Clinical trial NCT03955588: Replacement of Cytogenetics by aCGH in Prenatal Diagnosis
Official title: Demonstration Trial on Replacement of Cytogenetics by Array Comparative Genomic Hybridisation (aCGH) in Prenatal Diagnosis
Study type: OBSERVATIONAL
Overall status: COMPLETED
Conditions: Prenatal Diagnosis
Keywords: Cytogenetics
aCGH
Prenatal Diagnosis
Lead sponsor: The University of Hong Kong
Sponsor class: OTHER
First posted: 2019-05-20
Enrollment: 51
Sex: FEMALE
Standard ages: CHILD
ADULT
OLDER_ADULT
Accepts healthy volunteers: no
Observational model: COHORT
Time perspective: PROSPECTIVE
Sampling method: NON_PROBABILITY_SAMPLE
Study population: All women who require invasive prenatal diagnosis will be recruited.

Brief summary: Conventional cytogenetics has been the gold standard for chromosomal analysis in prenatal diagnosis. It allows a microscopic examination for any structural abnormalities of chromosome with a turn-around time of 2 to 3 weeks and it is also labour intensive. Array comparative genome hybridisation (aCGH) provides a platform for a higher resolution analysis of chromosomal aberrations in a shorter period of time. The effectiveness of its application in prenatal diagnosis has been examined. The main clinical limitation lies on the difficult interpretation of certain copy number variants (CNV). Our previous study has demonstrated an increase diagnostic yield of 3.2% using aCGH over conventional cytogenetics in the first-tier test study and by 6% as a further test in a cohort of fetuses with ultrasound abnormality and normal karyotype findings. This finding were consistent with the overall reported of 5.2% to 10% increased detection rate by other studies. Various authorities have also approved the use of aCGH as an adjunct diagnostic tool in prenatal cases with fetal ultrasound abnormalities.

The presence study aims to demonstrate the clinical acceptability on the use of aCGH to replace cytogenetics in prenatal diagnosis. For patients requiring invasive prenatal diagnosis by chorionic villus sampling or amniocentesis, they will be offered the options of having either conventional cytogenetics or aCGH. A standard unbiased counselling procedure will be performed by well trained midwives. For patients opting for conventional cytogenetics, the current procedure of karyotyping will be performed. For those opting for aCGH, a quantitative fluorescent Polymerase Chain Reaction (PCR) will be performed first to exclude common aneuploidies and triploidies. aCGH will be arranged for those with normal PCR results and conventional cytogenetics will be reserved for visualization of clinically significant CNVs.

All patients will be asked to complete the same questionnaire that has been adopted for the study on "Questionnaire survey on Knowledge and Acceptance on Application of whole genome array Comparative Genomic Hybridisation (aCGH) in Prenatal Diagnosis".

Detailed description: Conventional cytogenetics has been the gold standard for chromosomal analysis in prenatal diagnosis. It allows a microscopic examination for any structural abnormalities of chromosome with a turn-around time of 2 to 3 weeks and it is also labour intensive. Array comparative genome hybridisation (aCGH) provides a platform for a higher resolution analysis of chromosomal aberrations in a shorter period of time. The effectiveness of its application in prenatal diagnosis has been examined (Callaway, Shaffer, Chitty, Rosenfeld, \& Crolla, 2013). The main clinical limitation lies on the difficult interpretation of certain copy number variants (CNV). Our previous study has demonstrated an increase diagnostic yield of 3.2% using aCGH over conventional cytogenetics in the first-tier test study and by 6% as a further test in a cohort of fetuses with ultrasound abnormality and normal karyotype findings (Kan et al., 2014). This finding were consistent with the overall reported of 5.2% to 10% increased detection rate by other studies (de Wit et al., 2014; Hillman et al., 2013; Hillman et al., 2011). Various authorities have also approved the use of aCGH as an adjunct diagnostic tool in prenatal cases with fetal ultrasound abnormalities (American College of Obstetricians \& Gynecologists, 2013; Novelli et al., 2012).

Eligibility criteria: Inclusion Criteria:

All pregnant women requiring chorionic villus sampling or amniocentesis at Tsan Yuk Hospital

Exclusion Criteria:

Patients who cannot read or understand Chinese or English

Primary outcomes:
measure: The preference of aCGH to conventional cytogenetics
timeFrame: At the time of recruitment
Secondary outcomes:
measure: Cost-effectiveness analysis of chromosomal microarray as primary test for prenatal diagnosis in Hong Kong
timeFrame: After completion of the aCGH for the last recruited subject in 2016
Other outcomes:
Locations:
Study officials:
References:
citation: American College of Obstetricians and Gynecologists Committee on Genetics. Committee Opinion No. 581: the use of chromosomal microarray analysis in prenatal diagnosis. Obstet Gynecol. 2013 Dec;122(6):1374-7. doi: 10.1097/01.AOG.0000438962.16108.d1.
citation: Callaway JL, Shaffer LG, Chitty LS, Rosenfeld JA, Crolla JA. The clinical utility of microarray technologies applied to prenatal cytogenetics in the presence of a normal conventional karyotype: a review of the literature. Prenat Diagn. 2013 Dec;33(12):1119-23. doi: 10.1002/pd.4209. Epub 2013 Sep 8.
citation: de Wit MC, Srebniak MI, Govaerts LC, Van Opstal D, Galjaard RJ, Go AT. Additional value of prenatal genomic array testing in fetuses with isolated structural ultrasound abnormalities and a normal karyotype: a systematic review of the literature. Ultrasound Obstet Gynecol. 2014 Feb;43(2):139-46. doi: 10.1002/uog.12575.
citation: Hillman SC, McMullan DJ, Hall G, Togneri FS, James N, Maher EJ, Meller CH, Williams D, Wapner RJ, Maher ER, Kilby MD. Use of prenatal chromosomal microarray: prospective cohort study and systematic review and meta-analysis. Ultrasound Obstet Gynecol. 2013 Jun;41(6):610-20. doi: 10.1002/uog.12464. Epub 2013 May 7.
citation: Hillman SC, Pretlove S, Coomarasamy A, McMullan DJ, Davison EV, Maher ER, Kilby MD. Additional information from array comparative genomic hybridization technology over conventional karyotyping in prenatal diagnosis: a systematic review and meta-analysis. Ultrasound Obstet Gynecol. 2011 Jan;37(1):6-14. doi: 10.1002/uog.7754.
citation: Kan AS, Lau ET, Tang WF, Chan SS, Ding SC, Chan KY, Lee CP, Hui PW, Chung BH, Leung KY, Ma T, Leung WC, Tang MH. Whole-genome array CGH evaluation for replacing prenatal karyotyping in Hong Kong. PLoS One. 2014 Feb 5;9(2):e87988. doi: 10.1371/journal.pone.0087988. eCollection 2014.
citation: Novelli A, Grati FR, Ballarati L, Bernardini L, Bizzoco D, Camurri L, Casalone R, Cardarelli L, Cavalli P, Ciccone R, Clementi M, Dalpra L, Gentile M, Gelli G, Grammatico P, Malacarne M, Nardone AM, Pecile V, Simoni G, Zuffardi O, Giardino D. Microarray application in prenatal diagnosis: a position statement from the cytogenetics working group of the Italian Society of Human Genetics (SIGU), November 2011. Ultrasound Obstet Gynecol. 2012 Apr;39(4):384-8. doi: 10.1002/uog.11092.