears, high arched palate, urinary tract anomalies, and skeletal/limb anomalies.

Breakpoint

Palpebral fissure

10.1002/ajmg.a.32675

Cite

Citations (8)

Comparative Genomic Hybridization

Archives of Pathology & Laboratory Medicine (2001)

Irene Barrett Brenda Lomax Tatiana Loukianova Steven S. Tang Valia S. Lestou

Abstract Objective.—To demonstrate the effectiveness of comparative genomic hybridization (CGH) for analysis of reproductive pathology specimens in clinical cytogenetics laboratories. Design.—A total of 856 CGH analyses were performed on various placental and fetal tissues derived from 368 specimens of spontaneous abortions and on placentas from 219 pregnancies with live-born infants. The live-born infants were clinically evaluated as normally developed, with either a normal birth weight or with intrauterine growth restriction; some live-born infants had an abnormal prenatal triple screen with normal cytogenetic results on amniotic fluid cell cultures. Results.—Comparative genomic hybridization analysis was successfully performed on 856 samples from spontaneously aborted specimens and term placentas. Failure of analysis occurred in 1.6% of samples and was due to an insufficient amount of tissue for DNA extraction. Comparative genomic hybridization identified aneuploidy in 53% of spontaneous abortion samples and 3.1% of term placentas. Conclusions.—Comparative genomic hybridization analysis is a useful clinical tool for detection of aneuploidy in placental and fetal tissues. It provides a genome-wide screen while eliminating tissue culture failures, culture artifacts, and maternal cell contamination. We present practical guidelines for interpreting CGH profiles derived from human reproductive specimens.

Comparative genomic hybridization

10.5858/2001-125-0081-cgh

Cite

Citations (33)

The utilization of interphase cytogenetic analysis for the detection of mosaicism

Human Genetics (1994)

Brenda Lomax Dagmar K. Kalousek Brian D. Kuchinka Irene Barrett Karen J. Harrison

Interphase

Trisomy

Monosomy

10.1007/bf00212016

Cite

Citations (51)

BPES with atypical premature ovarian insufficiency, and evidence of mitotic recombination, in a woman with trisomy X and a translocation t(3;11)(q22.3;q14.1)

American Journal of Medical Genetics Part A (2012)

Kamilla Schlade‐Bartusiak Lindsay Brown Brenda Lomax Hélène Bruyère Tanya L. Gillan

Abstract Blepharophimosis–ptosis–epicanthus inversus syndrome (BPES) is a rare autosomal dominant disorder characterized by a complex dysgenesis of the eyelids and premature ovarian insufficiency. FOXL2 located at 3q22.3, encoding a forkhead transcription factor, is the only gene known to be responsible for BPES. We describe a patient diagnosed with BPES with atypical ovarian failure, characterized by normal levels of gonadotropins, who was found to have trisomy X as well as a translocation (3;11)(q22.3;q14.1). The translocation breakpoint at 3q22.3 is located upstream of the FOXL2 gene and most likely causes BPES by separating the FOXL2 transcription unit from its cis ‐regulatory sequences. By array analysis we detected mosaicism for the balanced and an unbalanced form of the translocation in blood cells. We propose mitotic recombination as the likely mechanism of the mosaicism formation. Mitotic recombination is a common phenomenon in human cells. Thus, we hypothesize that it may be one of the mechanisms responsible for cryptic imbalances and possible abnormal phenotypes in some carriers of balanced rearrangements. © 2012 Wiley Periodicals, Inc.

Blepharophimosis

Premature ovarian failure

Trisomy

Breakpoint

10.1002/ajmg.a.35516

Cite

Citations (8)

Screening of human placentas for chromosomal mosaicism using comparative genomic hybridization

Birth Defects Research (1999)

