Post-mortem rapid aneuploidy testing for holoprosencephaly.

BACKGROUND: Abortion and fetal death are common in fetuses with holoprosencephaly, so genetic examinations often have to be made in a post-mortem setting. The efficiency of the conventional karyotyping using cultured fibroblasts in these situations is limited due to frequent culture failure. In the current study, archived cases of holoprosencephaly, where post-mortem genetic evaluation was requested and sufficient frozen material was available, were reevaluated using the quantitative fluorescence polymerase chain reaction (QF-PCR) technique. METHODS: Testing for aneuploidies of chromosomes 13, 15, 16, 18, 21, 22, X, and Y with the QF-PCR technique was carried out on DNA isolated from archived frozen chorionic villi in seven cases of holoprosencephaly. RESULTS: QF-PCR was successful in all seven cases. Two cases of trisomy 13, two cases of triploidy, and one case of trisomy 18 was found meaning a 71% diagnostic yield. The success rate of QF-PCR (100%, 7/7) was superior compared to conventional karyotyping (43%, 3/7). CONCLUSIONS: Rapid aneuploidy testing using the QF-PCR technique is a simple, reliable, time- and cost-effective method sufficient to conclude the etiologic investigation in the majority of holoprosencephaly cases post-mortem.

Fetal anatomy scan with integrated nuchal translucency and combination of PAPP-A and fßhCG for prediction of aneuploidy.

BACKGROUND: Nuchal translucency (NT) is an important finding of early fetal anatomy scan because of the association with genetic and structural anomalies. Enlarged nuchal translucency can be easily detected even without measurement on fetal anatomy scan as a neck pathology. Because of demanding criteria for measurning NT in established prenatal aneuploidy screening we came with an idea of improvement and simplification with availabe methods. The aim of this study is to compare established screening methods with new model of screening composed of fetal anatomy scan with integrated nuchal translucency and combination of PAPP-A and fßhCG. METHODS: A prospective one center study analyzed a total of 351 pregnancies between January 2017 and December 2020. Sonographic measurement of NT and fetal anatomy scan (FAS) were performend with biochemical testing from blood sample in the first trimester. Combined screening and fetal anatomy scan was performed. Patients with a pathological screening or with structural defects underwent an invasive procedure. In patient with positive screenining who missed the first trimester invasive procedure, amniocentesis was performed. Fetuses were divided into two groups according to positive or negative karyotype and to calculate sensitivity and specificity of screening methods. From statistical methods regression analysis, significance p of individual predictor, sensitivity and specificity with graphic drawing of ROC charts were used. Data were analyzed using statistical tools of Microsoft Excel 365 and BESH stat. RESULTS: Four models for aneuploidy screening were tested. 1) Model of "Age at the time of diagnosis" was slightly significant predictor with insignificant odds ratio (P=0.04, OR=1). 2) Model of" First trimester biochemical screening" (age, free beta human chorionic gonadotropine - fßhCG and pregnancy associated plasmatic protein A - PAPP-A) were significant (P=0.0001; LR=21) with sensitivity of 87.5 % and specificity of 65.7 %. 3) Model of "First trimester combined test" (age of patients at the time of diagnosis, fßhCG, PAPP-A, NT) was significant (P=7.9 x10-14, LR=67, sensitivity 87 %, specificity 80 %). 4) Model of "Fetal anatomy scan with biochemistry" (structural abnormality finding with combination including age, fßhCG and PAPP-A) was significant (P=4.9x10-18, LR=87, sensitivity 95 %, specificity 80 %). CONCLUSION: Fetal anatomy scan combined with age, fßhCG and PAPP-A has the highest sensitivity and specificity for both, the detection of fetal aneuploidies and structural abnormalities. Our study shows that fetal anatomy scan is the best possible option for first trimester diagnostics (Tab. 4, Fig. 5, Ref. 16).