Valia S. Lestou Brenda Lomax Irene Barrett Dagmar K. Kalousek

Detection of confined placental mosaicism (CPM) in term placental tissues is usually accomplished by conventional cytogenetic analysis of cultured chorionic stroma and direct preparations from trophoblast or, more recently, by fluorescence in situ hybridization (FISH) on interphase nuclei. In this study, we describe the use of comparative genomic hybridization (CGH) for detection of chromosomal aneuploidy in term placentas and evaluate the sensitivity of this novel approach for CPM diagnosis in multiple placental samples acquired from five pregnancies prenatally diagnosed with CPM7 and CPM16. Each sample of placental villi was separated enzymatically into trophoblast and chorionic stroma, and the level of aneuploidy (three signals/nuclei) in each tissue was determined by FISH analysis, using centromeric DNA probes specific for chromosome 7 (D7Z1/Z2) or 16 (D16Z2). Aneuploidy levels ranged from 5.2–96.1% in the 11 tissues with CPM7 and 9.8–93% in the 29 tissues with CPM16. Subsequently, CGH analysis of DNA from the trophoblast and chorionic stroma of the same tissue sites detected the trisomic clone in all placental tissues with aneuploidy (16%, as determined by FISH analysis). Our results demonstrate the sensitivity of CGH analysis for detection of chromosomal aneuploidy mosaicism and support our contention that the CGH technique is the most effective cytogenetic method for screening term placentas for the presence of CPM. Teratology 59:325–330, 1999. © 1999 Wiley-Liss, Inc.

Comparative genomic hybridization

Chorionic villi

Trisomy

Trophoblast

10.1002/(sici)1096-9926(199905)59:5<325::aid-tera3>3.0.co;2-n

Cite

Citations (45)

Clinical care and other categories posters: structure-systems of care and healthcare delivery

Diabetic Medicine (2016)

A Ramaesh Sarah H. Wild T. Robbins Syed Wasif Gillani B. M. Singh

NI Lone 1,2

Health care delivery

10.1111/dme.51_13048

Cite

Citations (0)

Craniosynostosis associated with distal 5q‐trisomy: Further evidence that extra copy of MSX2 gene leads to craniosynostosis

American Journal of Medical Genetics Part A (2007)

Jia‐Chi Wang Michelle Steinraths Linda Dang Brenda Lomax Patrice Eydoux

Distal 5q-trisomy has been reported in less than 30 patients, with craniosynostosis present in five. We report two new patients with distal 5q-trisomy craniosynostosis. Patient 1 had mild Kleeblattschädel with synostosis of multiple sutures together with wide and medially deviated thumbs and halluces, indicative of Pfeiffer syndrome. Cytogenetic and CGH analyses showed a karyotype of 46,XY,der(10)t(5;10)(q33;q26.3). Patient 2 had a prominent forehead and ridging of the metopic suture. Craniosynostosis of the metopic suture was shown by CT scan. Cytogenetic and CGH analyses disclosed a karyotype of 46,XX,der(17)t(5;17)(q35.1;p13.3). Of the 22 previously reported patients, all had microcephaly and 14 had an abnormal skull shape. Our results support the previous finding that distal 5q-trisomy together with an extra copy of the MSX2 gene leads to abnormal closure of sutures and craniosynostosis.

Trisomy

Craniosynostoses

Microcephaly

10.1002/ajmg.a.31946

Cite

Citations (22)

Inverted duplication with terminal deletion of 5p and no cat‐like cry

American Journal of Medical Genetics Part A (2008)

Jia‐Chi Wang Bradley P. Coe Brenda Lomax Patrick MacLeod Malcolm Parslow

Abstract We report on a 6‐year‐old boy referred for cytogenetics study. A few non‐specific features were observed in the newborn: hypotonia, failure to thrive, seizures, pre‐auricular skin tags. Cat‐like cry was not identified. No remarkable facial dysmorphism, gastrointestinal, respiratory or cardiac abnormalities were identified. At age 4 years, speech and motor skill delays were apparent. Karyotyping and FISH analysis revealed a de novo rearranged chromosome 5p, with subtelomeric deletion of 5p and a duplication of the cri‐du‐chat critical region. Array CGH using sub‐megabase resolution tiling‐set (SMRT) array followed by FISH analysis with labeled BACs showed a deletion of 5pter to 5p15.31 (0–6.9 Mb) and an inverted duplication of the greater part of 5p15.31 to the distal end of 5p14.3 (6.9–19.9 Mb). Although very rare, inverted duplications with terminal deletion (inv dup del) have been reported at different chromosomal ends. Our finding adds a second patient of inv dup del 5p to this growing list, and the potential causative mechanisms for this rearrangement are discussed. Review of the mapping information of cri‐du‐chat patients and the comparison with a previously reported patient suggested that the critical region for cat‐like cry is located within a 0.6 Mb region. © 2008 Wiley‐Liss, Inc.

dup

Subtelomere

Breakpoint

10.1002/ajmg.a.32246

Cite

Citations (18)

Detection of confined placental mosaicism in trisomy 18 conceptions using interphase cytogenetic analysis

Human Genetics (1993)

Karen J. Harrison Irene Barrett Brenda Lomax Brian D. Kuchinka Dagmar K. Kalousek

Trisomy

Chorionic villus sampling

Cytotrophoblast